# GCN_circulars

GRB_name: GRB090423A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9242
SUBJECT: GRB 090423: Y-band field calibration update/correction
DATE:    09/04/25 02:31:03 GMT
FROM:    Myungshin Im at Seoul Nat U  <mim@astro.snu.ac.kr>

  M. Im, Y. Jeon, C. Choi, W. Park, I. Lee Seoul National Univ),
  Y.-B. Jeon (KASI) and Y. Urata (NCU) on behalf of EAFON team.

  The Y-band calibration data reported earlier by Im et al.
  (GCN 9221) have been updated with a revised zero point,
  and the catalog now includes more objects.

  The updated field calibration data are available
  at the same location as before:

  http://astro.snu.ac.kr/~mim/grb/readme
  http://astro.snu.ac.kr/~mim/grb/grb090423_ycal.dat
  http://astro.snu.ac.kr/~mim/grb/yobj.reg
  http://astro.snu.ac.kr/~mim/grb/chart.gif

  We thank the LOAO operator, J. Yoon for his assistance for this
  observation.


GRB_name: GRB090424A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9243
SUBJECT: GRB 090424 Gemini-South Redshift
DATE:    09/04/25 03:02:24 GMT
FROM:    Ryan Chornock at UC Berkeley  <chornock@astro.berkeley.edu>

R. Chornock, D. A. Perley, S. B. Cenko, and J. S. Bloom (UC Berkeley) report on
behalf of a larger collaboration:

We obtained optical spectra of the afterglow of GRB 090424 (Cannizzo et al., GCN
9223) using GMOS on Gemini-South.  Our spectra cover the wavelength range of
4400-8600 angstroms.  Our first 1200s exposure, starting at 01:51:56 April 25 UT
(11.7 hr after the trigger) reveals.a pair of absorption lines at 6077 and 6130
Angs, which we identify as the Ca II H+K doublet at z=0.544.  Additionally, an
emission line is present at 5758 A, which is consistent with the [O II] 3727
doublet at the same redshift, which we therefore identify as the redshift of the
host galaxy.  We note that this redshift is significantly higher than the
photo-z noted by Evans & Holland (GCN 9226).


GRB_name: GRB090423A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9244
SUBJECT: GRB090423: Y-band limit
DATE:    09/04/25 04:12:16 GMT
FROM:    Myungshin Im at Seoul Nat U  <mim@astro.snu.ac.kr>

  M. Im, C. Choi, Y. Jeon, W. Park, I. Lee (Seoul National Univ),
  Y.-B. Jeon (KASI) and Y. Urata (NCU) on behalf of EAFON team.

   We took a series of Y-band images of GRB090423 using the 1.0m
  telescope at Mt. Lemmon (Arizona, US) operated by the Korea Astronomy
  Space Science Institute.

   We do not detect the afterglow in a stacked image with the
  total exposure time of 78 min, placing an upper limit of Y < 19.8 (Vega)
  at 3-sigma at the mid point of UT April 24, 06:16. The photometry
  calibration was done using the calibration data reported
  in Im et al. (GCN 9242, 9221).

  We thank the LOAO operator, J. Yoon for his assistance for this
  observation.


GRB_name: GRB090424A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9245
SUBJECT: GRB 090424: GROND Observations of the Optical/NIR Afterglow
DATE:    09/04/25 04:34:34 GMT
FROM:    Aybuke Kupcu Yoldas at ESO  <ayoldas@eso.org>

F. Olivares (MPE Garching), A. Kupcu Yoldas (ESO), J. Greiner, A. Yoldas 
(both MPE Garching) report on behalf of the GROND team:

We observed the field of GRB 090424 (Swift trigger 350311;Cannizzo et 
al., GCN #9223) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 
2008, PASP 120, 405) mounted at the 2.2 m ESO/MPI telescope at La Silla 
Observatory (Chile).

Observations started at 02:52 UT on 25 April, ~12.5 hours after the GRB 
trigger, and are continuing. They were performed at an average seeing of 
1.0 and at an average airmass of 1.45.

We clearly detect the optical afterglow (Cannizzo et al. GCN #9223; Yuan 
et al. GCN #9224; Xin et al. GCN #9225; Schady et al. #9234; Gorosabel 
et al. GCN #9236).

Preliminary photometry yields the following AB magnitudes in stacked 
images of the first OB,  obtained using SDSS/2MASS stars as reference:

Filter  Exp[s]  AB Mag  MagErr
----------------------------------------
g'      4x115 20.98 0.02
r'      4x115 20.42 0.04
i'      4x115 20.01 0.04
z'      4x115 19.64 0.02
J  48x10 19.08 0.09
H  48x10 18.62 0.03
K  48x10 18.29 0.04

Given magnitudes are not corrected for the expected Galactic foreground 
extinction corresponding of E_(B-V)=0.03 mag (Schlegel et al. 1998).
These magnitudes combined with the results of previous observations 
(Schady et al. GCN #9234, Guidorzi et al. GCN #9238) indicate a 
flattening in the afterglow light-curve.


GRB_name: GRB090424A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9246
SUBJECT: GRB 090424: THO optical observations
DATE:    09/04/25 05:35:50 GMT
FROM:    Veli-Pekka Hentunen at Taurus Hill Obs,A95  <veli-pekka.hentunen@kassiopeia.net>

Markku Nissinen (Taurus Hill Observatory) and Veli-Pekka Hentunen (Taurus
Hill Observatory) report:


We used 0.35m C14 XLT telescope with SBIG ST-8XME CCD at Taurus Hill Observatory
(Varkaus, Finland) for follow-up observations of GRB090424. The observations 
were started on April 24, at 19:59 UTC (5.8 hours after the burst) and stopped
on April 24, at 23:11 UTC. Sixteen unfiltered 600 seconds images were taken. 
We detected clear optical afterglow object at the position of RA 12h 38m 05s.12 and DEC 
+16o 50' 15".2 with respect to POSSII F/USNO-B1.0 which is in good correlation 
with enhanced Swift XRT-UVOT position. Upper limit for the observations is >20.4 mag.
Quoted upper limit has been derived using POSSII F and USNO-B1.0 field stars 
as reference.

Filter     Tmid(s)      Exp(s)     Mag (CR) USNO-B1.0
                
u         20:14:23      600      19.55+/-0.37
u         20:37:30      600      19.95+/-0.38
u         21:32:48      600      20.15+/-0.34

A jpeg preview of the observation showing the position of the afterglow is 
available at this URL: http://cutenews.kassiopeia.net/data/upimages/grb090424_ticks.jpg


GRB_name: GRB090424A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9247
SUBJECT: GRB 090424 : Lulin 1m telescope optical observations
DATE:    09/04/25 06:06:14 GMT
FROM:    Yuji Urata at Nat. Central U.  <urata@astro.ncu.edu.tw>

Y. Urata(NCU), K. Y. Huang (ASIAA) 
on behalf of EAFON report;

"We have observed optical afterglow of GRB090424 (Cannizzo et al., GCN
#9223, Yuan et al. GCN #9224; Xin et al. GCN #9225; Schady et
al. #9234; Gorosabel et al. GCN #9236; Urata et al. GCN #9240,
Olivares et al GCN #9245; Nissinen et al. GCN #9246) using Lulin 1m
telescope (LOT) with B, V, R, I and z'-band filters.  Observations
started at 14:34:18 UT on 24 April.  These LOT images show the
afterglow clearly. Based on our preliminary photometry compared with
USNO B1.0 stars, the R-band light curve between 1329 sec and 13303 sec
after the burst is well fitted by a simple power law with the decay
index 0.71."


GRB_name: GRB090424A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9248
SUBJECT: GRB090424: BVRI/R-band detection after 15 hrs burst
DATE:    09/04/25 06:52:02 GMT
FROM:    Myungshin Im at Seoul Nat U  <mim@astro.snu.ac.kr>

  M. Im, W. Park, Y. Jeon, I. Lee (CEOU/Seoul National Univ),
  Y.-B. Jeon (KASI) and Y. Urata (NCU) on behalf of EAFON team.

   We took BVRI-band images of GRB090424 (GCN 9223)
  using the 1.0m telescope at Mt. Lemmon (Arizona, US)
  operated by the Korea Astronomy Space Science Institute.
   The whole sequence of the observation started at
  2009 April 25, 04:30:19 UT, among which R-band observation
  started at 04:58:32.22.

   From a stacked image of 6 frames (3 min exp. each),
  we cleary detect the afterglow at R=19.9 +- 0.14 mag, calibrated
  against USNO-B1 stars in the vicinity. The mid-point of the
  obseravation is April 25, 05:10:57 UT (14.97 hrs after
  the burst).
   Analysis of the BVI data is ongoing.

   We thank the LOAO operator, J. Yoon for his assistance for this
  observation.


GRB_name: GRB090423A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9249
SUBJECT: VLA radio observation of high-z GRB 090423
DATE:    09/04/25 10:41:23 GMT
FROM:    Poonam Chandra at U Virginia/NRAO  <pc8s@virginia.edu>

"Poonam Chandra (RMC), Dale A. Frail (NRAO) and S. R. Kulkarni (Caltech)
report on behalf of a larger collaboration:

"We used the Very Large Array to observe the field of view toward the
high redshift GRB 090423 (GCN 9198) at a frequency of 8.46 GHz on 2009
Apr. 25.00 UT. We do not detect any radio emission either within the
Swift-XRT error circle (GCN 9205) or at the UKIRT K-band position (GCN
9202). The 3-sigma upper limit on the radio flux density of GRB
afterglow is 135 uJy (map rms 45 uJy).

The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."


GRB_name: GRB090424A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9250
SUBJECT: GRB 090424: WHT ISIS spectroscopy 
DATE:    09/04/25 17:23:03 GMT
FROM:    Klaas Wiersema at U of Leicester  <kw113@star.le.ac.uk>

K. Wiersema (Leicester), A. de Ugarte Postigo (ESO) and A. Levan (Warwick) 
report on behalf of a larger collaboration:

We observed the afterglow of GRB 090424 (Cannizzo et al, GCN 9223) with 
the ISIS spectrograph on the William Herschel Telescope at the 
Observatorio del Roque de los Muchachos on La Palma, ~8 hours after burst.

In the spectrum we find several lines, among others the Mg II doublet 
(with restframe EW > 1 A of the 2796 line), Fe II, Na I. Through these we 
confirm the redshift of z=0.544 found by Chornock et al (GCN 9243). 
Continuum is detected up to at least 3200 A, giving an upper limit to the 
GRB redshift of 1.6, consistent with the emission and absorption redshift 
of 0.544.

We thank the staff of the WHT, in particular O. Vadivescu, for support for 
these observations.


GRB_name: GRB090423A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9251
SUBJECT: GRB 090423: Fermi GBM observation (correction of isotropic equivalent energy)
DATE:    09/04/25 20:05:22 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: 

"The isotropic equivalent energy of GRB 090423 given in 
GCN Circular 9229 has been erroneously computed. 

At a redshift of about 8 the correct value for the isotropic 
equivalent energy is E_iso = (1.0 +/- 0.3)E+53 ergs. 

This value was determined from the observed event fluence of 
(1.1 +/- 0.3)E-06 erg/cm^2 in the 8 to 1000 keV energy range 
(observer's frame!).

We apologize for this mistake."


GRB_name: GRB090424A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9252
SUBJECT: GRB 090424: MASTER-Net prompt optical limit
DATE:    09/04/25 20:29:42 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc@observ.inetcomm.ru>

E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina,
D.Kuvshinov, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov
Sternberg Astronomical Institute, Moscow State University

K.Ivanov, S.Yazev
Irkutsk State University

A. Tlatov, A.V. Parhomenko,
Kislovodsk Solar Station of the Pulkovo Observatory

V.Krushinski, I.Zalognikh, T.Kopytova
Ural State University, Kourovka


There are 6 MASTER Very Wide Field cameras located at Kislovodsk and Irkutsk 
with common FOW = 6000 square degrees (http://observ.pereplet.ru/).

One of the two  MASTER Very Wide Field Cameras located at Irkutsk
(D=50 mm, 2x1000 square degrees, 11 Mpx, 72" per pix in binning regime) has 
observed  UVOT error box (Cannizzo et al., GCN 9223) with 1s exposure befoure, 
during and after GRB Time without time gap between images.
The error box is near at the center of our FOW.

Our unfiltered images are calibrated relative to Tycho stars (V) and very 
close to V band.
The magnitude limit of the each emage is  ~8 m at the center of FOW (some 
cloudy on the sky). The limit of coadded six images ~ 9 m.

We do not detect OT.

Our observations results:

----------------------------------------------------------------------
Fermi GRB Trigg.*     Exposure   Mag Limit   Optical Flux        Coadd?
time (sec)            (sec)        (m)       (erg/sm^2 s)
----------------------------------------------------------------------
     -2                  1          8.1        1.3x10^-8            No
     -1                  1          8.1        1.3x10^-8            No
      0                  1          8.0        1.4x10^-8            No
     +1                  1          8.0        1.4x10^-8            No
     +2                  1          8.0        1.4x10^-8            No
     +3                  1          7.9        1.5x10^-8            No
     +4                  1          8.0        1.4x10^-8            No
     +5                  1          8.0        1.4x10^-8            No
  -60 : +120             1          ~8        ~1.4x10^-8            No
     -6                  6          8.9        7.0x10^-9            Yes
     +0                  6          8.7        7.3x10^-9            Yes
     +6                  6          8.8        7.2x10^-9            Yes
    +12                  6          8.9        7.0x10^-9            Yes
    -60                 60          9.7        3.0x10^-9            Yes
      0                 60          9.7        3.0x10^-9            Yes
     60                 60          9.5        3.5x10^-9            Yes
-----------------------------------------------------------------------
*Fermi GBM Trigger Time = 14:12:08.67 (Connaughton, GCN 9230)  1% 
coincident with our start zero image time.

1). the optical fluence during  GRBurst is limited by

  0 up to +6 s                       ~<=  1 x 10E-7 erg/cm^2
  0 up to +60 s                       <=  5 x 10E-7 erg/cm^2

including  total absorbtion 1 magnitude in V band.
(The absorption column density NH = (0.20 +/-  0.01) x10^22 cm^-2
from Swift XRT spectrum data, Margutti, GCN 9237).

The event fluence (8-1000 keV) in this time interval is
(5.2 +/- 0.1)E-05 erg/cm^2 (Connaughton, GCN 9230).

So:

2).

Optical-Fluence(6s)/Gamma-Fluence (8-1000 keV)  ~ < 1/500
Optical-Fluence(60s)/Gamma-Fluence(8-1000 keV)  ~ < 1/100

The same ratio for  GRB080319B is

Optical-Fluence/Gamma-Fluence(8 - 1000 keV) ~ 1/140

(Naked Eye GRB, Racusin, Karpov et al., Nature, vol.455, 183, 2008).


The light curve and film  of our observations  is available at

http://observ.pereplet.ru/images/GRB090424/GRB090424.html


The reduction is continued.

The message may be cited.

mailto: lipunov@sai.msu.ru


GRB_name: GRB090424A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9253
SUBJECT: GRB090424: R-band detection (37.5 hrs post-burst), jet break?
DATE:    09/04/26 11:30:29 GMT
FROM:    Myungshin Im at Seoul Nat U  <mim@astro.snu.ac.kr>

  M. Im, W. Park, Y. Jeon, I. Lee (CEOU/Seoul National Univ),
  Y.-B. Jeon (KASI) and Y. Urata (NCU) on behalf of EAFON team.

   We continued the follow-up observation of GRB090424 (Cannizzo et al.
  GCN 9223) in BVR using the 1.0m telescope at Mt. Lemmon (Arizona, US)
  operated by the Korea Astronomy Space Science Institute.
   The R-band imaging started at 2009 April 26, 03:11:23 UT.
   The mid-point of the R-band obseravation is April 26,
  03:39:43 UT (37.45 hrs after the burst).

   From a stacked image of 13 frames (3 min exp. each),
  the afterglow is visible at R=20.96 +- 0.17 mag, suggesting
  a significant fading occurred since last night (Im et al. GCN 9248),
  more than the expected amount of fading with the power-law index
  of 0.71 reported earlier (Urata et al. GCN 9247). This suggests that
  jet break might have occured. The afterglow is also visible in
  B- and V-bands.
   The photometry was calibrated against USNO-B1 stars in the vicinity.

   We thank the LOAO operator, J. Yoon for his assistance for this
  observation.


GRB_name: GRB090426A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9254
SUBJECT: GRB 090426: Swift detection of a burst with an optical counterpart
DATE:    09/04/26 13:02:36 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

J. R. Cummings (NASA/UMBC), D. N. Burrows (PSU),
N. Gehrels (NASA/GSFC), C. Gronwall (PSU), C. Guidorzi (U Ferrara),
S. T. Holland (CRESST/USRA/GSFC), H. A. Krimm (CRESST/GSFC/USRA),
J. Mao (INAF-OAB), R. Margutti (Univ Bicocca&OAB),
F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester),
D. M. Palmer (LANL), B. A. Rowlinson (U Leicester),
M. H. Siegel (PSU) and T. N. Ukwatta (GSFC/GWU) report on behalf of
the Swift Team:

At 12:48:47 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090426 (trigger=350479).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 189.091, +32.966 which is 
   RA(J2000) = 12h 36m 22s
   Dec(J2000) = +32d 57' 56"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed multiple narrow
peaks extending over 25 seconds.  The peak count rate
was ~2500 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 12:50:11.8 UT, 84.6 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 189.07405, 32.98476 which is equivalent
to:
   RA(J2000)  = 12h 36m 17.77s
   Dec(J2000) = +32d 59' 05.1"
with an uncertainty of 3.9 arcseconds (radius, 90% containment). This
location is 84 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of
1.51e+20 cm^-2 (Kalberla et al. 2005). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 89 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 12:36:18.07 = 189.07531
  DEC(J2000) = +32:59:09.6  = 32.98600
with a 90%-confidence error radius of about 0.75 arc sec. This position is 86.2
arc sec. from the center of the BAT error circle. The estimated magnitude is
17.50 with a 1-sigma error of about 0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.02. 

Burst Advocate for this burst is J. R. Cummings (jayc AT milkyway.gsfc.nasa.gov). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090426A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9255
SUBJECT: GRB 090426: TNT confimation of optical counterpart
DATE:    09/04/26 13:32:17 GMT
FROM:    W.K. Zheng at NAOC  <zwk@bao.ac.cn>

L.P. Xin, W.K. Zheng, Y.L. Qiu, J.Y. Wei,
j. Wang, J.S. Deng, Y. Urata and J.Y. Hu 
on behalf of EAFON report:

TNT quickly responsed to the GRB 090426 (Swift trigger 350479;
Cummings et al. GCN 9254) in automatical mode, the first
images was taken start 12:50:03 (UT), 76s after the burst.
We detect a fading source at the position consistent with the
UVOT coordinate (Cummings et al. GCN 9254) thus confirmed the
OT of burst GRB 090426. The brightness in white band
is ~16.4 at 76s after the burst calibrated with USNO A-2.0 R band.
Observation is still under going.
Spectral observation is encouraged.

This message may be cited.

[GCN OPS NOTE(26apr09): Per author's request, the word "short" was removed
removed from the second sentence.]


GRB_name: GRB090426A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9256
SUBJECT: GRB 090426: inspection of SDSS images
DATE:    09/04/26 15:42:35 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>

P. D'Avanzo (INAF-OAB/Univ. Bicocca), E. Palazzi (IASF-Bo), C. C. Thoene 
(INAF-OAB), E. Maiorano (IASF-Bo), G. Chincarini (Univ. Bicocca). L.A. 
Antonelli, S. Piranomonte (INAF-OAR) report, on behalf of the CIBO 
collaboration:

Inspection of archival Sloan Digital Sky Survey images reveals no object 
near the position of the optical afterglow (Cummings et al GCN 9254, Xin 
et GCN 9255) of GRB 090426 down to the SDSS magnitude limits. The 
nearest object is a faint (and apparently extended) source located at 
the following position (J2000) :

RA = 12:36:19.49
DEC = +32:59:05.5

which is about 18" away from the optical afterglow position provided by 
Cummings et al (GCN 9254). According to the SDSS this object have r = 
19.71  0.04 and a photo-z of 0.3. At this redshift the angular 
separation corresponds to about 80 kpc. Given the large offsets, this 
object is unlikely to be related with GRB 090426.


GRB_name: GRB090426A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9257
SUBJECT: GRB 090426, RIMOTS optical upper limits
DATE:    09/04/26 15:53:43 GMT
FROM:    Kenta Kono at Miyazaki U  <kenta0514@astro.miyazaki-u.ac.jp>

K.Kono, K.Noda, E.Sonoda, N.Ohmori, H.hayasi, 
A.Daikyuji, Y.Nisioka, M.Yamauchi
(University of Miyazaki)

 We have observed the field covering the error circle of
GRB090426 (Swift trigger 350479, GCN 9254, J. R. Cummings et al.) 
with the unfiltered CCD camera on the 30-cm telescope 
at University of Miyazaki.
The observation was started 12:50:29 UT (1.7 min. after the Swift trigger), 
under cloudy condition.
First analyzable image was obtained at 12:57:06 UT (6.5 min. after the Swift trigger). 

We have compared our data of 30 sec exposures
with the USNO-A2.0 catalog,
There is no new source at the reported position.
(GCN 9254, J. R. Cummings et al.)

the upper limits are as follows:
--------------------------------------------------------------
Start(UT)   End(UT)    Num. of frames    Limit (mag.)
--------------------------------------------------------------
12:57:06    12:57:36          1            15.3
12:57:06    13:17:26         10            16.8
---------------------------------------------------------------


GRB_name: GRB090426A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9258
SUBJECT: GRB090426: Observation for Optical counterpart from MIRO
DATE:    09/04/26 16:36:42 GMT
FROM:    Kiran S Baliyan at Physical Research Lab, Ahmedabad,India  <baliyan@prl.res.in>

 K.S. Baliyan, Sunil Chandra and  J.K. Jain (MIRO-PRL, Ahmedabad, India)
report:

We observed the field around the position of the optical counterpart of
GRB 090426 (Cummings et al GCN 9254, Xin et GCN 9255) usinmg 1.2m
telescope and 1296x1152 pixels CCD. The observations were made in white
band (4x60s), R band (4x120s) starting at UT 14:41:05 on April 26, 2009.
After a careful comparison with the DSS field, we did not notice any new
source near (couple of arcsecs) the said position of the optical afterglow
of GRB 090426 as reported in GCNs 9254 & 9255, down to the limit of 19.3
in R.
  This message may be cited.


GRB_name: GRB090426A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9259
SUBJECT: GRB 090426: Enhanced Swift-XRT position
DATE:    09/04/26 18:20:57 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 2159 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 090426, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 189.07496, +32.98606 which is equivalent
to:

RA (J2000): 12h 36m 17.99s
Dec (J2000): +32d 59' 09.8"

with an uncertainty of 1.7 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, arXiv:0812.3662).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB090424A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9260
SUBJECT: Detection of bright radio afterglow of GRB 090424 with the VLA
DATE:    09/04/26 18:29:16 GMT
FROM:    Poonam Chandra at U Virginia/NRAO  <pc8s@virginia.edu>

Poonam Chandra (RMC) and Dale A. Frail (NRAO) report on
behalf of a larger collaboration:

"We used the Very Large Array to observe the field of view toward the
GRB 090424 (GCN 9223) at a frequency of 8.46 GHz on 2009 Apr 26.09 UT.
We detected a bright radio afterglow at the UVOT position (GCN 9223).
The GRB radio flux density is 673 +/- 39 uJy.

The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."


GRB_name: GRB090423A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9261
SUBJECT: GRB 090423: GROND second epoch imaging and refined SED
DATE:    09/04/26 18:38:40 GMT
FROM:    Thomas Kruehler at MPE/MPI  <kruehler@mpe.mpg.de>

T. Kruehler, J. Greiner and F. Olivares (all MPE Garching) report on behalf
of the GROND team:

We obtained a second epoch of imaging of the field of GRB 090423 (Swift 
trigger 350184, H. Krimm et al., GCN #9198), which started on 25 Apr. 2009 
at 00:44 UT, 40.8 h after the trigger.

In the second epoch, the NIR afterglow (Tanvir et al. GCN #9202) is 
undetected in stacked images with a total integration time of 4800~s in 
each of J, H and K down to limiting AB magnitudes of J_AB > 22.7, H_AB > 
22.3 and K_AB > 21.6.

Together with the magnitudes reported in Olivares et al. (GCN #9215) this 
implies a fading with a power law index faster than 1.2. This lower limit 
on the temporal decay index is consistent with that found for the X-ray 
afterglow at a similar time interval (G. Stratta & M. Perri, GCN #9212).

In addition we report on a refined analysis of the GROND photo-z from 
Olivares et al. (GCN #9215). Using an improved photometric calibration and 
including the deep z' band upper limit from Perley et al. (GCN #9217) which 
is contemporaneous to our GROND imaging, we find a refined photometric 
redshift of 8.0+0.4-0.8 (90% confidence level). The error range is unlikely 
to improve due to the gap between the z' and J bands (for the negative 
error), and the width of the J filter band (for the positive error).

This range covers the previous claims from photometric (GCNs #9213, #9215, 
#9217) and spectroscopic observations (GCNs #9219, #9222). The SED is well 
described with a power law of index ~1. No signatures of intrinsic dust are 
evident with an upper limit of A_V < 0.5, assuming a SMC dust reddening 
template.


GRB_name: GRB090426A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9262
SUBJECT: GRB 090426: Swift-XRT refined analysis
DATE:    09/04/26 20:27:04 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi (Univ. Ferrara), R. Margutti (Univ. Bicocca & INAF-OAB),
J. Mao (INAF-OAB), and J. R. Cummings (NASA/UMBC) report on behalf of
the Swift-XRT team:

We have analysed the first two orbits of Swift-XRT data obtained for
GRB 090426 (Cummings et al. GCN Circ. 9254), covering 3.0 ks of
Photon Counting (PC) mode data, between 88 s and 13.8 ks after the trigger.
The UVOT-enhanced XRT position was given by Osborne et al. in GCN Circ. 
9259.

The light-curve can be modelled by a simple power-law, with
a decaying index of 0.91 +/- 0.06 (chisq/dof=27.1/25).

The spectrum extracted from PC data in the time interval from 88 s
to 5.6 ks can be modelled with an absorbed power-law, with a photon
index of 1.96 +/- 0.10 and a column density consistent with the Galactic
value of 1.5e20 cm^-2 (Kalberla et al. 2005), with a 90% confidence upper
limit of 3.7e20 cm^-2. The observed (unabsorbed) 0.3 -10 keV flux over
this time interval is 1.1e-11 (1.2e-11) erg cm^-2 count^-1.
Uncertainties are given at 90% confidence.

If the light-curve continues to decay with alpha ~0.91, the count rate 24
hours after the burst is estimated to be 3.9e-3 count s^-1, which
corresponds to an observed flux of 1.7e-13 erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00350479 .

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090426A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9263
SUBJECT: GRB 090426: Swift-BAT refined analysis
DATE:    09/04/26 20:40:16 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

G. Sato (ISAS), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL),
A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090426 (trigger #350479)
(Cummings, et al., GCN Circ. 9254).  The BAT ground-calculated position is
RA, Dec = 189.082, 32.978 deg, which is 
   RA(J2000)  =  12h 36m 19.7s 
   Dec(J2000) = +32d 58' 40.6" 
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 32%.

The mask-weighted light curve shows a few overlapping peaks starting 
at ~T-0.1 sec, peaking at T+0.5 sec, and ending at ~T+1.5 sec.
T90 (15-350 keV) is 1.2 +- 0.3 sec (estimated error including systematics).
 
The time-averaged spectrum from T-0.0 to T+1.3 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.93 +- 0.22.  The fluence in the 15-150 keV band is 1.8 +- 0.3 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.03 sec in the 15-150 keV band
is 2.4 +- 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/350479/BA/


GRB_name: GRB090426A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9264
SUBJECT: GRB 090426 Keck LRIS redshift
DATE:    09/04/26 21:36:18 GMT
FROM:    Ryan Chornock at UC Berkeley  <chornock@astro.berkeley.edu>

E. Levesque (IfA, U. Hawaii), R. Chornock (UC Berkeley), L. Kewley (IfA, U.
Hawaii), J. S. Bloom (UC Berkeley), J. X. Prochaska (UCO/Lick), D. A. Perley, S.
B. Cenko, and M. Modjaz (UC Berkeley) report:

We obtained optical spectra of the afterglow of GRB 090426 (Cummings et al., GCN
9254) using LRIS on the Keck-I telescope, covering the wavelength range of
3000-9940 Angstroms.  Our first exposures started at 13:55 UT, 1.1 hrs after the
BAT trigger.  Preliminary analysis of the spectra reveals a set of absorption
lines at 4387, 5030, 5061, and 5592 Angstroms, which we identify as Lyman-alpha,
Si IV 1394, Si IV 1403, and the C IV 1548/1551 doublet at a common redshift of
2.609.  At this redshift, the observed T90 (Sato et al., GCN 9263) is 0.33 sec
in the rest frame of the burst.  This burst may be on the short end of the long
GRB population, similar to recent examples such as GRB 090423 (Krimm et al. GCN
9198, Palmer et al. GCN 9204, Thoene et al. GCN 9216, Tanvir et al. GCN 9219,
Krimm et al. GCN 9241), but we encourage further high-energy analyses of this event.


GRB_name: GRB090426A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9265
SUBJECT: GRB090426 Swift/UVOT observations
DATE:    09/04/26 22:13:22 GMT
FROM:    Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>

S. R. Oates (MSSL/UCL) and J. R. Cummings (NASA/UMBC) report on behalf of 
the
Swift/UVOT team:

The Swift/UVOT started settled observations of the burst GRB090426
(Cummings et al. GCN Circ. 9254) with the finding chart (fc) exposure in
white, 89s after the BAT trigger. The afterglow is detected in the white,
b, u and filters and marginally in the v filter at the refined UVOT 
position:

     RA (J2000)  12:36:18.07
    Dec (J2000)  32:59:09.6

with an estimated uncertainty of 0.5 arcsec (radius, 90% confidence).
The lack of detection in the UV filters is consistent with a redshift
of 2.609, which was reported by Chornock et al. (GCN Circ. 9264).

The UVOT magnitudes and upper limits our reported below:

Filter    Tstart(s) Tstop(s)  Exp(s)       Magnitude/3sig UL
###################################################
white (fc)   89      239      147          17.52 +/- 0.03
u (fc)       301     551      246          18.11 +/- 0.08

white        581     600      19           19.10 +/- 0.22
v            630     650      19           19.04 +/- 0.86 (1.3-sigma)
u            556     576      19           18.59 +/- 0.38
b            706     726      19           18.92 +/- 0.36
uvw1         680     2164     175          > 19.92
uvm2         655     2139     175          > 19.63
uvw2         606     2090     136          > 19.82

The values quoted above are in the UVOT photometric system (Poole et al.
2008, MNRAS, 383, 627) and are not corrected for the expected Galactic
extinction corresponding to a reddening of E(B-V)=0.02 mag in the
direction of the burst (Schlegel et al. 1998).


GRB_name: GRB090426A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9266
SUBJECT: GRB 090426: Okayama MITSuME optical observation
DATE:    09/04/26 23:13:33 GMT
FROM:    Michitoshi Yoshida at Okayama Astrophysical Obs  <yoshida@oao.nao.ac.jp>

M. Yoshida, D. Kuroda, K. Yanagisawa, Y. Shimizu, S. Nagayama,
H. Toda (OAO, NAOJ) and N. Kawai (Tokyo Tech) report on behalf
of the MITSuME collaboration:

We detected the optical afterglow of GRB 090426 (Cummings et al.
GCN 9254; Xin et al. GCN 9255; Oates et al. GCN 9265) with the
optical three color (g', Rc and Ic) CCD camera attached to the
MITSuME 50cm telescope of Okayama Astrophysical Observatory.
The observation started on 2009-04-26 12:49:50 UT (63 sec after
the alert). We found the afterglow at the UVOT position of the
GRB (Oates et al. GCN 9265) in all the three bands. It rapidly
faded from 1 min to 2 hours from the burst.

Photometric results listed below. We used GSC2.3 catalog for
flux calibration. We did not apply Galactic extinction to the
following results.

#PDAY      MID-UT   T-EXP    g'  g'_err  Rc   Rc_err  Ic   Ic_err
-----------------------------------------------------------------
0.00108  12:50:20    60.0  17.21  0.15  16.54  0.09  15.95  0.11
0.00436  12:55:04   540.0  17.81  0.08  17.30  0.08  16.90  0.10
0.01198  13:06:03   540.0  19.43  0.31  19.16  0.27  18.30  0.26
0.01116  13:04:52  1500.0  18.58  0.12  18.04  0.09  17.61  0.11
0.06343  14:20:08  3000.0  20.42  0.38  19.86  0.22  19.46  0.35
-----------------------------------------------------------------


GRB_name: GRB090426A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9267
SUBJECT: GRB 090426: Near infrared observation with ISLE at OAO
DATE:    09/04/26 23:50:04 GMT
FROM:    Michitoshi Yoshida at Okayama Astrophysical Obs  <yoshida@oao.nao.ac.jp>

M. Yoshida, D. Kuroda, K. Yanagisawa, Y. Shimizu, S. Nagayama,
H. Toda (OAO, NAOJ) and N. Kawai (Tokyo Tech) report on behalf
of the MITSuME collaboration:

We detected the optical afterglow of GRB 090426 (Cummings et al.
GCN 9254; Xin et al. GCN 9255; Oates et al. GCN 9265; Yoshida et
al. GCN 9266) in near-infrared bands with the near-infrared
camera ISLE attached to the 188cm telescope of Okayama
Astrophysical Observatory.

Photometric results are listed below. We used 2MASS stars in the
FOV of ISLE for flux calibration.

Band   #PDAY     MID-UT   T-EXP   mag   error
----------------------------------------------
J      0.03534  13:39:41  720.0   18.6   0.2
H      0.03960  13:45:49  720.0   18.0   0.2
Ks     0.04336  13:51:13  720.0   17.6   0.2
----------------------------------------------


GRB_name: GRB090426A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9268
SUBJECT: GRB 090426: GROND Observations of the Optical/NIR Afterglow
DATE:    09/04/27 03:28:00 GMT
FROM:    Aybuke Kupcu Yoldas at ESO  <ayoldas@eso.org>

F. Olivares (MPE Garching), A. Kupcu Yoldas (ESO), J. Greiner, A. Yoldas 
(both MPE Garching) report on behalf of the GROND team:

We observed the field of GRB 090424 (Swift trigger 350479; Cummings et 
al., GCN #9254) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 
2008, PASP 120, 405) mounted at the 2.2 m ESO/MPI telescope at La Silla 
Observatory (Chile).

Observations started at 01:08 UT on 27 April, ~12.5 hours after the GRB 
trigger, and are continuing. They are performed at an average seeing of 
1.2 and at an average airmass of 2.5.

We clearly detect the optical/near-infrared afterglow (Cummings et al. 
GCN #9254; Xin et al. #GCN 9255; Oates et al. GCN #9265; Yoshida et al. 
GCN #9266, #9267) in all GROND bands.

Preliminary photometry yields the following AB magnitudes in stacked 
images, obtained using SDSS/2MASS stars as reference:

Filter  Exp[s]  AB Mag  MagErr
----------------------------------------
g'      4x115 22.04 0.03
r'      4x115 21.24 0.24
i'      4x115 21.77 0.11
z'      4x115 21.43   0.09
J  48x10 20.40 0.10 
H  48x10 20.09 0.12
K  48x10 19.83 0.17

Given magnitudes are not corrected for the expected Galactic foreground 
extinction corresponding of E_(B-V)=0.02 mag (Schlegel et al. 1998).

Using these magnitudes combined with the results of previous 
observations (Yoshida et al. GCN #9266) we estimate a simple power law 
decay with an index of ~0.86.


GRB_name: GRB090426A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9269
SUBJECT: GRB 090426: VLT spectroscopy
DATE:    09/04/27 13:43:49 GMT
FROM:    Johan U. Fynbo at U.Copenhagen  <jfynbo@astro.ku.dk>

Christina C. Thoene (INAF/Brera), Daniele Malesani, Johan P. U. Fynbo,
Jens Hjorth (DARK/NBI), Pall Jakobsson (Univ. Iceland), Andrew J. Levan
(Univ. Warwick), Klaas Wiersema, Nial Tanvir (Univ. Leicester), Valerio
D'Elia (INAF/Roma and ASDC), Paul M. Vreeswijk (DARK/NBI), Paolo D'Avanzo
(Univ. Milano-Bicocca & INAF/Brera), Dong Xu (DARK/NBI) report on behalf
of a larger collaboration:

We observed the afterglow of GRB 090426 (Cummings et al., GCN 9254) with
the ESO VLT equipped with the FORS2 spectrograph. Observations were
carried out starting on 2009 Apr 27.048 UT (12.3 hr after the GRB). In the
acquisition image, the afterglow (Cummings et al., GCN 9254) had R ~ 21.65.

Spectra covering the wavelength range 3500-6500 AA were taken, for a total
exposure time of 1 hr. From detection of several absorption features,
including Lyalpha, SiIV 1394, SiIV 1403, CIV 1548/1551, as well as NV
1239/1243, we confirm the redshift z=2.609 derived by Levesque et al.
(GCN 9264).

We note the very low column density (rest EW = 2 AA) of the Lyalpha line,
corresponding to less than 10^19 cm^-2 in HI column density. This
contrasts with the strength of the high-ionization lines.

We acknowledge excellent support from the observing staff at Paranal, in
particular Paul Lynam, Elena Mason, and Jonathan Smoker.


GRB_name: GRB090424A
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9270
SUBJECT: GRB 090424: Suzaku WAM observation of the prompt emission 
DATE:    09/04/27 14:14:03 GMT
FROM:    Yoshitaka Hanabata at Hiroshima U  <hanabata@hep01.hepl.hiroshima-u.ac.jp>

Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa(Hiroshima U.),
K. Kono, E. Sonoda, M. Yamauchi, N. Ohmori, H. Hayashi,
K. Noda, A. Daikyuji, Y. Nishioka (Univ. of Miyazaki),
M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA),
W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda,
T. Sugasahara (Saitama U.), Y. Urata (NCU),
T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo),
K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y. E. Nakagawa,
T. Tamagawa (RIKEN), S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.),
on behalf of the Suzaku WAM team, report:

The long GRB 090424 (Swift/BAT trigger #350311 ; Cannizzo et al., GCN
9223) triggered the Suzaku Wide-band All-sky Monitor (WAM) which
covers an energy range of 50 keV - 5 MeV at 14:12:09.216 UT (=T0).
The observed light curve shows a multi-peaked structure starting at
T0-1 s, ending at T0+12 s, with a duration (T90) of about 4.18
seconds.

The fluence in 100 - 1000 keV was 1.36 (-0.10, +0.28) x10^-5 erg/cm2.
The 1-s peak flux measured from T0 was 12.6 (-0.9, +1.6) photons/cm2/s
in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0-1 s
to T0+12 s is fitted by a power-law with exponential cutoff model:

 dN/dE ~  E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
 alpha       0.92 (-0.77, +0.66), and
 Epeak       250 (-83, +41) keV (chi^2/d.o.f. = 18.9/27).

Due to the high counting rate of this GRB, a 3% systematic error
was added for low energy channels.
We note that this GRB came from the WAM 2 direction,
which has a large uncertainty ~40 % in the absolute flux.


The light curves for this burst are available at:

http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html


GRB_name: GRB090425A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9271
SUBJECT: GRB 090425: Fermi GBM detection
DATE:    09/04/27 16:10:11 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: 

"At 09:03:30.57 UT on 25 April 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090425 (trigger 262343012 / 090425377).
The on-ground calculated location, using the GBM trigger 
data, is RA = 116.1, DEC = 69.9 (J2000 degrees, 
equivalent to 07h 44m, 69d 54'), with an uncertainty 
of 2.9 degrees (radius, 1-sigma containment, 
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 105 degrees.

This burst was also independently detected by INTEGRAL SPI-ACS.

The GBM light curve consists of three widely separated pulses
and has a duration (T90) of about 72 s (8-1000 keV). 
The first two pulses at T0-0.6 s and T0+44 s are weak and
well fit by a simple power law functions with index -1.5 +/- 0.1 
and index -1.7 +/- 0.1 respectively. The third pulse observed at
T0+57 s is strong and structured.
The time-averaged spectrum from T0+57.537 s to T0+80.065 s is 
well fit by  a power law function with an exponential high energy cutoff.  
The power law index is -1.56 +/- 0.04  and the cutoff energy, 
parameterized as Epeak, is 142 +/- 13 keV
(chi squared 570 for 484 d.o.f.).
A Band function fits the spectrum equally well 
(chi squared 566 for 483 d.o.f.) with Epeak= 69 +/- 11 keV, 
alpha = -1.29 +/- 0.11 and beta = -2.03 +/- 0.05. 

The event fluence (8-1000 keV) in this time interval is 
(1.3 +/- 0.2)E-05 erg/cm^2. The 1-sec peak photon flux measured 
starting from T0+57.537 s in the 8-1000 keV band 
is 14.0 +/- 0.3 ph/s/cm^2.

The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090426A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9272
SUBJECT: GRB 090426: Swift/BAT spectral lag results
DATE:    09/04/27 20:43:47 GMT
FROM:    Hans Krimm at NASA-GSFC  <hans.krimm@nasa.gov>

T. N. Ukwatta (GWU/GSFC), N. Gehrels (GSFC), H. A. Krimm
(CRESST/GSFC/USRA), T. Sakamoto (GSFC/UMBC),
S. D. Barthelmy (GSFC), M. Stamatikos (GSFC/ORAU)
(for the Swift-BAT team):

For GRB 090426 (Cummings et al GCN 9254), the spectral lag analysis
of the data from T-1 sec to T+2 sec yields a lag of -6 +/- 45 msec
for the 25-50 to 50-100 keV bands using light curve binnings of
16, 32 and 64 msec. With redshift of 2.609 (Levesque et al GCN 9264)
this lag value transforms to 1.7 +/- 12.5 ms in the GRB
rest frame. The lag is consistent with zero but has relatively large
uncertainty.

Furthermore, the observed T90 (1.2 +/- 0.3 sec; Swift/BAT 15-350 keV,
Sato et al., GCN 9263) and rest frame T90 (0.33 +/- 0.08 sec)
values suggest a short-hard burst. However, the spectral fit
to the BAT data (Sato et al., GCN 9263) indicates a relatively
soft spectrum (a power-law fit to the spectrum gives index
of 1.93 +/- 0.22).

In summary, the observed and rest frame T90 values for GRB 090426
point strongly toward a short-hard burst classification.
The spectral lag is consistent with zero, and the spectrum is
marginally softer than typical for a short-hard burst.
Our conclusion is that this burst could be either short or long,
but the BAT data leads toward a classification as short.


GRB_name: GRB090423A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9273
SUBJECT: GRB 090423: millimeter detection
DATE:    09/04/28 00:29:21 GMT
FROM:    Alberto Castro-Tirado at Inst.de Astro. de Andalucia  <ajct@iaa.es>

A. J. Castro-Tirado (IAA-CSIC Granada), M. Bremer and J.-M. Winters 
(IRAM Grenoble), J. Gorosabel, S. Guziy, M. Jelnek (IAA-CSIC), P. 
Kubnek (GACE, Univ. de Valencia), A. de Ugarte Postigo (ESO Santiago) 
and D. Prez-Ramrez (Univ. de Jan), report:

"Following the detection by Swift of GRB 090423 (Krimn et al. GCNC 
9198), millimeter observations were conducted on Apr 23 & 24 at the 
Plateau de Bure Interferometer. Consistent with the nIR afterglow 
(Tanvir et al. GCNC 9202) we clearly detect a source at 3-mm with a flux 
density of ~0.2 mJy (preliminary) on the combined dataset. Pending of 
confirming its variability we propose this as the likely millimeter 
afterglow  to GRB 090423. Considering the reported redshift values 
around z ~ 8, this is the most distant radio source detected to date.  
Further observations are scheduled. We acknowledge the Bure staff for 
its excellent support."


GRB_name: GRB090423A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9274
SUBJECT: GRB 090423: CARMA mm observations
DATE:    09/04/28 01:57:49 GMT
FROM:    Poonam Chandra at U Virginia/NRAO  <pc8s@virginia.edu>

D. C.-J. Bock (CARMA), P. Chandra (RMC), D. A. Frail (NRAO), and S. R.
Kulkarni (Caltech) report on behalf of a larger collaboration:

"We observed the field of view of GRB 090423 (GCN 9198) with the Combined
Array for Research in Millimeter-Wave Astronomy (CARMA) at a frequency of
92.5 GHz at the mean observation time of 2009 April 25, 0440 UT. We do not
detect mm emission either within the Swift-XRT error circle (GCN 9205) or
at the UKIRT K-band position (GCN 9202). The 3-sigma upper limit on the
flux density of GRB afterglow is 0.7 mJy.

We acknowledge excellent support from the staff and observers at CARMA."


GRB_name: GRB090424A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9275
SUBJECT: GRB 090424: Continued R-band monitoring
DATE:    09/04/28 02:18:53 GMT
FROM:    Myungshin Im at Seoul Nat U  <mim@astro.snu.ac.kr>

  M. Im, Y. Jeon, W. Park, I. Lee (CEOU/Seoul National Univ),
  Y.-B. Jeon (KASI) and Y. Urata (NCU) on behalf of EAFON team.

   We continued our follow-up observation of GRB090424
  (Cannizo et al. GCN 9223) in R using the 1.0m telescope
  at Mt. Lemmon (Arizona, US) operated by the Korea Astronomy
  Space Science Institute.
   The R-band imaging started at 2009 April 27, 02:57:33 UT.
   The mid-point of the R-band obseravation is April 27,
  03:45:21 UT (61.55 hrs after the burst).

   From a stacked image of 20 frames (3 min exp. each),
  we clearly detect the afterglow at R=21.7 +- 0.3 mag.
   Note that this value includes the flux (R ~ 22.2 mag)
  of the host or foreground galaxy at the location of
  the GRB noted by Evans et al. (GCN 9226).
   The trend of the fading, corrected for the galaxy light
  contamination, is consistent with a steep decay of flux
  reported earlier (Im et al. GCN 9253).
   The photometry was calibrated against USNO-B1 stars in
  the vicinity of GRB.

    Mid-point            Rmag      Rmag
   (hrs after burst)               (excluding the galaxy light)
-----------------------------------------------------
     14.97           19.9+-0.14    20.0
     37.45           21.0+-0.17    21.4
     61.55           21.7+-0.30    22.8

   We thank the LOAO operator, I. Baek for her assistance for this
  observation.


GRB_name: GRB090426A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9276
SUBJECT: GRB 090426: R-band limit
DATE:    09/04/28 02:53:10 GMT
FROM:    Myungshin Im at Seoul Nat U  <mim@astro.snu.ac.kr>

  M. Im, Y. Jeon, W. Park, I. Lee (CEOU/Seoul National Univ),
  Y.-B. Jeon (KASI) and Y. Urata (NCU) on behalf of EAFON team.

   We observed GRB090426 (Cummings et al. GCN 9254) in R using
  the 1.0m telescope at Mt. Lemmon (Arizona, US) operated by
  the Korea Astronomy Space Science Institute.
   The R-band imaging started at 2009 April 27, 04:43:19 UT.
   The mid-point of the R-band obseravation is April 27,
  05:06:47 UT (16.3 hrs after the burst).

   From a stacked image of 6 frames (3 min exp. each),
  the afterglow is barely visible in the image where
  the R-band magnitude limit is R = 21.7 at 5-sigma. Therefore,
  we set an upper limit of the R-band magnitude to be R ~ 21.7,
  which should be close to the afterglow brightness.
   The photometry was calibrated against USNO-B1 stars in
  the vicinity of GRB.

   We thank the LOAO operator, I. Baek for her assistance for this
  observation.


GRB_name: GRB090427A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9277
SUBJECT: IPN triangulation of very bright GRB 090427
DATE:    09/04/28 11:00:20 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val@mail.ioffe.ru>

V. Pal'shin, S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets,
P. Oleynik, D. Svinkin, M. Ulanov on behalf of the Konus-Wind and 
Konus-RF teams,

K. Hurley and T. Cline, on behalf of the Mars Odyssey
and Konus GRB teams,

W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on
behalf of the GRS-Odyssey GRB team,

I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin,
on behalf of the HEND-Odyssey GRB team,

M. Marisaldi, G. Di Cocco, F. Fuschino, M. Galli, C. Labanti,
on behalf of the AGILE MCAL team,

E. Del Monte, E. Costa, I. Donnarumma, Y. Evangelista, M. Feroci,
I. Lapshov, F. Lazzarotto, L. Pacciani, M. Rapisarda, P. Soffitta,
on behalf the SuperAGILE team,

A. von Kienlin, G. Lichti, and A. Rau, and K. Hurley on behalf of the
INTEGRAL SPI-ACS team report:

Konus-Wind, Konus-RF, Mars-Odyssey (GRS and HEND), SuperAGILE, 
AGILE-MCAL, and INTEGRAL-SPI-ACS observed the bright GRB 090427 at about 
84387 s UT (23:26:27). The burst was outside the coded field of view of 
the SuperAGILE.

The burst light curve shows a multipeaked structure with a duration of
~15 sec.

We have triangulated it to the following 3-sigma error box:
-----------------------------------------------
    RA(2000), deg              Dec(2000), deg
-----------------------------------------------
Center:
  235.931 (15h 43m 43s)   -13.498 (-13d 29' 53")
Corners:
  236.026 (15h 44m 06s)   -12.481 (-12d 28' 52")
  236.183 (15h 44m 44s)   -12.470 (-12d 28' 12")
  235.820 (15h 43m 17s)   -14.521 (-14d 31' 16")
  235.658 (15h 42m 38s)   -14.542 (-14d 32' 30")
-----------------------------------------------

The error box area is 0.313 sq. deg.
This error box may be improved.

Preliminary analysis of the Konus-Wind data yields
a burst fluence of ~1x10^-4 erg/cm2 (in the 20 keV - 8 MeV range),
and an Epeak of the time-integrated spectrum of ~750 keV.

IPN triangulation map is available at 
http://www.ioffe.ru/LEA/GRBs/GRB090427_T84392/IPN/


GRB_name: GRB090424A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9278
SUBJECT: GRB 090424 : Multiband Optical observation from Nainital
DATE:    09/04/28 19:35:04 GMT
FROM:    Rupak Roy at ARIES  <rupakroy1980@gmail.com>

Rupak Roy, Brajesh Kumar, S. B. Pandey and Brijesh Kumar (ARIES,
NainiTal, India, on behalf of larger Indian GRB collaboration).
We performed BVRI photometric observation of Swift GRB 090424
(Cannizzo, J. K. et al., GCN 9223) on 24th April, 2009 at 16.7 hrs UT,
under moderate sky conditions,
using 1.04 m Sampurnanand Optical telescope at ARIES, Nainital. The
same field was again observed on next day, about 29 hrs after the
burst in R and I bands.
Fading nature of the afterglow is clearly visible in all bands. The
R_c and I_c band magnitudes of OT, with respect to nearby USNO-B1
stars, are 18.5 +/- 0.05 and 17.8 +/-
0.06 respectively, measured 2.67 hrs after the burst. Further analysis
is under progress.


GRB_name: GRB090423A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9279
SUBJECT: GRB 090423:  pseudo burst at z=1 and its relation to GRB 080913 
DATE:    09/04/29 00:10:01 GMT
FROM:    Binbin Zhang at UNLV  <zbb@physics.unlv.edu>

Bin-Bin Zhang and Bing Zhang (University of Nevada Las Vegas) report:

GRB 090423 is a second, high-z, intrinsically short GRB after GRB 
080913. Following  the similar procedure discussed in Zhang, B et al 
2009, http://arxiv.org/abs/0902.2419 ,  we have simulated a pseudo GRB 
by shifting GRB 090423 to z=1. The following three factors, i.e, 
specific flux (f_\nu) amplification due to a smaller luminosity 
distance, blue-shift of spectrum, and temporal compression of the 
lightcurve (de-dilation), have been considered. We notice that there is 
an early X-ray flare in GRB 090423 (again similar to GRB 080913), which 
should be harder and observable by BAT if it were at z=1. Following the 
similar procedure described in Zhang et al. (2009), we manipulate the 
XRT data of GRB 090423 to simulate the BAT band extended emission of the 
pseudo  burst. The constructed BAT band lightcurve of the pseudo GRB at 
z=1 is shown in the  figure at 
http://grb.physics.unlv.edu/gcns/090423/pseudo.jpg . This psuedo burst 
appears as a short duration GRB with extended emission.

On the other hand, both high-z GRBs have high isotropic luminosity and 
energy, which make them following the Amati/Yonetoku correlation defined 
by GRBs that are of the  massive star origin (Type II or long 
population). Although it is possible to have NS-NS and NS-BH mergers 
(Type I or short population) at such a high-z (Belczynski et al. 2009),  
the difficulty is to have two such energetic merger events at high-z. 
The Type I model  has difficulty to accommodate both low-z, low-L Type I 
events and these events in terms of luminosity function (Zhang et al. 
2009). Based on the multiple criteria analysis, we cannot address the 
physical category of GRB 090423 and GRB 080913 using more definite 
criteria (e.g. SN association, host galaxy property, etc). On the other 
hand, one can use less definite criteria (Amati/Yonetoku relation and 
energetics)  to judge that both bursts are Type II (massive star 
collapse) candidates. A judging flow chart using Fig. 8 of Zhang et al. 
(2009) is posted at  
http://grb.physics.unlv.edu/gcns/090423/flowchart.jpeg .  We also 
noticed the interesting discussions by Krimm et al. (GCN 9241) and  Nava 
et al. (GCN 9235), which are broadly consistent with our conclusion here.

Finally, using the three samples (Type II Gold,  Type I Gold, and Other 
Short/Hard)  defined in Zhang et al. (2009), we plot the intrinsic 
duration (T_{90}/(1+z)) as a function of z (see 
http://grb.physics.unlv.edu/gcns/090423/t90z.png ). It is interesting to 
note that the two high-z bursts are intrinsically shorter than the  
majority of Type II GRBs. If these observations persist in the future, 
it may suggest  an intrinsic trend of short duration for Type II GRBs at 
high-z.

This message can be cited.


GRB_name: GRB090429A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9280
SUBJECT: GRB 090429: Swift detection of a burst
DATE:    09/04/29 05:29:46 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

C. B. Markwardt (CRESST/GSFC/UMD), S. D. Barthelmy (GSFC),
P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC),
K. L. Page (U Leicester), D. M. Palmer (LANL),
B. A. Rowlinson (U Leicester), M. H. Siegel (PSU),
M. Stamatikos (NASA/ORAU) and T. N. Ukwatta (GSFC/GWU) report on
behalf of the Swift Team:

At 04:53:39 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090429 (trigger=350853).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 90.559, -52.386 which is 
   RA(J2000) = 06h 02m 14s
   Dec(J2000) = -52d 23' 09"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a broad peak
with a duration of about 25 sec.  The peak count rate
was ~700 counts/sec (15-350 keV), at ~5 sec after the trigger. 

The XRT began observing the field at 04:54:38.0 UT, 58.1 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 90.5548, -52.3855 which is equivalent to:
   RA(J2000)  = 06h 02m 13.15s
   Dec(J2000) = -52d 23' 07.8"
with an uncertainty of 5.1 arcseconds (radius, 90% containment). This
location is 9.4 arcseconds from the BAT onboard position, within the
BAT error circle. No event data are yet available to determine the
column density using X-ray spectroscopy. 


UVOT took a finding chart exposure of 150 seconds with the White filter
starting 66 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.06. 




Because this burst was detected as part of the sub-threshold program
(see GCN 8943) with a BAT image significance of only 5.64 sigma,
GCN notices were not generated until the source was confirmed
using XRT data. 

Burst Advocate for this burst is C. B. Markwardt (Craig.Markwardt AT nasa.gov). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090429B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9281
SUBJECT: GRB 090429B: Swift detection of a burst
DATE:    09/04/29 05:47:53 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

T. N. Ukwatta (GSFC/GWU), S. D. Barthelmy (GSFC),
P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC),
C. B. Markwardt (CRESST/GSFC/UMD), K. L. Page (U Leicester),
D. M. Palmer (LANL), B. A. Rowlinson (U Leicester),
M. H. Siegel (PSU), M. Stamatikos (NASA/ORAU) and L. Vetere (PSU)
report on behalf of the Swift Team:

At 05:30:03 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090429B (trigger=350854).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 210.704, +32.163 which is 
   RA(J2000) = 14h 02m 49s
   Dec(J2000) = +32d 09' 48"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed three peaks
with a duration of about 5 sec.  The peak count rate
was ~4000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 05:31:50.0 UT, 106.6 seconds after
the BAT trigger. Using promptly downlinked data we find an
uncatalogued X-ray source with an enhanced position: RA, Dec 210.6670,
32.1707 which is equivalent to:
   RA(J2000)  = 14h 02m 40.09s
   Dec(J2000) = +32d 10' 14.6"
with an uncertainty of 2.3 arcseconds (radius, 90% containment). This
location is 116 arcseconds from the BAT onboard position, within the
BAT error circle. This position may be improved as more data are
received; the latest position is available at
http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of
1.2e+20 cm^-2 (Kalberla et al. 2005). 

UVOT took a finding chart exposure of 150 seconds with the White 
filter  starting 99 seconds after the BAT trigger. No credible 
afterglow candidate has  been found in the initial data products. The
 2.7'x2.7' sub-image covers 25% of  the BAT error circle but does not 
overlap the XRT error circle. The typical 3-sigma upper limit has 
been about 19.6 mag. The 8'x8' region for the list of sources 
generated on-board covers 100% of the BAT error circle and 100% of
the XRT error circle. The list of  sources is typically complete to
about 18 mag. No correction has been  made for the expected
extinction corresponding to E(B-V) of  0.01. 

Burst Advocate for this burst is T. N. Ukwatta (tilan.ukwatta AT gmail.com). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090429B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9282
SUBJECT: GRB 090429B: Super-LOTIS early observations
DATE:    09/04/29 06:40:06 GMT
FROM:    Adria C. Updike at Clemson U  <aupdike@clemson.edu>

Adria C. Updike (Clemson University), G. Grant Williams (MMTO
Observatory), Peter A. Milne (Steward Observatory), and Dieter H. Hartmann
(Clemson University) report:

The 0.6m Super-LOTIS telescope at Kitt Peak National Observatory began
observing the field of GRB 090429B 40 seconds after the trigger (Ukwatta
et al., GCN 9281) under good conditions.  Observations consisted sets of
10, 20, and 60 second exposures.  No new sources are found in the XRT
error circle.
The results of the stacked exposures are given below; time is given in
seconds after the trigger (midtime of stack).  Magnitudes were determined
relative to the USNO B1.0 catalog.


Band    Exposures      Time       Mag
-------------------------------------------
R        5 x 10sec     80        > 17
R       10 x 60sec    580        > 19


Observations are continuing.  This message may be cited.


GRB_name: GRB090429B
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9283
SUBJECT: GRB 090429B: GROND Observations
DATE:    09/04/29 07:58:36 GMT
FROM:    Aybuke Kupcu Yoldas at ESO  <ayoldas@eso.org>

F. Olivares (MPE Garching), A. Kupcu Yoldas (ESO), J. Greiner, T. 
Kruehler, A. Yoldas (both MPE Garching) report on behalf of the GROND team:

We observed the field of GRB 090429B (Swift trigger 350854; Ukwatta et 
al., GCN #9281) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 
2008, PASP 120, 405) mounted at the 2.2 m ESO/MPI telescope at La Silla 
Observatory (Chile).

Observations started at 05:43 UT, ~13 minutes after the GRB trigger and 
continued until the source reached the 20 deg horizon limit. They are 
performed at an average seeing of 1.2 and at an average airmass of 2.5.

We do not detect any source within the Swift-XRT error circle reported 
by Ukwatta et al. (GCN #9281) down to the following limits (based on 4 
minutes of exposure time, all in AB system):

g' > 23.4 mag
r' > 23.3 mag
i' > 22.4 mag
z' > 21.8 mag
J > 21.5 mag
H > 20.2 mag
K > 19.6 mag

Quoted upper limits have been derived using USNO and 2MASS field stars
as reference.


GRB_name: GRB090429B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9284
SUBJECT: GRB 090429B: VLT upper limits
DATE:    09/04/29 08:30:22 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>

Paolo D'Avanzo (Univ. Milano-Bicocca & INAF/Brera), Andrew J. Levan 
(Univ. Warwick), Daniele Malesani (DARK/NBI), Christina C. Thoene 
(INAF/Brera), Johan P. U. Fynbo, Jens Hjorth (DARK/NBI), Nial Tanvir 
(Univ. Leicester), report on behalf of a larger collaboration:

We observed the field of GRB 090429B (Ukwatta et al. GCN 9281) with the 
ESO-VLT in imaging mode with the FORS2 camera. Observations started 
about 1 hr after the burst. In our stacked images, no afterglow is 
detected down to the following 3sigma limits:

R > 25.3
z > 23.5

Photometry has been calibrated against USNOB1 catalogue and the SDSS.

We acknowledge support from the Paranal staff, in particular E. Mason 
and P. Lynam.


GRB_name: GRB090426A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9285
SUBJECT: GRB 090426: YNAO-GMG observations 
DATE:    09/04/29 09:10:30 GMT
FROM:    Jirong Mao at Yunnan Obs  <jirongmao@ynao.ac.cn>

J. Mao (YNAO & INAF-OAB), G. Cha and J. Bai (YNAO) report on behalf of the GMG group:

We observed the optical counterpart of GRB 090426 (Cummings et al., GCN 9254) using 
one 2.4-m telescope located at Gao-Mei-GU (GMG) about 2 hours after the trigger and 
otained the following magnitudes: 

Start UT  Exposure Filter  Mag   Err
-------------------------------------
14:07:59  20 min     I    19.18  0.06
14:52:19  20 min     R    20.29  0.02   
15:49:27  20 min     V    20.97  0.04

and calibration was processed by a nearby SDSS star in the image. 

The telescope is charged by Yunnan Observatory (YNAO), Chinese Academy of Sciences.   

This message might be cited. 
 


GRB_name: GRB090429B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9286
SUBJECT: GRB090429B: Gemini-N infrared IR candidate
DATE:    09/04/29 10:45:17 GMT
FROM:    Antonino Cucchiara at PSU  <cucchiara@astro.psu.edu>

A. Cucchiara (PSU), A. Levan (U. Warwick), N. Tanvir (U. Leicester),
D. B. Fox (PSU) and E. Berger (Harvard U.) report:

"On April 29.35 UT we imaged the field of Swift GRB 090429 (Ukwatta et
al., GCN 9281) with NIRI on the Gemini-North telescope.  We obtained
images in J,H and K for a total exposure time of 9, 4.5 and 9 minutes
respectively.
In the coadded images we identify a possible IR counterpart inside the
XRT error circle at the coordinates:

RA (J2000): 14:02:40.05
Dec (J2000): +32:10:14.32

with an uncertainty of 0.5".

The estimated magnitude are:

J = 21.79 +- 0.1
H = 20.08 +- 0.05
K = 19.15 +- 0.03

These values are calibrated using the 2MASS star at RA=14:02:42.20,
Dec= +32:10:50.36.

Although variability remains to be confirmed, the red J-H colour,
coupled with the relatively blue (H-K) is suggestive of a break.
Although this may be caused by dust the lack of apparent excess N_H in
the X-ray spectrum (GCN 9281) suggests this may not be the case.
Hence GRB 090429B should be considered a high-z candidate."
 
We thank the Gemini-N staff for the support in performing this
observations, in particular Scott Fisher and Kathy Roth."


GRB_name: GRB090429A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9287
SUBJECT: GRB 090429A - Correction to XRT position
DATE:    09/04/29 11:35:56 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:

The onboard XRT position for GRB 090429A (Markwardt et al. GCN. Circ 
9280) delivered as an XRT position notice and given in GCN 9280 was 
incorrect. Inspection of the images reveals a cosmic ray 52 arcsec from 
the GRB which affected the onboard centroid.

The correct position of the XRT afterglow is: RA, Dec= 90.5568, -52.3886
which is equivalent to:

RA(J2000)  = 06 02 13.63
Dec(J2000) = -52 23 18.9

with an uncertainty of 4.8 arcsec (radius, 90% confidence).

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090429B
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9288
SUBJECT: GRB 090429B: Enhanced Swift-XRT position
DATE:    09/04/29 11:44:00 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 862 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 090429B, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 210.66707, +32.17072 which is equivalent
to:

RA (J2000): 14h 02m 40.10s
Dec (J2000): +32d 10' 14.6"

with an uncertainty of 1.8 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, arXiv:0812.3662).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB090429A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9289
SUBJECT: GRB 090429A: Swift-BAT refined analysis
DATE:    09/04/29 11:56:38 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), A. M. Parsons (GSFC),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-61 to T+302 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090429A (trigger #350853)
(Markwardt, et al., GCN Circ. 9280).  The BAT ground-calculated position is
RA, Dec = 90.573, -52.389 deg, which is 
   RA(J2000)  =  06h 02m 17.5s 
   Dec(J2000) = -52d 23' 19.0" 
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.
 
The mask-weighted light curve shows a relatively smooth structure
with a couple overlapping peaks starting at ~T-12 sec and peaking at T_zero.
The main peak ends around T+40 sec with a long weak tail extending out
to ~T+200 sec.  T90 (15-350 keV) is 188 +- 37 sec (estimated error
including systematics).
 
The time-averaged spectrum from T-10.8 to T+203.0 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.55 +- 0.22.  The fluence in the 15-150 keV band is 1.0 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T-0.35 sec in the 15-150 keV band
is 0.6 +- 0.1 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/350853/BA/


GRB_name: GRB090429B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9290
SUBJECT: GRB 090429B: Swift-BAT refined analysis
DATE:    09/04/29 12:09:35 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

M. Stamatikos (GSFC/ORAU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL),
A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090429B (trigger #350854)
(Ukwatta, et al., GCN Circ. 9281).  The BAT ground-calculated position is
RA, Dec = 210.672, 32.167 deg, which is 
   RA(J2000)  =  14h 02m 41.2s 
   Dec(J2000) = +32d 10' 02.0" 
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 84%.
 
The mask-weighted light curve shows a main peak starting at ~T-4 sec,
peaking at ~T-0.1 sec, and ending around T+3 sec.  There are two very
weak peaks: ~T+30 to ~T+70 sec, and ~T+100 to ~T+110 sec.
T90 (15-350 keV) is 5.5 +- 1.0 sec (estimated error including systematics).
 
The time-averaged spectrum from T-4.5 to T+2.4 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 0.47 +- 0.77, 
and Epeak of 42.1 +- 5.6 keV (chi squared 29.6 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 3.1 +- 0.3 x 10^-7 erg/cm2
and the 1-sec peak flux measured from T-0.28 sec in the 15-150 keV band is
1.6 +- 0.2 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.96 +- 0.13 (chi squared 45.3 for 57 d.o.f.).  All the quoted errors
are at the 90% confidence level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/350854/BA/


GRB_name: GRB090429B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9291
SUBJECT: GRB 090429B: RIMOTS optical upper limits
DATE:    09/04/29 14:05:00 GMT
FROM:    Kenta Kono at Miyazaki U  <kenta0514@astro.miyazaki-u.ac.jp>

K.Kono, E.Sonoda, N.Ohmori, H.hayasi,
K.Noda, A.Daikyuji, Y.Nisioka, M.Yamauchi
(University of Miyazaki)

We have observed the field covering the error circle of
GRB09042 (Swift trigger 350854, GCN 9281, T. N. Ukwatta et al.)
with the unfiltered CCD camera on the 30-cm telescope
at University of Miyazaki.
The observation was started 11:29:13 UT, about 6.0 hr
after the Swift trigger time.

We have compared our data of 30 sec exposures
with the USNO-A2.0 catalog,
There is no new source at the reported position.
(GCN 9281, T. N. Ukwatta et al. GCN 9288, A.P. Beardmore et al.
 GCN 9290, M. Stamatikos et al.)

the upper limits are as follows:
--------------------------------------------------------------
Start(UT)   End(UT)    Num. of frames    Limit (mag.)
--------------------------------------------------------------
11:29:13    11:29:33          1            16.4
11:29:13    12:04:10         28            17.9
---------------------------------------------------------------


GRB_name: GRB090426A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9292
SUBJECT: GRB 090426: GAO 150cm telescope Optical Observation
DATE:    09/04/29 14:27:50 GMT
FROM:    Kenzo Kinugasa at Gunma Astro. Obs/Japan  <kinugasa@astron.pref.gunma.jp>

K. Kinugasa, S. Honda, O. Hashimoto, H. Takahashi, H. Taguchi
 (Gunma Astronomical Observatory) report:

 The position of GRB 090426 (Cummings et al., GCN 9254) was
observed with the 150 cm telescope of Gunma Astronomical
Observatory. Starting at 13:20 and 13:48 UT (0.52 and 1.0 hours
 after the trigger), Ic and Rc frames were acquired for sets of
3 x 3-min and  5 x 5-min exposures, respectively.

 We detected the optical counterpart (e.g., Xin et al., GCN 9255;
 Oates et al., GCN 9265) in all frames. We estimated the Rc and Ic
magnitudes relative to USNO-B1.0 R2 and I, respectively.

mid-UT     exp        mag.
-----------------------------------
13:24:45   3x3min     Ic=18.5+-0.3
14:03:58   5x5min     Rc=19.9+-0.1
-----------------------------------


GRB_name: GRB090418A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9293
SUBJECT: GRB 090418A BVRcIc field calibration
DATE:    09/04/29 14:49:54 GMT
FROM:    Arne A. Henden at AAVSO  <arne@aavso.org>

A. Henden (AAVSO), J. Gross (SRO), B. Denny (DC-3),
D. Terrell (SwRI), and W. Cooney (SRO) report:

We have performed an all-sky calibration of the field
for the GRB090418A afterglow reported by Chornock,
et al. (GCN 9148) using the Sonoita Research
Observatory (SRO) 35cm telescope in southern
Arizona.  Two photometric nights were used for the
calibration, with multiple Landolt fields observed
during each night along with an extinction
star for the calibration.  The calibration file has
a limiting magnitude around V=18, with good standards
brighter than V=16.  The file is available at
ftp://ftp.aavso.org/public/calib/grb/grb090418a.dat

We estimate the external zeropoint error of this calibration
to be about 0.02mag.  In particular, the star used by
Henden, et al. (GCN 9211) as a comparison star:
17:57:42.53 +33:25:47.2 J2000
has an R magnitude of 12.82, so all of the photometry in
GCN 9211 should be adjusted 0.30mag brighter.

Our system is available for any other bright UBVRI
calibrations (4<V<19) for this field or any
other field; contact the first author for such requests.

The AAVSO thanks the Curry Foundation for their continued support of the
AAVSO International High Energy Network,


GRB_name: GRB090428A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9294
SUBJECT: GRB 090428: Fermi GBM detection
DATE:    09/04/29 15:20:35 GMT
FROM:    Elisabetta Bissaldi at MPE  <ebs@mpe.mpg.de>

Elisabetta Bissaldi (MPE) reports on behalf of the Fermi GBM Team:


"At 10:34:38.46 UT on 28 April 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090428 (trigger 262607680 / 090428441).
The on-ground calculated location, using the GBM trigger
data, is RA = 212.4, DEC = +37.3 (J2000 degrees,
equivalent to 14h 10m, 37d 18'), with an uncertainty
of 3.5 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).

The angle from the Fermi LAT boresight is 96 degrees.

The GBM light curve consists of two peaks
with a duration (T90) of about 8 s (8-1000 keV).
The time-averaged spectrum from T0-0.51 s to T0+2.04 s is
adequately fit by a power law function with an exponential
high energy cutoff.  The power law index is -0.59 +/- 0.16
and the cutoff energy, parameterized as Epeak, is
97 +/- 7 keV (chi squared 471 for 485 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(9.9 +/- 1.4)E-07 erg/cm^2. The 128-msec peak photon flux measured
starting from T0+1.4 s in the 8-1000 keV band
is 12.3 +/- 1.9 ph/s/cm^2.

A Band function fits the spectrum equally well
(chi squared 468 for 484 d.o.f.) with Epeak = 85 +/- 10 keV,
alpha= -0.40 +/- 0.25 and beta = -2.7 +/- 0.4.


The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090428B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9295
SUBJECT: GRB 090428B: Fermi GBM detection
DATE:    09/04/29 15:22:36 GMT
FROM:    Elisabetta Bissaldi at MPE  <ebs@mpe.mpg.de>

Elisabetta Bissaldi (MPE) reports on behalf of the Fermi GBM Team:


"At 13:15:11.06 UT on 28 April 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090428B (trigger 262617313 / 090428552).
The on-ground calculated location, using the GBM trigger
data, is RA = 0.8, DEC = +6.5 (J2000 degrees,
equivalent to 00h 03m, 06d 30'), with an uncertainty
of 4.4 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).

The angle from the Fermi LAT boresight is 101 degrees.

The GBM light curve consists of a broad single peak
with a duration (T90) of about 30 s (8-1000 keV).
The time-averaged spectrum from T0-9.2 s to T0+15.3 s is
adequately fit by a power law function with an exponential
high energy cutoff. The power law index is -1.86 +/- 0.07
and the cutoff energy, parameterized as Epeak,
is 65 +/- 16 keV (chi squared 279 for 241 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(5.2 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+3.1 s in the 8-1000 keV band
is 10.1 +/- 0.7 ph/s/cm^2.

A Band function fits the spectrum equally well
(chi squared 278 for 240 d.o.f.) with Epeak = 53 +/- 19 keV,
alpha = -1.81 +/- 0.13 and beta = -2.17 +/- 0.21.


The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090427A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9296
SUBJECT: Konus-Wind observation of very bright GRB 090427
DATE:    09/04/29 16:16:22 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val@mail.ioffe.ru>

S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P.
Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind
team, report:

The very bright GRB 090427 localized by IPN (Pal'shin et al., GCN
9277) triggered Konus-Wind at T0=84392.051 s UT (23:26:32.051).

As observed by Konus-Wind the burst
had a fluence of (1.03 +/- 0.05)x10^-4 erg/cm2,
and a 16-ms peak flux measured from T0+9.200 s
of (1.10 +/- 0.13)x10^-4 erg/cm2/s
(both in the 20 keV - 8 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+17.920 s) can be fitted (in the 20 keV - 8 MeV
range) by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -1.31 +/- 0.04,
and Ep = 751(-67, +78) keV (chi2 = 90.5/85 dof).
Fitting by GRB (Band) model yields the same alpha and Ep,
and only an upper limit on the high energy
photon index: beta < -2.8 (chi2 = 90.4/84 dof).
All the quoted errors are at the 90% confidence level.

The Konus-Wind light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB090427_T84392/


GRB_name: GRB090429A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9297
SUBJECT: GRB 090429A: Enhanced Swift-XRT position
DATE:    09/04/29 18:20:30 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 945 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 090429A, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 90.55469, -52.38758 which is equivalent
to:

RA (J2000): 06h 02m 13.13s
Dec (J2000): -52d 23' 15.3"

with an uncertainty of 3.2 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, arXiv:0812.3662).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB090429B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9298
SUBJECT: GRB 090429B: Swift XRT refined analysis
DATE:    09/04/29 20:14:12 GMT
FROM:    Antonia Rowlinson at U.of Leicester  <bar7@star.le.ac.uk>

A. Rowlinson (U. Leicester) and T. N. Ukwatta (GSFC/GWU) report on
behalf of the Swift-XRT team:

We have analysed 8.9 ks of XRT data for GRB 090429B (Ukwatta et al. GCN
Circ. 9281), from 104 s to 29.9 ks after the BAT trigger. The data are
entirely in Photon Counting (PC) mode. The enhanced XRT position for
this burst was given by Beardmore et al. (GCN. Circ 9288).

The light curve initially shows a slow rise, which can be fitted with a
power-law of index 0.89 (+0.36, -0.46). At around T+642 s the light
curve breaks to a power-law decay, with index 1.20 (+0.11, -0.10).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.00 (+0.15, -0.24). The
best-fitting absorption column is 10.0 (+4.2, -5.3) x 10^20, in excess
of the Galactic value of 1.2 x 10^20 cm^-2 (Kalberla et al. 2005). The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 3.8 x 10^-11 (4.9 x 10^-11) erg cm^-2
count^-1.

If the light curve continues to decay with a power-law decay index of
1.20, the count rate at T+24 hours will be 0.0014 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.3 x
10^-14 (6.9 x 10^-14) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00350854.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090426B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9299
SUBJECT: GRB 090426B: Fermi GBM detection/observation
DATE:    09/04/29 20:19:46 GMT
FROM:    Michael S. Briggs at UAH and MSFC  <michael.briggs@nasa.gov>

M. S. Briggs (UAH) reports on behalf of the Fermi GBM Team:

"At 01:35:35.23 UT on 26 April 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090426B (trigger 262402537 / 090426066).

The on-ground calculated location, using the GBM trigger
data, is RA = 17.6, DEC = -19.2 (J2000 degrees,
equivalent to 01 h 10 m, -19 d 12'), with an uncertainty
of 18.1 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 56 degrees.

The GBM light curve shows a peak followed by a tail with a
T90 duration of 3.8 s (8-1000 keV).   The time-averaged
spectrum from T0-2.048 s to T0+3.072 s is well fit by a
simple power law function with index -1.60 +/- 0.08.

The event fluence (8-1000 keV) in this time interval is
(5.2 +/- 1.2)E-7 erg/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090426C
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9300
SUBJECT: GRB 090426C: Fermi GBM detection
DATE:    09/04/29 20:21:03 GMT
FROM:    Alexander van der Horst at NASA/MSFC  <Alexander.J.VanDerHorst@nasa.gov>

A.J. van der Horst (NASA/MSFC/ORAU) reports on behalf of the
Fermi GBM Team:

"At 16:33:49.27 UT on 26 April 2009, the Fermi Gamma-ray Burst Monitor
(GBM) triggered and located GRB 090426C (trigger 262456415 / 090426.690).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 82.7, Dec = -9.7 (J2000 degrees, equivalent to
J2000 5h31m, -9d40'), with a statistical uncertainty of 2.0 degrees
(radius, 1-sigma containment, statistical only; there is additionally
a systematic error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 69 degrees.

The GBM light curve consists of one main pulse, with a duration of ~12
seconds. The time-averaged spectrum from T0-0.4 to T0+9.9 s is adequately
fit by a power law with an exponential high-energy cutoff, but can also
be well fit by a Band function, although the beta value for the latter
is poorly constrained. For the power law with exponential cutoff, the
index is -1.31 +/- 0.09 and the cutoff energy, parameterized as Epeak,
is 351 +150/-81 keV. For the Band function, alpha is -1.29 +/- 0.11,
beta is -1.98 +0.17/-0.64 and Epeak is 295 +166/-83.
The fluence (8-1000 keV) in this time interval is (3.1 +/- 0.2)E-6 
erg/cm^2.
The 1-sec peak photon flux measured starting from T0+0.7s in the
8-1000 keV band is 6.8 +/- 0.7 ph/s/cm^2.

The temporal and spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090427B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9301
SUBJECT: GRB 090427B: Fermi GBM detection
DATE:    09/04/29 20:24:39 GMT
FROM:    Michael S. Briggs at UAH and MSFC  <michael.briggs@nasa.gov>

M. S. Briggs (UAH) reports on behalf of the Fermi GBM Team:

"At 15:27:00.86  UT on 27 April 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090427B (trigger 262538822 / 090427644).

The on-ground calculated location, using the GBM trigger
data, is RA = 210.0, DEC = -45.7 (J2000 degrees,
equivalent to 14 h 00 m, -45 d 42'), with an uncertainty
of 11.8 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 14 degrees.

The GBM light curve consists of a single peak
with a duration about 7 s (8-1000 keV).
The time-averaged spectrum from T0-4.096 s to T0+2.048 s is
well fit by a simple power law function with
index -1.1 +/- 0.1.

The event fluence (8-1000 keV) in this time interval is
(8.0 +/- 0.5)E-7 erg/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090427C
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9302
SUBJECT: GRB 090427C: Fermi GBM detection
DATE:    09/04/29 20:28:46 GMT
FROM:    Michael S. Briggs at UAH and MSFC  <michael.briggs@nasa.gov>

M. S. Briggs (UAH) reports on behalf of the Fermi GBM Team:

"At 16:30:23.81 UT on 27 April 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090427C (trigger 262542625  / 090427688).

The on-ground calculated location, using the GBM trigger
data, is RA = 356.2, DEC = -34.6 (J2000 degrees,
equivalent to 23 h 45 m, -34 d 36'), with an uncertainty
of 5.8 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 81 degrees.

The GBM light curve shows two peaks and has a
duration (T90) of about 12.5 s (8-1000 keV).
The time-averaged spectrum from T0-2.048 s to T0+12.288 s is
well fit by a power law function with an exponential
high energy cutoff.  The power law index is 0.35 +/- 0.16 and
the cutoff energy, parameterized as Epeak, is 75 +/- 3 keV.

The event fluence (8-1000 keV) in this time interval is
(1.6 +/- 0.2)E-6 erg/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090429A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9303
SUBJECT: GRB 090429A: GROND upper limits 
DATE:    09/04/30 09:16:41 GMT
FROM:    Thomas Kruehler at MPE/MPI  <kruehler@mpe.mpg.de>

F. Olivares, T. Kruehler, J. Greiner (all MPE) report on behalf of the 
GROND team:

We observed the field of GRB 090429A (Swift trigger 350853, Markwardt et 
al.,GCN #9280) simultaneously in g'r'i'z'JHK with GROND mounted at the 2.2m 
ESO/MPI telescope at La Silla Observatory (Chile).

Observations started on 30 Apr. 2009 at 01:05 UT, 20.2 h after the burst, 
and consisted of a set of images with a total integration time of 28 min in 
JHK and 32 min in g'r'i'z'.

In stacked images we do not detect any object inside the enhanced XRT 
errorcircle (Evans et al., GCN #9297) down to the following AB magnitudes:

g' > 23.4
r' > 23.3
i' > 22.6
z' > 22.2
J > 21.8
H > 20.7
K > 20.0

These upper limits have been obtained using 2MASS field stars and the GROND 
zeropoints as reference.


GRB_name: GRB090429A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9304
SUBJECT: GRB 090429A: Swift-XRT refined analysis
DATE:    09/04/30 10:39:40 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

P.A. Evans (U. Leicester) and C. B. Markwardt (CRESST/GSFC/UMD) report
on behalf of the Swift-XRT team:

We have analysed 6 ks of XRT data for GRB 090429A (Markwardt et al. GCN
Circ. 9280). The first observation comprises a continuous observation
from T0+64 s to T0+255 s  with the data  entirely in Windowed Timing
(WT) mode. The second observation covers the range T0+35 to T0+64 ks,
and contains 5.8 ks of Photon Counting (PC) mode data. The enhanced XRT
position for this burst was given by Evans et al. (GCN. Circ 9297).

The first observation shows a number of flares superimposed on a short,
initial rise which breaks at T0+100s to a power-law decay with index 2.7
(+0.3, -0.2). The later PC mode data lie orders of magnitude above the
extrapolation of this decay; the addition of a break around T0+1 ks to a
decay with power-law index 0.56 (+0.12, -0.06) produces a good fit to
the data. Due to the large observing gap the behaviour of the light
curve in the interval T0+255 s to T0+35 ks is unknown; if it is more
complex than the simple behaviour we have modelled the final decay index
could differ significantly from the 0.56 (+0.12, -0.06) value we obtained.

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.0 (+1.0, -0.7). The
best-fitting absorption column is 1.20 (+2.36, -0.77) x 10^21 cm^-2,
consistent with the Galactic value of 4.2 x 10^20 cm^-2 (Kalberla et al.
2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 3.8 x 10^-11 (5.0 x 10^-11) erg
cm^-2 count^-1.

If the light curve continues to decay with a power-law decay index of
0.56, the count rate at T+48 hours will be 5.9 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.2 x
10^-13 (2.9 x 10^-13) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00350853.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090424A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9305
SUBJECT: GRB 090424: YNAO-GMG observations
DATE:    09/04/30 11:10:12 GMT
FROM:    Jirong Mao at Yunnan Obs  <jirongmao@ynao.ac.cn>

J. Mao (YNAO & INAF-OAB), G. Cha and J. Bai (YNAO) report on behalf of the GMG group: 
 
We observed the optical counterpart of GRB 090424 (Cannizzo et al., GCN 9223) using 
one 2.4-m telescope located at Gao-Mei-Gu (GMG) about 40 minutes after the trigger and
obtained the following magnitudes: 
 
Start UT  Exposure Filter  mag   err 
------------------------------------------------- 
14:53:41  10 sec     R    17.51  0.02 
14:56:41  30 sec     B    18.50  0.03   
15:01:22  30 sec     V    18.57  0.02 
15:03:55  20 sec     I    17.68  0.02 
17:26:58  75 sec     R    18.89  0.04 

We continued our observations of GRB 090424 in R band started at 13:42:00 UT on April 
25, 2009. After 20 minutes of exposure time, we obtained the magnitude R=20.59 +/- 
0.07 mag.     
 
All the calibrations were processed by nearby SDSS stars. 
 
The telescope is charged by Yunnan Observatory (YNAO), Chinese Academy of Sciences.   
 
This message might be cited.


 


GRB_name: GRB090429B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9306
SUBJECT: GRB 090429B: Gemini-N further nIR observations
DATE:    09/04/30 11:38:26 GMT
FROM:    Nial Tanvir at IofA U.Cambridge  <nrt@ast.cam.ac.uk>

A. Levan (U. Warwick), A. Cucchiara (PSU), N. Tanvir (U. Leicester),
D. Fox (PSU) & E. Berger (Harvard U.) report:

We re-observed the field of GRB 090429B with NIRI on Gemini-N,
beginning about 30-Apr 08:00 (UT).  The infra-red source reported by
Cucchiara et al. (GCN 9286) is detected, but has faded significantly
to K=20.0 +/- 0.2 mag.  We thus confirm that this source is the
afterglow of the burst.


GRB_name: GRB090427A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9307
SUBJECT: GRB 090427: pseudo-z= 1.48 from prompt emission spectrum
DATE:    09/04/30 14:38:47 GMT
FROM:    Alexandre Pelangeon at LATT,CNRS,U. Toulouse  <alexandre.pelangeon@gmail.com>

A. Pelangeon & J-L. Atteia (LATT-OMP) report:

We used the spectral parameters of GRB 090427
provided by Golenetskii et al. (GCNC 9296)
to compute the spectral pseudo-redshift(**) of this burst
localized by IPN (Pal'shin et al., GCNC 9277).

We find a pseudo-redshift pz= 1.48 +/- 0.20


** cf. http://www.ast.obs-mip.fr/grb/pz


GRB_name: GRB090429A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9308
SUBJECT: GRB 090429A: Swift/UVOT Upper Limits
DATE:    09/04/30 15:15:24 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <Stephen.T.Holland@nasa.gov>

M. M. Chester (PSU), S. T. Holland (CRESST/GSFC/USRA) and
C. B. Markwardt (CRESST/GSFC/UMD) report on the behalf of the Swift
UVOT team:

       The Swift/UVOT observed the field of GRB 090429A starting 49 s
after the BAT trigger (Markwardt, et al., 2009, GCN Circ. 9280).
Settled exposures started at T+67 s.  We do not find any new source,
relative to the DSS, USNO-B1.0, or 2MASS at the position of the XRT
afterglow (Evans, et al. 2009, GCN Circ. 9297).  Preliminary 3-sigma
upper limits for detecting a source in the white finding chart and the
co-added images, using a 2.5 arcsecond radius circular aperture, are

Filter      T_start   T_stop    Exp(s)     Mag
----------------------------------------------
white (fc)       67      217       147   >21.7

v            35,736   58,902       114   >19.8
b            40,727   63,010      1697   >22.1
u            52,833   53,121       284   >21.0
uvw1         50,447   86,297      3336   >22.2
uvm2         44,777   47,341       659   >20.9
uvw2         34,829   57,197      1746   >21.9
white        63,015   63,137       120   >21.5
----------------------------------------------

The quoted upper limits have not been corrected for the expected
Galactic extinction along the line of sight corresponding to a
reddening of E_{B-V} = 0.06 mag (Schlegel, et al., 1998, ApJS, 500,
525).  All photometry is on the UVOT photometry system described in
Poole et al. (2008, MNRAS, 383, 627).


GRB_name: GRB090429B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9309
SUBJECT: GRB 090429B: Swift/UVOT Upper Limits
DATE:    09/04/30 16:03:10 GMT
FROM:    Margaret Chester at PSU  <chester@astro.psu.edu>

M. M. Chester (PSU) and T. N. Ukwatta (GSFC/GWU) report on the behalf
of the Swift/UVOT team:

      The Swift/UVOT observed the field of GRB 090429B starting 78 s
after the BAT trigger (Ukwatta et al. 2009, GCN Circ. 9281). Settled
exposures started at T+99 s.  We do not find any new source at the
position of the XRT afterglow (Beardmore et al. 2009, GCN Circ. 9288).
Preliminary 3-sigma upper limits for detecting a source in the white
finding chart and the co-added images, using a 5 arcsecond radius
circular aperture, are:

Filter      T_start   T_stop    Exp(s)     Mag
----------------------------------------------
white (fc)       99      249    150    >21.0
white           591    10856   1241    >22.2
v               640    12550   1213    >20.6
b               567     6769    381    >20.8
u               311     6621    669    >20.8
uvw1            690     6416    419    >20.5
uvm2            665     6211    439    >21.4
uvw2            616    11762   1339    >20.3
----------------------------------------------

      The quoted upper limits have not been corrected for the expected
Galactic extinction corresponding to a reddening of E_{B-V} = 0.015
in the direction of the XRT position (Schlegel, et al. 1998, ApJS,
500, 525).  All photometry is on the UVOT photometry system described
in Poole et al. (2008, MNRAS, 383, 627).


GRB_name: GRB090429C
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9310
SUBJECT: GRB 090429C: Fermi GBM detection
DATE:    09/04/30 21:44:51 GMT
FROM:    Sheila McBreen at MPE  <smcbreen@mpe.mpg.de>

Sheila McBreen (UCD/MPE) reports on behalf of
the Fermi GBM Team:

"At 12:43:25.70  UT on 29 April 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090429C (trigger 262701807  / 090429530).

The on-ground calculated location, using the GBM trigger
data, is RA = 261.4, DEC = +55.5 (J2000 degrees,
equivalent to 17 h 26 m, +55 d 30 '), with an uncertainty
of 4.9 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 112 degrees.

The GBM light curve consists of two pulses
with a duration of about 13 s (8-1000 keV).
The time-averaged spectrum from T0-2 s to T0+11 s is
adequately fit by a simple power law function
with index -1.43 +/- 0.04 (chi squared 513 for 471 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(3.7 +/- 0.1)E-6 erg/cm^2. The 0.256 sec peak photon flux measured
starting from T0+0.768 s in the 8-1000 keV band
is 6.7 +/- 0.4 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090429D
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9311
SUBJECT: GRB 090429D: Fermi GBM detection
DATE:    09/04/30 22:09:24 GMT
FROM:    Narayana Bhat at U Alabama/Huntsville/GBM  <Narayana.Bhat@nasa.gov>

P. N. Bhat (UAH) reports on behalf of the Fermi GBM Team:

"At 18:03:57.51 UT on 29 April 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090429D (trigger 262721039 / 090429753).

The on-ground calculated location, using the GBM trigger
data, is RA = 125.2, DEC = 6.2 (J2000 degrees,
equivalent to 08 h 20.8 m, 06 d 12'), with an uncertainty
of 4.6 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 33 degrees.

[This burst was also independently detected by Konus Wind. Swift BAT
confirms this GRB which occurred while it was slewing.]


The GBM light curve consists of 3 short pulses (two which occurred before
the trigger) with a duration (T90) of about 11 s (8-1000 keV).
The time-averaged spectrum from T0-13.248 s to T0+1.088 s is
adequately fit by a power law function with an exponential
high energy cutoff.  The power law index is -0.87 +/- 0.27 and
the cutoff energy, parametrized as Epeak, is 223 +/- 72.5 keV
(chi squared 459 for 487 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(1.6 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0 s in the 8-1000 keV band
is 0.86 +/- 0.16 ph/s/cm^2.

[A Band function fits the spectrum equally well (chi squared 456 for 486
d.o.f.) with Epeak= 152.8 +/- 92.4 keV, alpha = -0.66 +/- 0.53 and beta =
-1.88+/- 0.32.] 

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090426A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9312
SUBJECT: GRB 090426: optical observations
DATE:    09/04/30 23:36:12 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

V. Rumyantsev, K. Antoniuk (CrAO), A. Pozanenko (IKI) report on behalf of 
larger GRB follow-up collaboration:

We observed the afterglow (Cummings et al. GCN 9254, Xin et al., GCN  9255) 
of  the Swift GRB 090426 (Swift trigger 350479, Cummings et al. GCN 9254) in 
R and B filters on Apr. 26  between (UT) 18:03:06 -- 19:47:38 with AZT-11 
telescope of CrAO.  We  detect the afterglow in  stacked image in R. 
Astrometry of the afterglow is RA(J2000):  12 36 18.10 Dec(J2000): +32 59 
08.77  with uncertainty of 0.5 arcsec is  compatible with reported in GCN 
9265 (Oates et al).

Preliminary photometry of combined images is based on  USNO-B1.0 
1230-0248707  star  RA=12:36:18.03 Dec=+33:00:02.2   is  following:

T0+     Filter, Exposure, mag.,     err.
(d)             (s)

0.2342  R 15x180   21.3 +/-0.2


The combined image can de found at
http://grb.rssi.ru/GRB090426/GRB090426_AZT-11_R.gif

Taking together early observations (Yoshida et al, GCN 9266, Kinugasa et al, 
GCN 9292, Mao et al, GCN 9285) with our photometry we estimate power law 
decay index as ~0.9 which is compatible with decay index estimated by 
Olivares et al (GCN 9268). 


GRB_name: GRB090424A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9313
SUBJECT: GRB 090424, SMARTS optical/IR afterglow monitoring
DATE:    09/05/01 03:00:53 GMT
FROM:    Bethany Cobb at UC Berkeley  <bcobb@astro.berkeley.edu>

B. E. Cobb (UC Berkeley) reports:

Using the ANDICAM instrument on the 1.3m telescope at CTIO, we obtained
optical/IR imaging of the error region of GRB 090424 (GCN 9223, Cannizzo
et al.) over nine epochs between ~0.5 and 5.6 days post burst.  In our
first epoch of imaging, total summed exposure times amounted to
15 minutes in I and V and 12 minutes in J and K.  All later epochs had
total summed exposure times of 36 minutes in I and 30 minutes in J.

The optical afterglow of GRB 090424 (e.g. GCN 9223, Cannizzo
et al. & GCN 9224, Yuan et al.) is observed to fade steadily in our
imaging with no indication of a jet break between ~0.5 and 5.6 days 
post-burst.  The combined light of the afterglow and the underlying galaxy
fades with a decay rate of alpha = -0.72 (where afterglow flux is 
proportional to t^alpha).  Assuming that the galaxy has an intrinsic 
magnitude of I=21.6 (based on the SDSS i and r values and the Lupton 2005 
transformation equations), then the afterglow's true decay rate is
alpha = -1.2 over these epochs.

The afterglow + host galaxy photometry is measured as follows (no
correction has been made for Galactic extinction):

mid-exposure
time (days
post-burst) I mag       J mag          V mag         K mag
-------------------------------------------------------------------
0.45031     19.42+/-0.04  18.31+/-0.06  20.61+/-0.04  16.38+/-0.05
0.50291     19.45+/-0.04  18.11+/-0.04  ...           ...
0.57498     19.61+/-0.04  18.22+/-0.05  ...           ...
0.62815     19.70+/-0.04  18.23+/-0.05  ...           ...
1.53459     20.45+/-0.05  19.18+/-0.08  ...           ...
2.49012     20.92+/-0.05  19.61+/-0.11  ...           ...
3.51877     20.99+/-0.05  19.53+/-0.09  ...           ...
4.56909     21.24+/-0.08   > 19.7       ...           ...
5.56135     21.31+/-0.10   > 19.7       ...           ...

(Optical photometry is calibrated against Landolt standard stars
and IR photometry is calibrated against 2MASS stars in the field.)


GRB_name: GRB090428B
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9314
SUBJECT: GRB 090428B: Suzaku WAM observation of the prompt emission
DATE:    09/05/01 05:22:26 GMT
FROM:    Takeshi Uehara at Hiroshima U  <uehara@hirax7.hepl.hiroshima-u.ac.jp>

T. Uehara, Y. Hanabata, T. Takahashi, Y. Fukazawa(Hiroshima U.),
M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA),
K. Kono, E. Sonoda, M. Yamauchi, N. Ohmori, H. Hayashi,
K. Noda, A. Daikyuji, Y. Nishioka (Univ. of Miyazaki),
W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda,
T. Sugasahara (Saitama U.), Y. Urata (NCU),
T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo),
K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y. E. Nakagawa,
T. Tamagawa (RIKEN), S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.),
on behalf of the Suzaku WAM team, report:

The long GRB 090428B (Fermi/GBM
trigger 262617313 / 090428552, Bissaldi et al., GCN 9295)
triggered the Suzaku Wide-band  All-sky Monitor (WAM) which covers an
energy range of 50 keV - 5 MeV at 13:15:12.66 UT (=T0).
The observed light curve shows a single FRED-like peak
starting at T0-10s, ending at T0+9s, with a duration (T90) of about 19.0 seconds. 

The fluence in 100 - 1000 keV was 2.6(+0.5/-0.9) X10^-6 erg/cm^2.
The 1-s peak flux measured from T0+1s was 1.1 photons/cm^2/s in the same
energy range.

Preliminary result shows that the time-averaged spectrum from T0-10s to
T0+9s is well fitted by a single power-law with a photon index
of 2.0 (+0.5/-0.4) (chi^2/d.o.f = 5/7).
All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.

The light curves for this burst are available at:

 http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html


GRB_name: GRB090424A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9316
SUBJECT: ICSP VLF observation of GRB090424 from four receivers
DATE:    09/05/01 13:25:00 GMT
FROM:    Sandip K. Chakrabarti at S.N. Bose Nat. Centre for Basic Sci.  <chakraba@bose.res.in>

ICSP VLF observation of GRB090424 from four receivers

Sandip K. Chakrabarti (S. N. Bose Centre and ICSP), Sushanta K. Mondal (ICSP),
Asit Choudhury (ICSP, Malda branch), Achintya Chatterjee (ICSP, Malda Branch),
Narendra N. Patra (Univ. Pune) and D. Bhowmick (ICSP)

Three ICSP VLF receivers clearly observed the effects of GRB090424
(GCN#s 9223, 9230) on the ionosphere simultaneously. The subflare point
(16.8d N , 123.76d E) being closer to eastern India the signal was prominent.
Two receivers were kept at Kolkata (22.5N, 88.5d E)  at sixteen kilometers 
(~ 10 miles) apart, while a third receiver was kept at Malda (25d N, 88d E)
which is about 200 miles away. All the three receivers detected the GRB right
after triggering and the correlation of the signals were found excellent for
about ~100 seconds. Before the triggering, the correlation was poor. The signal
from a fourth ICSP receiver at Pune (~1000 miles from Kolkata) in western 
India (18.5d N, 74d N) was very poor.

A comparison of the smoothed signals can be found in allthree.jpg in
http://www.bose.res.in/~chakraba/grb090424-1.html. This message may be cited.


GRB_name: GRB090427A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9317
SUBJECT: ICSP VLF observation of GRB090427 from two receivers
DATE:    09/05/01 13:43:55 GMT
FROM:    Sandip K. Chakrabarti at S.N. Bose Nat. Centre for Basic Sci.  <chakraba@bose.res.in>

ICSP VLF observation of GRB090427 from two receivers

Sushanta K. Mondal (ICSP), Sandip K. Chakrabarti (S. N. Bose Centre and ICSP),
Narendra N. Patra (Univ. Pune) and D. Bhowmick (ICSP)

Two ICSP VLF receivers clearly observed the effects of GRB090427
(GCN#s 9277, 9296) on the ionosphere simultaneously. The subflare point
(13.5d S, 28.2d E) being closer to western India the signal was prominent
from our Pune receiver (18.5d N, 74d N) while it was weaker at our
Kolkata (22.5N, 88.5d E) receiver in eastern India. These two stations were
~1000 miles apart.

Both the receivers detected the GRB right after triggering and the
correlation of the signals were found excellent for about ~70 seconds.
Before the triggering, the correlation was poor.

A comparison of the smoothed signals can be found in grb27GCN.jpg in
http://www.bose.res.in/~chakraba/grb090427-1.html. This message may be cited.


GRB_name: GRB090429A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9318
SUBJECT: GRB 090429A: ROVOR magnitude limit
DATE:    09/05/01 15:46:47 GMT
FROM:    J. Ward Moody at BYU  <rovor.byu@gmail.com>

Richard L. Pearson and J. Ward Moody report for Brigham Young
Univerisitys ROVOR team:

We observed the field around GRB 090429A (Swift trigger 350853,
Markwardt et al., GCN 9280) with the ROVOR (Robotic Observatory for
Variable Object Research) 16 telescope from Delta, Utah. Beginning 30
April 2009 at 03:46:50 UT (22.3 hours after outburst), observations
were obtained for a complete integration time of 50 minutes in white
light. No detection was made after stacking the images. Using the
magnitude limits established by Olivares et al., GCN Circ. 9303 on the
2.2m ESO/MPI telescope at La Silla Observatory, we estimate a
magnitude limit of 22  1 mag on these observations.


GRB_name: GRB090427A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9319
SUBJECT: GRB 090427: GROND observations
DATE:    09/05/04 00:07:14 GMT
FROM:    Felipe Olivares Estay at MPE  <felipe@mpe.mpg.de>

F. Olivares, T. Kruehler, J. Greiner (all MPE Garching) report on behalf of
the GROND team: 

We observed the central area of the error box of GRB 090427 localized by the
IPN (Pal'shin et al., GCN #9277) simultaneously in g'r'i'z'JHK with GROND
mounted at the 2.2m ESO/MPI telescope at La Silla Observatory (Chile).
Three adjacent pointings centered at 

RA = 15,43,31.0  Decl. = -13,40,00
RA = 15,43,43.4  Decl. = -13,30,00 (center of IPN box)
RA = 15,43,55.0  Decl. = -13,20,00 

have been observed with our 10x10 arcmin (in JHK) and 5.4x5.4 arcmin
(g'r'i'z') field-of-view, thus covering about 27% and 8% of the full error
box respectively (see sketch at http://www.mpe.mpg.de/~jcg/grb090427.html). 

Observations started on 29 Apr. 2009 at 06:20 UT, 30.9 h after the burst,
and consisted, for each of the three fields, of a set of images with a
total integration time of 8 min in JHK and 7.7 min in g'r'i'z'. A second
epoch of all three fields was obtained on 30 Apr. 2009 starting at 05:18 UT. 

Image subtraction of the two epochs does not reveal a variable source
in any of the three fields, down to limiting magnitudes (all in AB system) 
of 

g' > 23.9
r' > 23.8
i' > 23.5
z' > 23.2
J > 22.2
H > 21.7
K > 20.6 

These magnitudes have been obtained using 2MASS field stars and the GROND
zeropoints as reference.


GRB_name: GRB090424A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9320
SUBJECT: GRB 090424: optical observations
DATE:    09/05/04 00:21:25 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

V. Rumyantsev, K. Antoniuk (CrAO), A. Pozanenko (IKI) report on behalf of 
larger GRB follow-up collaboration:

We observed the afterglow (Cannizzo et al. GCN 9223; Yuan GCN 9224) of  the 
Swift GRB 090424  (Trigger 350311; Cannizzo et al., GCN 9223) in R filter on 
Apr. 24   (18:25:36 -- 19:23:38) and  Apr. 26 (19:57:14 -- 21:01:01) with 
AZT-11 telescope of CrAO.  We  detect the afterglow in  combined images of 
both epochs. Astrometry of the afterglow is RA(J2000):  12 38 05.1 
Dec(J2000): +16 50 14.72   with uncertainty of 0.5 arcsec.
Preliminary photometry of combined images is based on  USNO-B1.0 
1068-0228255  star  RA=12:38:02.33  Dec=+16:51:10.0  is  following:

T0+     Filter, Exposure, mag.,     err.
(d)             (s)

0.1972 R 20x180 19.27  +/-0.06
2.2628 R 20x180 21.0   +/-0.2

The photometry is contaminated with possible host galaxy (Evans et al. GCN 
9226).

The combined image of the Apr. 24 observation can de found at
http://grb.rssi.ru/GRB090424/GRB090424_AZT-11_R.gif 


GRB_name: GRB080913A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9321
SUBJECT: GRB 080913: 250 GHz upper limit for a z=6.7 GRB with MAMBO-2 at the IRAM 30m
DATE:    09/05/04 18:16:48 GMT
FROM:    Dominik A. Riechers at Caltech  <dr@caltech.edu>

D. A. Riechers (Caltech), F. Walter (MPIA Heidelberg), F. Bertoldi
(AIfA Bonn), C. L. Carilli (NRAO), P. Cox (IRAM) report:

"We used the Max-Planck-Millimeter Bolometer (MAMBO-2) array at the
IRAM 30-m telescope to observe the field of view toward the host
galaxy of GRB 080913 (GCN 8217) at redshift z=6.7 (GCN 8225), RA
04:22:54.74, Dec -25:07:46.2 (J2000) at 250 GHz. Observations were
carried out for 3.7 hr between 2008 November 13 and 15.  We obtained a
non-detection of

    S_nu(250 GHz,1.20 mm) = 0.34 +/- 0.45 mJy

(1 sigma error), i.e. a 3 sigma upper flux density limit of 1.35 mJy
on the dust continuum in the GRB host galaxy at 1.2 mm (rest-frame 156
um). The 117-element MAMBO-2 bolometer detectors cover 210-290 GHz
(half power). The bolometers have a FWHM beam size of 10.7 arcsec, at
a pixel spacing of 20 arcsec. Observations were carried out in ON-OFF
observing mode under good weather conditions. Calibrations were
performed on J0348-278 and J0609-157.

We acknowledge the excellent support of the staff at IRAM. IRAM is
supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain). This
message may be cited."


GRB_name: GRB090423A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9322
SUBJECT: GRB 090423: 250 GHz upper limit for a z=8.2 GRB with MAMBO-2 at the IRAM 30m
DATE:    09/05/04 18:21:20 GMT
FROM:    Dominik A. Riechers at Caltech  <dr@caltech.edu>

D. A. Riechers (Caltech), F. Walter (MPIA Heidelberg), F. Bertoldi
(AIfA Bonn), C. L. Carilli (NRAO), P. Cox (IRAM), C. Kramer (IRAM),
D. Riquelme (IRAM) report:

"We used the Max-Planck-Millimeter Bolometer (MAMBO-2) array at the
IRAM 30-m telescope to observe the field of view toward the host
galaxy of GRB 090423 (GCN 9198) at redshift z=8.2 (GCN 9219), RA
09:55:33.19, Dec +18:08:57.7 (J2000) at 250 GHz. Observations were
carried out for 4.5 hr on 2009 April 25, centered at UT 18.5.  We
obtained a non-detection of

    S_nu(250 GHz,1.20 mm) = 0.23 +/- 0.32 mJy

(1 sigma error), i.e. a 3 sigma upper flux density limit of 0.96 mJy
on the GRB afterglow and the dust continuum in the host galaxy at 1.2
mm (rest-frame 130 um). Together with the 3 mm observations carried
out at the Plateau de Bure Interferometer (GCN 9273), this indicates a
flat spectral slope at millimeter wavelengths. The 117-element MAMBO-2
bolometer detectors cover 210-290 GHz (half power). The bolometers
have a FWHM beam size of 10.7 arcsec, at a pixel spacing of 20
arcsec. Observations were carried out in ON-OFF observing mode under
good weather conditions, with low sky noise and opactities of
tau=0.1-0.26 (derived from skydips). Calibrations were performed on
CW-LEO.

We acknowledge the excellent support of the staff at IRAM. IRAM is
supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain). This
message may be cited."


GRB_name: GRB090423A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9323
SUBJECT: GRB 090423: optical limit
DATE:    09/05/05 00:21:38 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

V. Rumyantsev, E. Pavlenko, O. Antoniuk (CrAO), A. Pozanenko (IKI) report on 
behalf of  larger GRB follow-up collaboration:

We observed the error box of  Swift GRB 090423 (Krimm et al. GCN 9198)  on 
Apr. 23 between (UT)  090423 23:34:46 -- 090424 01:13:20 in R -filter with 
Shajn telescope of CrAO.  The observation was planning and performed before 
the redshift z ~ 8 of GRB 090423 was confirmed  (Cucchiara et al. GCN 9213; 
Olivares et al. GCN  9215; Thoene  et al.  GCN 9216; Tanvir et al.  GCN 
9219). Indeed we do not detect optical afterglow at the place of IR 
afterglow detection (Tanvir et al.  GCN 9202; Levan et al.  GCN 9206; 
Cucchiara  et al.  GCN  9209).  Limiting magnitude of the combined image is 
following :

T0+     Filter, Exposure, mag.,     err.
(d)                  (s)

0.6877  R       93x60    >24.0 (3 sigma)

The combined R-image  can be found at 
http://grb.rssi.ru/GRB090423/GRB090423_ZTSh_a.gif 


GRB_name: GRB090323A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9324
SUBJECT: GRB 090323: optical observations
DATE:    09/05/05 00:46:36 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

V. Rumyantsev (CrAO), A. Pozanenko (IKI) report on behalf of  larger GRB 
follow-up collaboration:

We observed the afterglow (Updike et al., GCN 9026; Cenko et al., GCN 9027) 
of Fermi GRB 090323 (GBM trigger 259459364 / 090323002; Ohno et al., GCN 
9021)  on Apr. 28 and Apr. 29 with Shajn telescope of CrAO.  We  clearly 
detect the afterglow in R and do not detect in I- filter. Astrometry of the 
afterglow is RA(J2000):  12 42 50.29 Dec(J2000): +17 03 11.98 with 
uncertainty of 0.2 arcsec is compatible with reported in GCN 9026.

A photometry of combined images based on  USNO-B1.0  star  RA=12:42:39.3 
Dec=+17:05:05.7  (previously used by Kann et al. GCN 9033)   is following:

T0+     Filter, Exposure, mag.,  err.  Seeing
(d)             (s)

5.9934 R  91x60  22.7 +/- 0.1        1.6"
6.8990 I  84x60  >22.4  (3sigma)   2.9"

The combined image of the observation on Apr. 28 can be found at 
http://grb.rssi.ru/GRB090323/GRB090323_R_ZTSh_090328.gif

Our photometry in R is compatible with estimations obtained in nearby epochs 
(Kann et al. GCN 9041, de Ugarte Postigo et al. GCN 9051) and confirms the 
flattening of the light curve mentioned by de Ugarte Postigo et al. (GCN 
9051).  The non-detection of the afterglow in I-filter in  second epoch of 
our  observation  (T0+6.899 d) tentatively supports the steepening of light 
curve discussed by Kann et al. (GCN 9063). Indeed the upper limit I > 22.4 
is translating into R > 22.8 provided the color index R-I ~ 0.4 obtained 
from observations of Updike et al. (GCN 9026) and  Guidorzi et al. (GCN 
9039) is not changing along  late time light curve. 


GRB_name: GRB090509A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9325
SUBJECT: GRB 090509: Swift detection of a burst
DATE:    09/05/09 05:21:22 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

D. Grupe (PSU), S. D. Barthelmy (GSFC), M. M. Chester (PSU),
H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC),
D. M. Palmer (LANL), J. L. Racusin (PSU) and M. H. Siegel (PSU)
report on behalf of the Swift Team:

At 05:10:03 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090509 (trigger=351525).  Swift did not slew to this burst. 
The BAT on-board calculated location is 
RA, Dec 241.404, -28.404 which is 
   RA(J2000)  =  16h 05m 37s
   Dec(J2000) = -28d 24' 12"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows multiple peaks
with a duration of about 30 sec.  The peak count rate
was ~1300 counts/sec (15-350 keV), at ~20 sec after the trigger. 

Due to the Moon observing constraint, Swift cannot slew to the 
BAT position until May 12.  There will thus be no XRT or UVOT data 
for this trigger. 

Burst Advocate for this burst is D. Grupe (grupe AT astro.psu.edu). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090509A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9326
SUBJECT: GRB 090509: GROND afterglow candidate
DATE:    09/05/09 06:00:25 GMT
FROM:    Thomas Kruehler at MPE/MPI  <kruehler@mpe.mpg.de>

F. Olivares, J. Greiner, T. Kruehler (all MPE Garching) and S. Klose (TLS) 
report on behalf of the GROND team:

We observed the field of GRB 090509 (Swift trigger 351525; Grupe et
al., GCN #9325) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2 m ESO/MPI telescope at La Silla
Observatory (Chile).

We detect a bright uncatalogued source in all bands at

16:05:39.01 -28:23:59.7

with a magnitude of r' = 17.9 at 15 min after the burst, calibrated using 
the GROND zeropoint.


GRB_name: GRB090509A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9327
SUBJECT: GRB 090509: REM NIR afterglow
DATE:    09/05/09 06:03:38 GMT
FROM:    Stefano Covino at Brera Astronomical Observatory  <stefano.covino@gmail.com>

S. Covino, P. D'Avanzo, L.A. Antonelli, D. Fugazza, L.   
Calzoletti,  S. Campana, G. Chincarini, M.L. Conciatore, S. Cutini,   
V. D'Elia,  F. D'Alessio, F. Fiore, P. Goldoni, D. Guetta, C.  
Guidorzi, G.L. Israel, E. Maiorano, N. Masetti, A. Melandri, E.J.A.  
Meurs, L. Nicastro, E. Palazzi, E. Pian, S. Piranomonte, L. Stella,   
G. Stratta, G. Tagliaferri, G. Tosti, V. Testa, S.D. Vergani, F.   
Vitali report on behalf of the REM team:

The robotic 60-cm REM telescope located at La Silla (Chile) observed  
automatically the field of the GRB 090509 (Grupe et al. GCN9325)  
starting about 3min after the burst.  We detect  a fading object in  
the BAT error circle in our first H-band images at H~14.3 at  
coordinates: RA(J2000) 16:05:38.99; Dec(J2000) -28:23:58.7 with 1  
arcsec error. Moon is only at about 15 deg preventing useful optical  
observations.

[GCN OPS NOTE(09may09): Per author's request, the "R~14.3" was changed
to "H~14.3".]
[GCN OPS NOTE(09may09): Per self request, D.Malesani was removed
from the author list.]


GRB_name: GRB090509A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9328
SUBJECT: GRB 090509: GROND further analysis and redshift limit
DATE:    09/05/09 12:31:34 GMT
FROM:    Thomas Kruehler at MPE/MPI  <kruehler@mpe.mpg.de>

F. Olivares, T. Kruehler (MPE Garching), S. Klose (Tautenburg), and J. 
Greiner (MPE Garching) report on behalf of the GROND team:

In addition to our previous GCN (Olivares et al., GCN #9326) we report here 
the observed preliminary magnitudes (in the AB system) for the afterglow 
(GCN #9326 and Covino et al., GCN #9327) of GRB 090509 (Grupe et al., GCN 
#9325). Based on 8 min of effective exposure starting at 5:22 UT (12 
minutes after the trigger), we measure

g = 18.12 +/- 0.01
r = 17.75 +/- 0.01
i = 17.48 +/- 0.01
z = 17.22 +/- 0.01
J = 16.87 +/- 0.07
H = 16.57 +/- 0.12
K = 16.31 +/- 0.17

The quoted error is statistical only. There is an additional systematic 
error from the calibration against the GROND zeropoints and 2MASS field 
stars which is expected to be in the 0.1 mag range.

After correcting for a Galactic foreground extinction corresponding to a 
reddening of E_(B-V)=0.206 mag (Schlegel et al.), the g' to K band is well 
described with a single power law. This implies, that Lyman alpha is below 
or very close to the blue edge of the g' band, and constrains the redshift 
to smaller than z < 3.0 (90% confidence limit).


GRB_name: GRB090418A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9329
SUBJECT: GRB 090418A: optical observation
DATE:    09/05/09 20:15:43 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

V. Rumyantsev, E. Pavlenko(CrAO), A. Pozanenko (IKI)  report on behalf of 
larger GRB follow-up collaboration:

We observed the afterglow of  the Swift GRB 090418A (Mangano et al., GCN 
9149) in I-filter on Apr. 20 (UT) 02:34:12 - 04:08:27
and in R-filter on Apr. 20 (UT) 21:03:05 - 22:49:20 with Shajn telescope of 
CrAO. We clearly detect afterglow in both epochs in stacked images. 
Preliminary photometry  of Apr. 20 as well a photometry in V-filter of  Apr. 
18 observations (Pavlenko et al. GCN 9179) is following:

T0+     Filter, Exposure, mag.,     err.  UL Seeing
(d)             (s)

0.5476  V       17x60     22.3 +/- 0.2  23.2  1.9"
2.4507  R       70x60     22.8 +/- 0.1  24.4  1.9"

Due to worse seeing (2.4") on Apr. 20 (UT) 02:34:12 - 04:08:27 the afterglow 
is evidently contaminated with nearby galaxy and photometry will be reported 
later. The photometry of Apr. 20 (UT) 21:03:05 - 22:49:20  also should be 
treated with caution due to possible contamination. 


GRB_name: GRB090408A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9330
SUBJECT: GRB 090408: optical upper limit
DATE:    09/05/09 20:55:42 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

D. Shakhovskoy, V. Rumyantsev (CrAO), A. Pozanenko (IKI) report on behalf of 
larger GRB follow-up collaboration:

We observed  the Swift GRB 090408  (Swift trigger=348720; Stroh  et al., GCN 
9110) in R-filter   on Apr. 8  with AZT-11 telescope of CrAO.  We do not 
detect any new object within BAT erorr box (Stroh  et al., GCN 9110)  in  a 
stacked image in R at ~ 3.7 hrs after burst onset.  An upper limit 
photometry of combined images  based on USNO B1.0 1275-0286482 
RA(J2000)=15:26:27.78 Dec(J2000)= +37:33:46.2 R =17.55 is  following:

T0+     Filter, Exposure, mag.,     err.
(d)             (s)

0.1561  R   20x180     > 20.4 (3sigma)


GRB_name: GRB090510A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9331
SUBJECT: GRB 090510: Swift detection of a short hard burst
DATE:    09/05/10 00:41:41 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

E. A. Hoversten (PSU), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),
M. M. Chester (PSU), D. Grupe (PSU), J. A. Kennea (PSU),
H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (MSSL),
D. M. Palmer (LANL) and T. N. Ukwatta (GSFC/GWU) report on behalf of
the Swift Team:

At 00:23:00 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090510 (trigger=351588).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 333.555, -26.606 which is 
   RA(J2000) = 22h 14m 13s
   Dec(J2000) = -26d 36' 19"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a single spike 
with a duration of about 0.5 sec.  The peak count rate
was ~21000 counts/sec (15-350 keV), at 0 sec after the trigger. 

The XRT began observing the field at 00:24:34.6 UT, 94.1 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 333.55195, -26.58345 which is
equivalent to:
   RA(J2000)  = 22h 14m 12.47s
   Dec(J2000) = -26d 35' 00.4"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 81 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of
1.66e+20 cm^-2 (Kalberla et al. 2005). 

UVOT took a finding chart exposure of 150 seconds with the White 
filter  starting 97 seconds after the BAT trigger. No credible 
afterglow candidate has  been found in the initial data products. 
The 2.7'x2.7' sub-image  does not include the position  of the XRT
candidate. The 8'x8' region for the list of sources   generated
on-board covers the XRT position and 100% of the BAT error  circle. 
The list of sources is  typically complete to about 18 mag.  No
correction has been made for the  expected extinction  corresponding
to E(B-V) of 0.02. 

We note the existence of the galaxy 2dFGRS TGS176Z296 at
a distance of 140 arcsec from the XRT position. 

Burst Advocate for this burst is E. A. Hoversten (hoversten AT astro.psu.edu). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090510A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9332
SUBJECT: GRB 090510: Swift/UVOT Detection of a Candidate Optical Afterglow
DATE:    09/05/10 01:26:57 GMT
FROM:    Frank Marshall at GSFC  <marshall@milkyway.gsfc.nasa.gov>

F. E. Marshall (GSFC) and E. A. Hoversten (PSU) report on behalf of the
Swift team:

UVOT took a second finding chart exposure of 250 seconds with the U filter starting
309 seconds after the BAT trigger for GRB 090510 (Hoversten et al.
GCN Circ. 9331). There is a candidate afterglow in the
rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 22:14:12.54 = 333.55227
  DEC(J2000) = -26:34:58.4  = -26.58290
with a 90%-confidence error radius of about 0.69 arc sec. This position is 0.7
arc sec. from the center of the XRT error circle. The estimated magnitude is
18.95 with a 1-sigma error of about 0.17. No information about
variability is available at this time. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.02. 


GRB_name: GRB090509A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9333
SUBJECT: GRB 090509, SMARTS optical/IR afterglow observations
DATE:    09/05/10 02:05:34 GMT
FROM:    Bethany Cobb at UC Berkeley  <bcobb@astro.berkeley.edu>

B. E. Cobb (UC Berkeley) reports:

Using the ANDICAM instrument on the 1.3m telescope at CTIO, we
obtained optical/IR imaging of the error region of GRB 090509
(Grupe et al. GCN 9325) beginning approximately 0.8 hours post-burst
(2009-05-09 05:59 UT).  Several dithered images
were obtained in each filter, with total summed exposure times
of 180s in each of BRIJK and 120s in each of H and V.

The GRB afterglow (Olivares et al. GCN 9326, Covino et al. GCN 9327)
is detected in all filters with the following magnitudes
at a mid-exposure time of 2009-05-09 06:14 UT (1.07 hours
post-burst):

B= 20.18 +/- 0.13
V= 19.68 +/- 0.16
R= 19.02 +/- 0.10
I= 18.76 +/- 0.09
J= 17.70 +/- 0.16
H= 17.07 +/- 0.15
K= 16.48 +/- 0.22

(Optical photometry is calibrated against Landolt standard stars
 and IR photometry is calibrated against 2MASS stars in the field.)


GRB_name: GRB090510A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9334
SUBJECT: Fermi LAT detection of GRB 090510
DATE:    09/05/10 04:26:20 GMT
FROM:    Masanori Ohno at ISAS/JAXA  <ohno@astro.isas.jaxa.jp>

Masanori Ohno(ISAS/JAXA), Veronique Pelassa(CNRS/IN2P3/LPTA) report
on behalf of the Fermi LAT team:

At 00:23:01.22 UT on 10 May 2009, the Fermi Large Area Telescope (LAT) triggered and located GRB 090510 (trigger 263607783 / 090510016).
Emission was observed in the LAT up to GeV energy band with a detection significance of more than 5 sigma.

The best LAT on-board localization is found to be
(RA,Dec=333.400, -26.767) with an error radius of 7 arcmin (statistical only).
This position is consistent with both Fermi/GBM and Swift/XRT position.

Further analysis is ongoing.
We suggest follow up observation for this burst.

The points of contact for this burst is

 Masanori Ohno ohno@astro.isas.jaxa.jp

The Fermi LAT is a pair conversion telescope designed to
cover the energy band from 20 MeV to greater than 300 GeV.
It is the product of an international collaboration between NASA and DOE in the U.S.
and many scientific institutions across France, Italy, Japan and Sweden.

This message can be cited. 


GRB_name: GRB090509A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9335
SUBJECT: GRB 090509: Swift-BAT refined analysis
DATE:    09/05/10 05:41:38 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

J. Tueller (GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
D. Grupe (PSU), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD),
D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090509 (trigger #351525)
(Grupe, et al., GCN Circ. 9325).  The BAT ground-calculated position is
RA, Dec = 241.426, -28.420 deg, which is 
   RA(J2000)  =  16h 05m 42.3s 
   Dec(J2000) = -28d 25' 12.6" 
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 29%.
 
The mask-weighted light curve shows multiple overlapping peaks starting
at ~T-4 sec, peaking at ~T+21 sec, and ending at ~T=3 sec.
T90 (15-350 keV) is 20.4 +- 1.7 sec (estimated error including systematics).
 
The time-averaged spectrum from T-1.1 to T+22.4 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.54 +- 0.16.  The fluence in the 15-150 keV band is 1.1 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+20.73 sec in the 15-150 keV band
is 1.5 +- 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/351525/BA/


GRB_name: GRB090510A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9336
SUBJECT: GRB 090510: Fermi GBM detection
DATE:    09/05/10 05:46:27 GMT
FROM:    Sylvain Guiriec at UAH  <sylvain.guiriec@lpta.in2p3.fr>

S. Guiriec, V. Connaughton and M. Briggs (UAH)
report on behalf of the Fermi GBM Team:

"At 00:22:59.97 UT on 2009 May 10, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090510 (trigger 263607781 / 090510016) which
was also detected by the Swift-BAT (Hoversten et al. 2009, GCN 9331) and
the Fermi-LAT (Ohno et al. 2009, GCN 9334).

The GBM position is consistent with those reported by Swift and the LAT.

The GBM triggered on a precursor lasting 30 ms followed 0.4 s later by an
intense and hard emission period of 0.5 s and a tail lasting
a further 0.5 s.  The intense period has several narrow peaks and
its integrated spectrum is well fit by a Band function with
alpha = -0.80 +/- 0.03, beta = 2.6 +/- 0.3 and EPeak = 4.4 +/- 0.4 MeV.

The peak flux on a 64 ms timescale between 8 keV and 40 MeV was
measured 0.55 s after the trigger to be 80 ph.cm^-2.s^-1.
The 8 keV to 40 MeV fluence in the 0.512 s long period of intense emission
is  (3.0  0.2) E-5 erg.cm^-2.

The spectral analysis results presented above are preliminary;
further analysis is on-going."


GRB_name: GRB090510A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9337
SUBJECT: GRB 090510: Swift-BAT refined analysis
DATE:    09/05/10 06:08:40 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

T. N. Ukwatta (GWU) S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
E. A. Hoversten (PSU), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD),
D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC)
(i.e. the Swift-BAT team):
 
Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090510 (trigger #351588)
(Hoversten, et al., GCN Circ. 9331).  The BAT ground-calculated position is
RA, Dec = 333.552, -26.598 deg, which is 
   RA(J2000)  =  22h 14m 12.6s 
   Dec(J2000) = -26d 35' 51.1" 
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 16%.
 
The mask-weighted light curve shows a small precursor peak at ~T-0.54 sec
(width ~ 30 msec).  Then the main peak starts at ~T-0.05 sec, peaks at T+0.04 sec
with a width of ~50 msec.  Then come two smaller peaks at T+0.24 and T+0.32 sec,
each about 40 msec in width.  At the 3-sigma level, there is the possibility
of low-level emission between T+110 sec to ~T+170 sec.  T90 (15-350 keV)
is 0.3 +- 0.1 sec (estimated error including systematics).
 
The time-averaged spectrum from T+0.0 to T+0.4 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
0.98 +- 0.20.  The fluence in the 15-150 keV band is 3.4 +- 0.4 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.30 sec in the 15-150 keV band
is 9.7 +- 1.1 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/351588/BA/


GRB_name: GRB090510A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9338
SUBJECT: GRB 090510: NOT afterglow confirmation
DATE:    09/05/10 10:30:19 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@astro.ku.dk>

G. Olofsson, M. Ergon (Univ. Stockholm), D. Malesani, J.P.U. Fynbo 
(DARK/NBI), P. Jakobsson (Univ. Iceland), N.R. Tanvir, K. Wiersema 
(Univ. Leicester), A.J. Levan (Univ. Warwick), report on behalf of a 
larger collaboration:

We observed the field of short Swift/Fermi GRB 090510 (Hoversten et al., 
GCN 9331; Ohno & Pelassa, GCN 9334; Guiriec et al., GCN 9336) with the 
Nordic Optical Telescope equipped with ALFOSC. Observations were carried 
out in twilight and at high airmass (~3).

The candidate afterglow (Marshall & Hoversten, GCN 9332) is clearly 
detected in a stack of our images taken at a mean epoch May 10.215 UT 
(4.7 hr after the GRB). Calibrating against closeby USNO stars (R1 
magnitudes), we get R ~ 21.2. Comparing this value with the magnitude 
reported by Marshall & Hoversten (GCN 9332) indicates fading, thus 
confirming that this object is the afterglow of GRB 090510.

Astrometry of the field yields the following coordinates for the 
afterglow (0.4" error):

RA(J2000) = 22:14:12.64
Dec(J2000) = -26:35:02.8

which is consistent with the UVOT position. We note the presence of a 
fainter source ~1" East of the afterglow. A finding chart is posted at 
the following URL:

http://www.astro.ku.dk/~malesani/GRB/090510/090510_finder.png

We acknowledge the observiers at the NOT for carrying out this difficult 
observation.

[GCN OPS NOTE(10may09): The authors point out that there is a correction
to the coordinates given above (see GCN Circ 9340).]


GRB_name: GRB090510A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9339
SUBJECT: GRB 090510: Enhanced Swift-XRT position
DATE:    09/05/10 10:59:39 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 1675 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 090510, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 333.55271, -26.58266 which is equivalent
to:

RA (J2000): 22h 14m 12.65s
Dec (J2000): -26d 34' 57.6"

with an uncertainty of 1.4 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, arXiv:0812.3662).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB090510A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9340
SUBJECT: GRB 090510: correction to coordinates in GCN 9338
DATE:    09/05/10 14:32:45 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@astro.ku.dk>

D. Malesani (DARK/NBI) reports:

The coordinates of the afterglow reported in GCN 9338 (Olofsson et al.) 
are wrong. The correct ones (referenced to USNO-B1 stars, 0.3" error) are:

RA(J2000) = 22:14:12.56
Dec(J2000) = -26:34:59.0

These coordinates are 0.7" away from the UVOT position (Marshall & 
Hoversten, GCN 9332) and indeed consistent within their quoted error. 
The object identified in the finding chart posted at

http://www.astro.ku.dk/~malesani/GRB/090510/090510_finder.png

is correctly the afterglow.

I thank Frank Marshall for pointing out the mistake, and regret for any 
confusion that this may have created. No blame should go to the other 
co-authors of GCN 9338.


GRB_name: GRB090510A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9341
SUBJECT: GRB 090510: Swift XRT refined analysis
DATE:    09/05/10 15:41:02 GMT
FROM:    Dirk Grupe at PSU/Swift-XRT  <grupe@astro.psu.edu>

D. Grupe (PSU) and E. Hoversten (PSU) report on behalf of the Swift- 
XRT team:

We have analysed  XRT data for GRB090510 (Hoversten et al. GCN Circ.  
9331) up to
25ks after the burst
beginning 94.1 s after the BAT trigger. The data comprise 200 s in  
Windowed
Timing (WT) mode and 9.7 ks in Photon Counting (PC) mode.
The enhanced XRT position for this burst was given by Goad et al.
(GCN. Circ 9339).

The light curve can be modelled with a broken power-law decay with an
index of alpha=0.77+/-0.05, followed by a break at T+1470+/-160 s to
an alpha of 2.16 (+0.17, -0.14).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.57+/-0.08 with an
absorption column consistent with the Galactic
value of 1.66 x 10^20 cm^-2 (Kalberla et al. 2005). The PC mode spectrum
is consistent with this result.


If the light curve continues to decay with a power-law decay index of  
2.16,
the count rate at T+24 hours will be 1.3e-4 counts/s, corresponding to  
an
observed  0.3-10 keV flux of 6.1 x 10^-15 erg cm^-2 s^-1.



The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00351588.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090510A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9342
SUBJECT: GRB 090510: UVOT refined analysis
DATE:    09/05/10 16:59:54 GMT
FROM:    Paul Kuin at MSSL  <npkuin@googlemail.com>

N. P. M. Kuin (MSSL/UCL) and  E.A. Hoversten (PSU)  report on
behalf of the Swift UVOT team.

The Swift UltraViolet/Optical Telescope (UVOT) began observations of
the short hard burst GRB 090510 (Swift BAT trigger number 351588;
Hoversten et al. GCN Circ. 9331) on May 10, 2009, at 00:24:24 UT,
80 seconds after the BAT trigger with a settling exposure in the
UVOT v filter.

A new optical source was found by the UVOT (Marshall and Hoversten,
GCN Circ. 9332) for which we have a refined position (based on
matching the UVOT field sources to the USNO-B1 catalogue) of
RA, DEC =  333.55208, -26.58311, which is equivalent to:
RA = 22:14:12.5, DEC = -26:34:59.2, with an uncertainty of 1.5"
(90% confidence). The refined UVOT position is offset 1.6" from
the refined XRT position (Goad et al., GCN Circ. 9339) and is
consistent with the revised NOT position (Malesani, GCN Circ. 9340)
to within 0.2". 

GRB 090510 is detected in all UVOT filters, except perhaps in b,
which implies that the redshift is less than about 1.5. The
emission is seen to rise to a peak around 600s after the trigger.
The initial magnitude observed in the UVOT filters are given below:

Filter  Tstart(s)  Tstop(s)  Exposure(s)  Magnitude

wh       97        247          147.4     19.63 +/- 0.17
wh      588        608           19.5     18.76 +/- 0.22
wh     1167       1526           58.3     19.16 +/- 0.20
v        80       1410           97.3     18.46 +/- 0.33
b       564       1502           97.2    >19.62 (2.2 sigma)
u       712       1477          323.6     19.05 +/- 0.17
uvw1    687       1452           75.9     18.61 +/- 0.27
uvm2    662       1434           93.7s    18.10 +/- 0.22
uvw2    614       1552          115.4s    18.31 +/- 0.18

The values quoted above are on the UVOT Photometric System
(Poole et al, 2008, MNRAS 383,627). They are not corrected for the
expected galactic reddening of E(B-V) = 0.020 in the direction of
the burst (Schlegel et al. 1998).


GRB_name: GRB090510A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9343
SUBJECT: AGILE detection of GRB 090510
DATE:    09/05/10 19:38:52 GMT
FROM:    Marco Feroci at IASF/INAF  <sa.grb@iasf-roma.inaf.it>

F. Longo, E. Moretti, G. Barbiellini, E. Vallazza (INFN Trieste),
A. Giuliani (INAF/IASF Milan), S. Cutini, C. Pittori (ASDC) M.
Marisaldi, A. Bulgarelli, F. Gianotti, M. Trifoglio, G. Di Cocco,
C. Labanti, F. Fuschino, M. Galli (INAF/IASF Bologna),
A. Chen, S. Mereghetti, F. Perotti, P. Caraveo (INAF/IASF Milan),
Y. Evangelista, E. Del Monte, M. Feroci, I. Donnarumma, L. Pacciani, P.
Soffitta, E. Costa, F. Lazzarotto, I. Lapshov, M. Rapisarda(INAF/IASF  
Rome), A. Pellizzoni, M. Pilia (INAF/OA Cagliari), S. Vercellone  
(INAF/IASF Palermo),
M. Tavani, G. Pucella, F. D'Ammando, V.Vittorini, A. Argan, A. Trois,
G. Piano, S. Sabatini (INAF/IASF Rome), P. Picozza, A. Morselli (INFN  
Roma-2), M. Prest (Universita' dell'Insubria), P. Lipari, D. Zanello  
(INFN Roma-1), A. Rappoldi, P. Cattaneo (INFN Pavia) and P. Giommi,   
P. Santolamazza,
F. Verrecchia (ASDC) and L. Salotti (ASI), on behalf of the AGILE Team,
report:


AGILE detected the remarkable short GRB 090510 (Hoversten et al. GCN
#9331, Ohno et al. GCN #9334) at approximately 61 degrees off-axis.
An analysis of AGILE-GRID data shows an above 5-sigma detection of
gamma-ray emission above 100 MeV. The gamma-ray lightcurve above 100 MeV
shows emission during both the prompt phase and during a "delayed" phase.
Also the Mini-Calorimeter detected a very significant and structured
event lasting ~200 msec with emission well above 3 MeV.
The burst triggered also SuperAGILE, although outside the field of view.
This is the first short GRB with emission above 100 MeV detected by AGILE.


GRB_name: GRB090510A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9344
SUBJECT: Konus-Wind observation of GRB 090510
DATE:    09/05/11 13:37:31 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val@mail.ioffe.ru>

S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P.
Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind
team, report:

The short hard GRB 090510 (Swift-BAT trigger #351588: Hoversten et al.,
GCN 9331, Ukwatta et al., GCN 9337; Fermi-LAT trigger 263607783 / 
090510016: Ohno & Pelassa, GCN 9334) triggered Konus-Wind at T0=1381.547 
s UT (00:23:01.547).

The burst light curve shows a multipeaked structure with a duration of 
~0.4 s

As observed by Konus-Wind the burst
had a fluence of (2.42 +/- 0.37)x10^-5 erg/cm2,
and a 16-ms peak flux measured from T0+0.002 s
of (2.27 +/- 0.63)x10^-4 erg/cm2/s
(both in the 20 keV - 15 MeV energy range).

The spectrum of the most intense part
(from T0 to T0+0.192 s; it comprises ~75% of the total counts)
is well fitted (in the 20 keV - 15 MeV
range) by GRB (Band) model for which:
the low-energy photon index alpha = 0.11(-0.43, +0.48),
the high energy photon index beta = -1.61(-0.34, +0.15),
the peak energy E0 = 552(-249, +448) keV (chi2 = 28.6/31 dof).
Since beta > -2 we can establish only the lower limit on the peak energy 
  in the EF(E) spectrum: Ep > 912 keV.
The emission is clearly seen up to the end of the Konus-Wind energy 
range at 15 MeV.
All the quoted errors are at the 90% confidence level.

We note that since beta > -2 the bolometric fluence might be 
substantially higher than the given value.

The Konus-Wind light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB090510_T01381/

[GCN OPS NOTE(11may09):  The typo in the Subject-line was changed from "091005"
to "090510".]


GRB_name: GRB090510A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9345
SUBJECT: GRB 090510: correction to GCN 9344
DATE:    09/05/11 13:54:52 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val@mail.ioffe.ru>

V. Pal'shin on behalf of the Konus-Wind team, report:

"...the peak energy E0 = 552(-249, +448) keV (chi2 = 28.6/31 dof)."
in GCN 9344

should be read as:

"...the e-folding energy E0 = 552(-249, +448) keV (chi2 = 28.6/31 dof)."


GRB_name: GRB090502A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9346
SUBJECT: GRB 090502: Fermi GBM detection
DATE:    09/05/11 15:52:55 GMT
FROM:    Vandiver Chaplin at UAH/Fermi-GBM  <chapliv@email.uah.edu>

V.Chaplin (UAH) reports on behalf of the
Fermi GBM Team:

"At 18:39:34.64 UT on 02 MAY 2009, the Fermi Gamma-ray
Burst Monitor (GBM) triggered and located GRB 090502
(trigger 262982376 / 090502777). The on-ground calculated
location, using the GBM trigger data, is
RA = 267.8, Dec = -20.3 (J2000 degrees, equivalent to
J2000 17h 51m, -20d 18'), with a statistical uncertainty
of 7.4 degrees (radius, 1-sigma containment, statistical
only; there is additionally a systematic error which is
currently estimated to be 2 to 3 degrees). The angle from
the Fermi LAT boresight is 77 degrees.

The GBM light curve shows a multi-peaked burst with a
duration (T90) of about 66.2 s (8-1000 keV). The
time-averaged spectrum from T0-11.6 to T0+62.1 s
is best fit by a power-law with an exponential cut-off,
with alpha = -1.1 +/- 0.3 and E-peak = 63.2 +/- 8.7 keV,
(chi squared 227.86 for 241 d.o.f.)

The fluence (8-1000 keV) in this time interval is
(3.5 +/- 0.9)E-08 erg/cm^2. The 1-second peak photon
flux starting from T0+37.5 is 6.2 +/- 0.9 ph/s-cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090510B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9347
SUBJECT: GRB 090510B: Fermi GBM detection
DATE:    09/05/11 16:02:42 GMT
FROM:    Arne Rau at MPE  <arau@mpe.mpg.de>

Arne Rau (MPE) reports on behalf of the Fermi GBM Team:

"At 07:47:39.51  UT on 10 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090510B (trigger 263634461  / 090510325).

The on-ground calculated location, using the GBM trigger
data, is RA = 269.4 , DEC = -57.9 (J2000 degrees,
equivalent to 17h 57m, -57d 56'), with an uncertainty
of 11.6 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).

The GBM light curve shows a single peak  with a duration (T90)
of about 7s (8-1000 keV).

The angle from the Fermi LAT boresight is 100 degrees.
Since the source is weak, the time-averaged spectrum is poorly 
constrained."


GRB_name: GRB090509A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9349
SUBJECT: GRB 090509, further Swift-BAT refined analysis
DATE:    09/05/11 17:15:49 GMT
FROM:    Hans Krimm at NASA-GSFC  <hans.krimm@nasa.gov>

H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), and J. R. Cummings (GSFC/UMBC) 
for the Swift-BAT team.

Here we report on further analysis of GRB 090509 (Grupe et al., GCN Circ. 9325) 
based on additional event data received since GCN Circ. 9335 (Tueller et al.) 
was issued.  The results given here supersede those from GCN Circ. 9335.

Using the data set from T-239 to T+316 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090509 (trigger #351525). The BAT 
ground-calculated position is
RA, Dec = 241.422, -28.385 deg which is
    RA(J2000)  =  16h 05m 41.3s
    Dec(J2000) = -28d 23' 04.4"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 29%.

The mask weighted light curve consists of two sets of peaks widely separated in 
time.  The first complex contains multiple overlapping peaks starting at ~T-4 
sec, peaking at ~T+21 sec, and ending at ~T+40 sec.  The second complex also 
contains multiple overlapping peaks starting at ~T+240 sec, peaking at ~T+250 
sec and continuing until at least ~T+300 sec, when a pre-planned slew caused the 
source to move out of the BAT field of view.  However until ~T+950 sec the 
source was at a location outside the field of view where high energy (> 50 keV) 
photons from the source could have penetrated the BAT shield and contributed to 
the non-maskweighted light curve.  Examination of the raw light curve shows no 
additional peaks comparable in intensity to those described above.  We cannot 
rule out weak source activity or activity below about 50 keV. Based on the 
available data, T90 (15-350 keV) is 335 +- 32 sec (estimated error including 
systematics).

The time-averaged spectrum from T-62.6 to T+298.7 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.75 +- 0.20.  The fluence in the 15-150 keV band is 3.3 +- 0.4 x 10-6 erg/cm2.
The 1-sec peak photon flux measured from T+20.73 sec in the 15-150 keV band
is 1.5 +- 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/351525/BA/


GRB_name: GRB090510A
Detection_method: Fermi LAT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9350
SUBJECT: GRB 090510: Fermi-LAT follow-up analysis
DATE:    09/05/11 21:33:14 GMT
FROM:    Nicola Omodei at INFN(Pisa)/GLAST  <nicola.omodei@pi.infn.it>

N. Omodei (INFN Pisa), J. Granot (University of Hertfordshire),
P. Meszaros (PSU), J. McEnery (GSFC), F. Piron (LPTA), S. Razzaque (NRL)
H. Tajima (SLAC), V. Vasileiou (GSFC/UMBC), D. Williams (UCSC),
report on behalf of the Fermi LAT Collaboration.

A follow-up analysis of the short bright Fermi GRB 090510 (Ohno et al.,
GCN 9334, Guiriec et al., GCN 9336) has been performed by the Fermi-LAT
team.

Fermi LAT has detected more than 50 events above 100 MeV (>10 above 1
GeV) during the first second and more than 150 events above 100 MeV (>20
above 1 GeV) in the first minute after the GBM trigger.
All these events are positionally consistent (within the 95% containment
radius of the LAT point spread function) with the position reported by
Swift (Goad et al. GCN 9339). They indicate extended emission above GeV
energies, making this burst an absolute priority for follow-up searches,
especially a redshift determination.

The points of contact for this burst is:
Masanori Ohno ohno@astro.isas.jaxa.jp

The Fermi LAT is a pair conversion telescope designed to
cover the energy band from 20 MeV to greater than 300 GeV.
It is the product of an international collaboration between NASA and DOE
in the U.S. and many scientific institutions across France, Italy, Japan 
and Sweden.


GRB_name: GRB090510A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9351
SUBJECT: GRB 090510: Swift/UVOT host galaxy candidates
DATE:    09/05/11 23:50:50 GMT
FROM:    Paul Kuin at MSSL  <npkuin@googlemail.com>

N. P. M. Kuin (MSSL/UCL), S. Oates (MSSL/UCL), M. De Pasquale (MSL/UCL),
E.A. Hoversten (PSU), and F. Marshall (GSFC) report on behalf of the
Swift UVOT team.

The Swift UltraViolet/Optical Telescope (UVOT) continued observations of
the short hard burst GRB 090510 (Swift BAT trigger number 351588;
Hoversten et al. GCN Circ. 9331) today. The summed image in the white
filter taken between 92.7ks and 127.6 ks shows that the source has faded
from the initial magnitude of wh = 18.76 mag at T+800 and is now possibly
detected at 3.3 sigma at a magnitude of 22.9+/-0.3.  Observations between
T+2000s and T+100ks show a decay index of about 1.  There are also two
nearby sources at the 6 sigma level detectable, which we consider to be
possible hosts of GRB 090510.

The first, nearest, candidate is at  position RA, DEC = 333.55220, -26.584525
(22h 14m 12.53s, -26d 35m 04.29s (J2000)), with a diameter of 2.3", and the
second, more extended, candidate is found at position  RA, DEC =
333.54963, -26.582294 (22h 14m 11.91s, -26d 34m 56.26s (J2000)), is more
elongated with a diameter of about 3.1". The estimated positional accuracy
is 0.7" for both sources. Both sources have a wh magnitude of 21.61 +/- 0.17.

We encourage follow-up observations.

We would like to make a correction:  The UVOT positional error on GRB 090510
quoted in GCN 9342 was too large. The correct uncertainty in the GRB position
was 0.61" (90% confidence radius).


GRB_name: GRB090510A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9352
SUBJECT: GRB 090510: GROND observations
DATE:    09/05/12 15:19:57 GMT
FROM:    Thomas Kruehler at MPE/MPI  <kruehler@mpe.mpg.de>

F. Olivares (MPE Garching), S. Klose (Tautenburg), T. Kruehler, J. Greiner 
(both MPE Garching) report on behalf of the GROND team:

GROND, mounted at the 2.2m on La Silla, observed the field of GRB 090510, 
detected by Swift (Hoversten et al., GCN 9331), Fermi GBM (Guiriec et al., 
GCN 9336) and LAT (Ohno & Pelassa, GCN #9334), AGILE (Longo et al., GCN 
9343) and Konus-Wind (Golenetskii et al., GCN 9344), in g'r'i'z'JHK 
starting at 6:34 UT on 10 May 2009.

We detect the afterglow reported by Marshall & Hoversten (GCN #9332) and 
Olofsson et al. (GCN #9338) in the optical bands. At a midtime of 9.0 h 
after the burst, we measure the following AB magnitudes of the afterglow 
and upper limits in stacked images

g' = 23.5 +/- 0.3
r' = 23.0 +/- 0.1
i' = 22.8 +/- 0.1
z' = 22.6 +/- 0.1
J > 21.8
H > 21.4
K > 20.7

calibrated against the GROND zeropoints and 2MASS field stars. We caution 
that the photometry might be contaminated by the nearby source mentioned by 
Olofsson et al. (GCN #9338).

Together with the magnitude reported by NOT (Olofsson et al. GCN #9338), 
this implies a rapid early fading with an index of ~2 during this epoch, 
which is compatible to the X-ray afterglow at a similar time interval 
(Grupe & Hoversten, GCN #9341). A late flattening of the optical light 
curve is then indicated by the UVOT detection (Kuin et al. #GCN 9351).


GRB_name: GRB090510A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9353
SUBJECT: GRB090510: VLT/FORS2 spectroscopic redshift
DATE:    09/05/12 17:42:34 GMT
FROM:    Arne Rau at MPE  <arau@mpe.mpg.de>

Arne  Rau (MPE  Garching), Sheila  McBreen (UCD/MPE  Garching), Thomas
Kruehler, and Jochen Greiner (both MPE Garching) report:

We present follow-up optical spectroscopy of the short Swift/Fermi GRB
090510 (Hoversten et al., GCN  9331; Ohno & Pelassa, GCN 9334; Guiriec
et al.,  GCN 9336) using  VLT/FORS2 (PI McBreen). Observations  of the
optical source  consistent with position of the  afterglow (Marshall &
Hoversten, GCN 9332;  Olofsson et al., GCN 9338;  Olivares et al., GCN
9352) started  on May  12 08:17UT.  A  total of three  30min exposures
with the 300I grism  were obtained, covering an approximate wavelength
range of 6000-10000 Angstroms.

Preliminary analysis of the spectra reveals two emission lines at 7093
and 9250 Angstroms,  which we identify as [OII] and  Hbeta at a common
redshift of z=0.903 +/- 0.003. Furthermore, there are indications of a
spectral break  in the continuum  around 7600 Angstroms,  suggesting a
possible 4000A break at the same redshift.

The detection of  emission lines and the possible  4000A break suggest
the dominance of the underlying  host galaxy over the afterglow at the
time of our observations. It also confirms that host galaxies of short
GRBs are not  all old and dead ellipticals but  instead drawn from the
underlying  field galaxy  distribution (e.g.,  Berger 2009,  ApJ, 690,
231).

In the  acquisition image the center  of the host is  0.7" offset with
respect to the NOT refined afterglow position, which corresponds to 5.5 
kpc at a
z=0.903.

At a redshift of z=0.903, the isotropic equivalent energy of the burst
is  3.8E52 erg in the 1 keV - 10 MeV rest  frame (using  the Fermi/GBM
spectral parameters of Guiriec et  al., GCN 9336).  The peak energy of
the best fit  GBM Band function model  is 8.4 +/- 0.8 MeV  in the rest
frame.

We  acknowledge excellent support  from the  ESO staff,  in particular
F. Selman and I. Condor.


GRB_name: GRB090510A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9354
SUBJECT: GRB 090510, Radio limits
DATE:    09/05/13 16:00:14 GMT
FROM:    Dale A. Frail at NRAO  <dfrail@nrao.edu>

D. A. Frail (NRAO) and P. Chandra (RMC) report on behalf of a
larger collaboration:

"We have used the Very Large Array (VLA) to image a field toward the
short, bright Fermi-LAT burst GRB 090510 (GCN # 9350, 9334). The VLA
observed at a frequency of 8.46 GHz on three epochs, May 11.48, May
12.48 and May 13.52 UT. There is no radio source detected at the
position of the optical afterglow (GCN #9340). Adding the data
together for all three epochs, the 3-sigma limit is 84 uJy. No further
observations are planned.

The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."


GRB_name: GRB090510A
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9355
SUBJECT: GRB 090510: Suzaku WAM observation of the prompt emission
DATE:    09/05/14 08:52:46 GMT
FROM:    Norisuke Ohmori at Miyazaki U  <ohmori@astro.miyazaki-u.ac.jp>

N. Ohmori, K. Noda, E. Sonoda, M. Yamauchi, K. Kono, H. Hayashi,
A. Daikyuji, Y. Nishioka (Univ. of Miyazaki),
M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA),
K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y. E. Nakagawa,
T. Tamagawa (RIKEN), S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.),
T. Uehara, Y. Hanabata, T. Takahashi, Y. Fukazawa (Hiroshima U.),
W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda,
T. Sugasahara (Saitama U.), Y. Urata (NCU),
T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo),
on behalf of the Suzaku WAM team, report:

The short hard GRB 090510 detected by the Fermi-LAT (Swift/BAT trigger
 #351588; Hoversten et al., GCN 9331,Fermi-LAT trigger #263607783;
 Ohno et al., GCN 9334) 
 triggered the Suzaku Wide-band All-sky Monitor (WAM) 
 which covers an energy range of 50 keV - 5 MeV at 00:23:00 UT (=T0).

The observed light curve shows a multi-peaked structure starting at T0-0.1s, 
 ending at T0+0.9s  with a duration (T90) of about 0.33 seconds.
The emissions was clearly detected at least up to 5 MeV.

However, since the incident angle of this burst to the WAM is off-axis, we
 cannot perform a reliable spectral analysis at this moment. 
We are now improving our detector response from such an off-axis direction.

The light curves for this burst are available at:

 http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html


GRB_name: GRB090515A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9356
SUBJECT: GRB 090515: Swift detection of a short burst
DATE:    09/05/15 04:56:51 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

A. P. Beardmore (U Leicester), J. A. Kennea (PSU),
C. B. Markwardt (CRESST/GSFC/UMD), P. T. O'Brien (U Leicester),
K. L. Page (U Leicester), D. M. Palmer (LANL),
B. A. Rowlinson (U Leicester), M. H. Siegel (PSU),
M. Stamatikos (NASA/ORAU) and T. N. Ukwatta (GSFC/GWU) report on
behalf of the Swift Team:

At 04:45:09 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090515 (trigger=352108).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is RA, Dec 164.171, +14.456 which is 
   RA(J2000) = 10h 56m 41s
   Dec(J2000) = +14d 27' 22"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single short spike
structure with a duration of about 0.1 sec.  The peak count rate
was ~10000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 04:46:13.3 UT, 63.8 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 164.15224, 14.44099 which
is equivalent to:
   RA(J2000)  = 10h 56m 36.54s
   Dec(J2000) = +14d 26' 27.6"
with an uncertainty of 4.8 arcseconds (radius, 90% containment). This
location is 84 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of
1.94e+20 cm^-2 (Kalberla et al. 2005). 

The initial flux in the 2.5 s image was 5.22e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 72 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.02. 

Burst Advocate for this burst is A. P. Beardmore (apb AT star.le.ac.uk). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090515A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9357
SUBJECT: GRB 090515: ROTSE-III Optical Limits
DATE:    09/05/15 05:08:31 GMT
FROM:    Wiphu Rujopakarn at U AZ/Steward  <wiphu@as.arizona.edu>

W. Rujopakarn (Steward Observatory), B. E. Schaefer (Louisiana State), and
E.S. Rykoff (UCSB), report on behalf of the ROTSE collaboration:

ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB
090515 (Swift trigger 352108; Beardmore et al., GCN 9356), producing
images beginning 6.5 s after the GCN notice time. An automated response
took the first image at 04:45:27.5 UT, 18.0 s after the burst, under fair
conditions. We took 10 5-sec and 10 20-sec exposures. These unfiltered
images are calibrated relative to USNO A2.0 (R). Imaging is on going.

Comparison to the DSS (second epoch) reveals no new sources within the
3-sigma Swift/BAT error circle or the XRT error circle, for both single
images and coadding into sets of 10. Individual images have limiting
magnitudes ranging from 16.4-17.8; we set the following specific limits.

start UT       end UT      t_exp(s)   mlim   t_start-tGRB(s)  Coadd?
--------------------------------------------------------------------
04:45:27.5   04:45:32.5         5     16.4           18.0       N
04:45:27.5   04:46:34.6        67     18.4           18.0       Y


GRB_name: GRB090515A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9358
SUBJECT: GRB 090515: KAIT optical upper limits
DATE:    09/05/15 05:57:53 GMT
FROM:    Ryan Chornock at UC Berkeley  <chornock@astro.berkeley.edu>

W. Li, R. Chornock, and A. V. Filippenko (UC Berkeley) report on
behalf of the KAIT GRB team:

The Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory responded to
the Swift trigger of GRB 090515 (Beardmore et al., GCN 9356) and began a
sequence of filtered and unfiltered 20s images followed by a set of three 180s
unfiltered images.  We detect no new source within the XRT error circle
(Beardmore et al., GCN 9356).  Individual unfiltered 20s exposures starting at
04:59:09 UT have 3-sigma limiting magnitudes (calibrated to USNO B1) of about
mag 19.1.  Our combined set of 3x180s unfiltered images has an upper limit of
about mag 20.5 at a midpoint of 05:19:47 UT.


GRB_name: GRB090515A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9359
SUBJECT: GRB 090515: PAIRITEL Upper Limits
DATE:    09/05/15 06:42:34 GMT
FROM:    Adam Morgan at PSU/Swift-UVOT  <qmorgan@gmail.com>

A. N. Morgan, B. E. Cobb, C. Klein, and J. S. Bloom (UC Berkeley) report:

We observed the field of GRB 090515 (Beardmore et al. 2009, GCN 9356)
with the 1.3-m PAIRITEL located at Mt Hopkins, Arizona.  Observations
began at 2009-05-15 05:11 UT, 26 minutes after the Swift Trigger.  We
detect no afterglow at the XRT position in a mosaic with an effective
exposure time of ~330 seconds.

The preliminary photometry (calibrated to 2MASS) yields:

post_burst
t_mid(min) exp(s)  filt  U. Limit (3 sig)
30         330     J     > 18.0
30         330     H     > 17.2
30         330     K     > 15.1

All magnitudes are given in the Vega system. No correction for
Galactic extinction has been made to the above reported values.


GRB_name: GRB090515A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9360
SUBJECT: GRB 090515: Super-LOTIS Upper Limits
DATE:    09/05/15 08:00:24 GMT
FROM:    Grant Williams at Steward Observatory  <ggwilli@gmail.com>

G. G. Williams (MMTO), A. Updike (Clemson), and P. A. Milne (Steward
Observatory), on behalf of the Super-LOTIS Collaboration, report:

The robotic 0.6-m Super-LOTIS telescope began observing the error box
of GRB 090515 (Swift Trigger 352108, Beardmore et al. GCN 9356) at
04:45:52 UT, 43 seconds after the trigger.  Our initial observations
include 5 x 10s exposures, 5 x 20s exposures, and 30 x 60s exposures,
all in the R-band.

We do not detect any variable sources or afterglow candidates within
the XRT error box in our earliest exposure to the following 3-sigma
limiting magnitude determined using nearby USNO-B1.0 stars.  We also
do not detect any afterglow candidate in later images and sets of
combined images:

t_start (UT)     exp t (s)     t_start-t_0 (s)     Limit
----------------------------------------------------------------
04:45:52         10            43                    R > 17.7


GRB_name: GRB090515A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9361
SUBJECT: GRB 090515: WIYN NIR Upper Limit
DATE:    09/05/15 08:47:58 GMT
FROM:    Adria C. Updike at Clemson U  <aupdike@clemson.edu>

Adria C. Updike, Ginger Bryngelson (Clemson University) and Peter A. Milne
(Steward Observatory) report:

We observed the field of GRB 090515 (GCN 9356, Beardmore et al.) with the
3.5m WIYN telescope and the NIR imager WHIRC located at Kitt Peak National
Observatory beginning 1 hour after the trigger.  Observations consisted
of J-band exposures at high airmass.  In a stacked image consisting of 20
x 2min J-band exposures (T_0 = 1.4 hours after trigger), we detect no new
objects down to a limiting magnitude of J > 19.0 mag (upon comparison to
the 2MASS catalog).  No further observations are planned.


GRB_name: GRB090515A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9362
SUBJECT: GRB 090515: Gemini-N upper limit
DATE:    09/05/15 09:00:11 GMT
FROM:    Antonino Cucchiara at PSU  <cucchiara@astro.psu.edu>

A. Cucchiara, D. B. Fox (PSU), N. Tanvir (U. Leicester), E. Berger 
(Harvard U.),
John Graham (STScI / JHU) and A. Levan (U. Warwick) report:

On May 15.28 UT we observed the field of the short GRB 090515 (Beardmore 
at al,
GCN 9356) with Gemini GMOS-N. We took a sequence of 6 images of 300 sec
each in R band.

No clear afterglow candidate has been found in the XRT error circle (GCN 
9356)
at the limiting magnitude of R ~ 25.4.

We also note the presence of a galaxy on the north edge of the XRT error 
circle,
at the following position:

RA: 10:56:36.46
Dec: +14:26:31.91

with a 0.3 arcsecond error in both coordinates.
The magnitude of this galaxy is R = 22.90 +- 0.18 (calibrated using the 
SDSS star
at RA = 10:56:35.74 , Dec = 14:26:49.6).


We thank the Gemini staff for performing these observations.


GRB_name: GRB090509A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9363
SUBJECT: GRB 090509 - Zadko Telescope observations
DATE:    09/05/15 11:29:00 GMT
FROM:    David Coward at U of Western Aus.  <coward@physics.uwa.edu.au>

SUBJECT: GRB 090509 - Zadko Telescope observations
FROM: D.M Coward at UWA

Liang Yan and A. Imerito report on behalf of the Zadko Telescope Team:

D.M. Coward, Liang Yan, A. Imerito, T.P. Vaalsta, A. Ahmet, J. Zadko,  
D. Blair,
R. Burman, P. Luckas, S. Gordon, K. Frost, A. Fletcher, J. Moore
(University of Western Australia)
M. Todd, M. Zadnik (Curtin University)
M. Boer, A. Klotz (TAROT)

The 1 m Zadko Telescope team observed the field of GRB 090509  
(trigger=351525,
D. Grupe et al. GCN 9325) 8hr after the Swift trigger.

We stacked 48x5s unfiltered images of the field from
13:10:32 to 13:24:16 UT (2009-05-09)

No candidate afterglow was observed at the GROND position (GCN 9326)  
nor at
the BAT-refined position (GCN 9349), down to an Rmag of approx. 17.6.  
(The OA
magnitude limit was estimated by comparing nearby USNO-B1 reference  
stars.)

The Zadko Telescope is currently being commissioned.
This message is quotable in publications

Dr David Coward
Senior Research Fellow
School of Physics
University of Western Australia
Crawley WA 6009

Tel: +61 8 6488 4563
Mobile 0423981240
Fax: +61 8 6488 1170


GRB_name: GRB090515A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9364
SUBJECT: GRB 090515: Swift-BAT refined analysis
DATE:    09/05/15 12:44:58 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
A. P. Beardmore (U Leicester), J. R. Cummings (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC),
T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data sets from T-60 to T+243 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 090515 (trigger #352108)
(Beardmore, et al., GCN Circ. 9356).  The BAT ground-calculated position is
RA, Dec = 164.166, 14.469 deg, which is 
   RA(J2000)  =  10h 56m 39.8s 
   Dec(J2000) = +14d 28' 09.5" 
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 86%.
 
The mask-weighted light curve shows a single peak with a slightly longer
fall time than rise time. The total width is about 0.075 sec.
T90 (15-350 keV) is 0.036 +- 0.016 sec (estimated error including systematics).
 
The time-averaged spectrum from T+0.008 to T+0.056 sec is best fit by
a simple power-law model.  The power law index of the time-averaged
spectrum is 1.6 +- 0.2.  The fluence in the 15-150 keV band is
2.1 +- 0.4 x 10^-8 erg/cm2.  The 1-sec peak photon flux measured from
T-0.30 sec in the 15-150 keV band is 5.7 +- 0.9 ph/cm2/sec.  All the
quoted errors are at the 90% confidence level.
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/352108/BA/


GRB_name: GRB090515A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9365
SUBJECT: GRB 090515: Swift-BAT refined spectral analysis
DATE:    09/05/15 15:29:10 GMT
FROM:    Takanori Sakamoto at NASA/GSFC  <takanori.sakamoto-1@nasa.gov>

T. Sakamoto (GSFC/UMBC), A. P. Beardmore (U Leicester) 
on behalf of the Swift-BAT team

Based on a further analysis of the BAT spectrum of GRB 090515 
(Barthelmy, et al. , GCN Circ. 9364), we found that the spectrum shows 
a significant improvement of chi2 by a power-law with an exponential 
cutoff (chi squared 52.55 for 56 d.o.f.) over a simple power-law 
(chi squared 58.63 for 57 d.o.f.).  This fit gives a photon index 
-0.05 +- 1.36, and Epeak of 64 +- 23 keV.  For this model 
the total fluence in the 15-150 keV band is 2.0 +- 0.3 x 10^-8 erg/cm2.  
All the quoted errors are at the 90% confidence level.


GRB_name: GRB090509A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9366
SUBJECT: GRB 090509: Fermi GBM observation
DATE:    09/05/15 15:33:09 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

A. von Kienlin (MPE) and Sheila McBreen (UCD/MPE) 
report on behalf of the Fermi GBM Team: 

"At 05:10:05.72 UT on 09 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090509 (trigger 263538607 / 090509215)
which was also detected by the SWIFT-BAT (Grupe et al. 2008, GCN 9325; 
Krimm et al., GCN 9349). The GBM on-ground location is consistent 
with the Swift position.

The angle from the Fermi LAT boresight is 75 degrees.

The GBM light curve consists of two widely separated multi-peaked 
emission periods with a duration (T90) of about 295 s (8-1000 keV). 
The time-averaged spectrum of the first emission complex from 
T0-3.072 to T0+24.576  s is well fit by a power law function with 
an exponential high energy cutoff.  The power law index is -0.90 +/- 0.16 
and the cutoff energy, parameterized as Epeak, is 343 +/- 93 keV 
(chi squared 375 for 360 d.o.f.). 
The time-averaged spectrum of the second emission complex from 
T0+239.619 s to T0+288.772 s is best fit by a simple power 
law function with index -1.55 +/- 0.07 (chi squared 328 for 361 d.o.f.).

The summed event fluence (8-1000 keV) of both time intervals is 
(8.4 +/- 0.4)E-06 erg/cm^2. The 1-sec peak photon flux measured 
starting from T0+18.432 s in the 8-1000 keV band 
is 3.1 +/- 0.3  ph/s/cm^2.

The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090515A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9367
SUBJECT: GRB 090515: Enhanced Swift-XRT position
DATE:    09/05/15 16:44:21 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 2254 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 090515, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 164.15047, +14.44174 which is equivalent
to:

RA (J2000): 10h 56m 36.11s
Dec (J2000): +14d 26' 30.3"

with an uncertainty of 2.7 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, arXiv:0812.3662).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB090515A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9368
SUBJECT: GRB 090515: Swift-XRT refined analysis
DATE:    09/05/15 18:58:27 GMT
FROM:    Andy Beardmore at U Leicester  <apb@star.le.ac.uk>

A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the
Swift-XRT team :

We have analysed 4.5 ks of XRT data for GRB 090515 (Beardmore et
al. GCN Circ. 9356), from 70 s to 11.5 ks after the BAT trigger. The
data comprise 132 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode.  The enhanced XRT position for this
burst was given by Osborne et al. (GCN Circ. 9367).

Initially, the light curve follows a shallow decay from a rate of 30
count s^-1 (at T+70 s), with a decay index of 0.59, out to
approximately T+245 s. The count rate then drops by a factor of
~250 in the next ~70 s (i.e. suggesting a decay index in excess of 10
at this time). The burst is no longer detected beyond the first orbit
to a 3 sigma count rate upper limit of 0.0058 count s^-1 (from T+5.7
to T+11.5 ks).

A spectrum formed from the WT mode data (from T+70 to T+195 s) can be
fitted with an absorbed power-law with a photon spectral index of
1.88 +/- 0.14. The best-fitting absorption column is (6.1 +3.0 -2.8) x
10^20 cm^-2, in excess of the Galactic value of 1.9 x 10^20 cm^-2
(Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV
flux conversion factor deduced from this spectrum is 3.6 x 10^-11 (4.1
x 10^-11) erg cm^-2 count^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00352108.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090515A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9369
SUBJECT: GRB 090515: Swift/UVOT Observations
DATE:    09/05/15 20:10:18 GMT
FROM:    Michael Siegal at Swift/PSU  <siegel@astro.psu.edu>

M. H. Siegel (PSU) and A. P. Beardmore (Leicester) report on behalf
of the Swift/UVOT team.

The Swift/UVOT began observing the field of GRB 090515 67s after
the BAT trigger (Beardmore et al., GCN Circ. 9356).  Data summed
from the first and second orbits does not reveal a source at the
refined position of the X-ray afterglow (Osborne et al., GCN Circ.
9367).

The 3-sigma upper limits for the finding chart (fc) and
summed exposures are reported below:

FILTER     T_start(s)  T_stop     Exposure     Mag/3UL
=============================================================
white fc       67        216        146       > 20.35
white          67       2389        488       > 21.24
white        5901      13321        401       > 21.12

v             608       2439        213       > 19.27
v            6311       7947        393       > 19.62

b             534       2365        194       > 20.15
b            5696      13291        688       > 20.70

u             278        528        245       > 19.83
u            6926      12386        491       > 20.40

uvw1          657       2488        214       > 19.83
uvw1         6722       8290        327       > 20.01

uvm2          805       2291         97       > 19.07
uvm2         6516       8151        393       > 20.16

uvw2          583       2414        213       > 20.11
uvw2         6107       7742        393       > 20.48
=================================================================

The above magnitudes are not corrected for the Galactic extinction
corresponding to a reddening of E_{B-V} = 0.02 (Schlegel et al.,
1998, ApJS, 500, 525). The photometry is on the UVOT photometric
system described in Poole et al. (2008, MNRAS, 383, 627).


GRB_name: GRB090515A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9370
SUBJECT: GRB 090515: MMT/MMIRS NIR Upper Limit
DATE:    09/05/15 22:59:17 GMT
FROM:    Grant Williams at Steward Observatory  <ggwilli@gmail.com>

B. McLeod (CfA), G. Williams (MMTO) on behalf of the MMIRS
commissioning team report:

We observed the field of GRB 090515 (Beardmore et al. 2009, GCN 9356)
with the MMIRS instrument on the 6.5-m MMT telescope. Observations
began at 06:44 UT, approximately 119 minutes after the Swift trigger.
We obtained 27 x 30 second exposures in the K-band. We do not detect
any afterglow candidate in the XRT error circle in the combined image
to the following 5-sigma limiting magnitude determined using nearby
2MASS stars:

t_start (UT)   exp t (s)   t_start-t_0   Limit
-----------------------------------------------------------
06:44    27x30       119 min   K > 19.3


GRB_name: GRB090515A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9371
SUBJECT: GRB 090515: ROVOR Upper Limit
DATE:    09/05/15 23:34:03 GMT
FROM:    J. Ward Moody at BYU  <rovor.byu@gmail.com>

Cameron J. Pace, Richard L. Pearson, and J. Ward Moody report for
Brigham Young Universitys ROVOR team:

We report our observations in the field of GRB 090515 (Swift trigger
352108, Beardmore et al., GCN 9356) beginning 37.73 minutes post-burst
at 05:22:53.376 UT.

Using the 0.41m ROVOR telescope in Delta, Utah, we combined 70 x 60
second exposures in the R-band. No detection of an afterglow was
obtained after stacking the images. An upper limit of 21.4  0.1 mag
was found by calibrating the frames using stars in the MRK 501 field.


GRB_name: GRB090515A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9372
SUBJECT: GRB 090515: Lick Upper Limits
DATE:    09/05/15 23:42:40 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>

D. A. Perley, M. Kislak, and M. Ganeshalingam (UC Berkeley) report:

We imaged the field of short GRB 090515 (Beardmore et al., GCN 9356) 
with the Nickel 40-inch telescope at Lick Observatory starting at 
04:52:57 UT (7.8 minutes after the trigger) in BVRI filters.  No object 
is detected within the XRT error circle (Osborne et al., GCN 9367) in 
any exposure or in stacked frames.  Approximate upper limits (relative 
to SDSS):

tmid(min) exp(sec) filt  lim(mag)
8.3       60        B  > 19.9
10.0      60        V  > 20.5
22.5      720       I  > 20.3
38.1      600       R  > 21.3


GRB_name: GRB090515A
Detection_method: VLA Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9373
SUBJECT: GRB 090515:  VLA observations
DATE:    09/05/16 04:32:00 GMT
FROM:    Edo Berger at Harvard  <eberger@cfa.harvard.edu>

E. Berger and W.-f. Fong (Harvard) report:

"We observed the field centered on the XRT error circle of the short GRB 
090515 (GCNs #9356,9367) with the VLA at a frequency of 8.46 GHz 
starting on 2009 May 16.066 UT (20.8 hours post burst).  We do not 
detect any sources within the XRT error circle to a 3-sigma limit of 60 
microJy."


GRB_name: GRB090516A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9374
SUBJECT: GRB 090516: Swift detection of a burst
DATE:    09/05/16 08:49:10 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

B. A. Rowlinson (U Leicester), A. P. Beardmore (U Leicester),
P. A. Evans (U Leicester), C. Guidorzi (U Ferrara),
J. A. Kennea (PSU), P. T. O'Brien (U Leicester),
K. L. Page (U Leicester), D. M. Palmer (LANL),
P. Romano (INAF-IASFPA) and T. Sakamoto (NASA/UMBC) report on behalf
of the Swift Team:

At 08:27:50 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090516 (trigger=352190).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 138.271, -11.858 which is 
   RA(J2000) = 09h 13m 05s
   Dec(J2000) = -11d 51' 27"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a multiple-peaked
structure with a duration of at least 150 sec.  The peak count rate
was ~1000 counts/sec (15-350 keV), at ~5 sec after the trigger, with 
additional prominent peaks at T+35, T+90 and T+135. 

The XRT began observing the field at 08:30:37.4 UT, 166.7 seconds after
the BAT trigger. Using promptly downlinked data we find a bright, fading,
uncatalogued X-ray source located at RA, Dec 138.26119, -11.85480 which
is equivalent to:
   RA(J2000)  = 09h 13m 2.69s
   Dec(J2000) = -11d 51' 17.3"
with an uncertainty of 4.1 arcseconds (radius, 90% containment). This
location is 36 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of
4.47e+20 cm^-2 (Kalberla et al. 2005). 

The initial flux in the 0.1 s image was 1.96e-08 erg cm^-2 s^-1 (0.2-10
keV). 


UVOT took a finding chart exposure of 150 seconds with the White filter
starting 176 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.05. 




Burst Advocate for this burst is B. A. Rowlinson (bar7 AT star.le.ac.uk). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090516A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9375
SUBJECT: GRB 090516: Faulkes Telescope South optical afterglow
DATE:    09/05/16 10:08:59 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi (U. Ferrara), I. A. Steele, A. Melandri, D. Bersier,
C.J. Mottram, C.G.  Mundell, R.J. Smith (Liverpool JMU),
A. Gomboc (U. Ljubljana),  P. O'Brien, N. Bannister,
N. Tanvir (U. Leicester) on behalf of a large collaboration report:

The 2-m Faulkes Telescope South reacted to the Swift burst
GRB 090516 (trigger=352190, Rowlinson et al. GCN 9374).

Observations started about 16.9 min after the trigger time with filters
BRi. Within the XRT error circle we found a fading source at the following
position (J2000):

RA:   09:13:02.62
Dec: -11:51:15.4

with an initial approximate magnitude of R~19 at 17 minutes post trigger.


GRB_name: GRB090516A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9376
SUBJECT: GRB 090516: Enhanced Swift-XRT position
DATE:    09/05/16 14:06:48 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 2534 s of XRT Photon Counting mode data and 5 UVOT
images for GRB 090516, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 138.26050, -11.85442 which is equivalent
to:

RA (J2000): 09h 13m 2.52s
Dec (J2000): -11d 51' 15.9"

with an uncertainty of 1.5 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, arXiv:0812.3662).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB090516A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9377
SUBJECT: GRB 090516: Swift/UVOT Observations
DATE:    09/05/16 18:45:43 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@astro.psu.edu>

M. H. Siegel (PSU) and B. A. Rowlinson (Leicester) report on behalf
of the Swift/UVOT team.

The Swift/UVOT began observing the field of GRB 090516 171s after
the BAT trigger (Beardmore et al., GCN Circ. 9374).  Data summed
from the first and second orbits does not reveal a source at the
refined position of the X-ray afterglow (Beardmore et al., GCN Circ.
9376).

The 3-sigma upper limits for the finding chart (fc) and
summed exposures are reported below:

FILTER     T_start(s)  T_stop    Exposure     Mag/3UL
=============================================================
white fc      171        321        147       > 20.85
white        3843       5478        393       > 21.06

v            4254       5890        393       > 19.63

b             585        601         15       > 18.74
b            5073       5273        196       > 20.32

u             329        579        245       > 20.12
u            4868       6384        274       > 20.20

uvw1         4664       6301        393       > 20.36

uvm2         4458       6096        393       > 20.18

uvw2         4049       5685        393       > 20.41
=================================================================

The above magnitudes are not corrected for the Galactic extinction
corresponding to a reddening of E_{B-V} = 0.05 (Schlegel et al.,
1998, ApJS, 500, 525). The photometry is on the UVOT photometric
system described in Poole et al. (2008, MNRAS, 383, 627).


GRB_name: GRB090516A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9378
SUBJECT: GRB 090516: Swift XRT refined analysis
DATE:    09/05/16 20:04:01 GMT
FROM:    Antonia Rowlinson at U.of Leicester  <bar7@star.le.ac.uk>

B. A. Rowlinson and P. Evans (U Leicester) report on behalf of the
Swift-XRT team:

We have analysed 3.0 ks of XRT data for GRB 090516 (Rowlinson et al. GCN
Circ. 9374), from 170 s to 6.4 ks after the BAT trigger. The data
comprise 327 s in Windowed Timing (WT) mode with the remainder in Photon
Counting (PC) mode. The enhanced XRT position for this burst was given
by Beardmore et al. (GCN. Circ 9376).

The light curve can be modelled with a power-law decay with two flares
superimposed on it. The initial decay index is alpha=3.27 (+0.11,
-0.10). At T+601 (+138, -52) s the decay flattens to an alpha of 0.93
(+0.11, -0.10).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.09 (+/-0.04). The
best-fitting absorption column is 1.57 (+0.10, -0.09) x 10^21 cm^-2, in
excess of the Galactic value of 4.5 x 10^20 cm^-2 (Kalberla et al.
2005). The PC mode spectrum has a photon index of 2.09 (+0.13, -0.12)
and a best-fitting absorption column of 9.6 (+2.6, -2.5) x 10^20 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 3.6 x 10^-11 (4.8 x 10^-11) erg cm^-2
count^-1.

If the light curve continues to decay with a power-law decay index of
0.93, the count rate at T+24 hours will be 0.03 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x
10^-12 (1.4 x 10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00352190.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090516A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9379
SUBJECT: GRB 090516: NOT optical observations
DATE:    09/05/16 22:47:41 GMT
FROM:    Javier Gorosabel at IAA-CSIC  <jgu@iaa.es>

J. Gorosabel (IAA-CSIC), de Ugarte Postigo (ESO, Santiago), D. Montes
(UCM, Madrid), A. Klutsch (UCM, Madrid), A.J. Castro-Tirado (IAA-CSIC),
report on behalf of a larger collaboration:

 We observed the optical afterglow of GRB 090516 (Guidorzi et al. GCN
9375) with the 2.5m NOT(+STANCAM) telescope.  On May 16.889 UT (12.9
hours post GRB) the afterglow shows an R-band magnitude of R=21.3+/-0.1
against USNO-B1.0 field stars.


GRB_name: GRB090516A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9380
SUBJECT: GRB 090516 - Zadko Telescope observations
DATE:    09/05/17 02:14:33 GMT
FROM:    David Coward at U of Western Aus.  <coward@physics.uwa.edu.au>

SUBJECT: GRB 090516 - Zadko Telescope observations
FROM: D.M Coward at UWA


T.P. Vaalsta, Liang Yan, and J. Zadko report on
behalf of the Zadko Telescope Team.

T.P. Vaalsta, Liang Yan, J. Zadko, H. Miao,
J. Moore, K. Frost, D. Coward, A. Imerito, D. Blair,
R. Burman, P. Luckas, S. Gordon, A. Fletcher,
A. Ahmet, (University of Western Australia)
M. Todd, M. Zadnik (Curtin University)
M. Boer, A. Klotz (TAROT)

The 1.0m F/4 Zadko telescope started imaging
the field of GRB 090516 (trigger=352190, D. Palmer
et al., GCN 9374) 275 minutes after the Swift
trigger. A fading source was found within the
XRT error circle (GCN 9376). The field was
observed for 131 minutes.

Preliminary photometry of unfiltered images
taken with an iKon DW436BV camera show the
following initial magnitudes of the optical
afterglow:


tmid(m) Exp. Time    Magnitude
-------------------------------------
275            5s    18.9  +/- 0.5
285           20s    19.5  +/- 0.3
296          200s    20.26 +/- 0.14


Dr David Coward
Senior Research Fellow
School of Physics
University of Western Australia
Crawley WA 6009

Tel: +61 8 6488 4563
Mobile 0423981240
Fax: +61 8 6488 1170


GRB_name: GRB090516A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9381
SUBJECT: GRB 090516: VLT redshift
DATE:    09/05/17 02:47:56 GMT
FROM:    Antonio Deugarte at IAA-CSIC  <deugarte@iaa.es>
 
A. de Ugarte Postigo (ESO), J. Gorosabel (IAA/CSIC), D. Malesani,
J.P.U. Fynbo (DARK/NBI), A. J. Levan (Univ. Warwick), report on
behalf of a larger collaboration:
 
We observed the optical afterglow of GRB 090516 (Rowlinson et al.,
GCN 9374; Guidorzi et al., GCN 9375) with the ESO VLT equipped
with FORS2. Observations started on 2009 May 16.989 UT (15.1 hr
after the GRB). In the acquisition image, the afterglow is well detected
with R ~ 21.2, consistent with the NOT measurement (Gorosabel et al.,
GCN 9379).
 
Two spectra lasting 30 min each were acquired with the grism 300V,
covering the wavelength range 3500-9200 AA. In a preliminary analysis
we detect the Lyman limit, a strong Ly-alpha absorption as well as
a number of strong absorption lines (SII, OI, CII, SiIV, CIV, AlII etc.)
at a redshift of z=3.9.
 
We acknowledge excellent support from the observing staff in Paranal, 
in particular Alain Smette, Leo Rivas and Gianni Marconi.


GRB_name: GRB090516A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9382
SUBJECT: GRB 090516: GROND OBSERVATIONS
DATE:    09/05/17 05:00:40 GMT
FROM:    Andrea Rossi at TLS Tautenburg  <rossi@tls-tautenburg.de>

A. Rossi (Tautenburg), P. Afonso and J.Greiner (both MPE Garching)
report on behalf of the GROND team:

We observed the field of GRB 090516 (Swift trigger 352190, B. Rowlinson et
al.,GCN #9374) simultaneously in g'r'i'z'JHK with GROND mounted at the 2.2m
ESO/MPI telescope at La Silla Observatory (Chile). Observations started on
16 May 2009 at 23:04 UT, 14.6 h after the burst.

We detect the afterglow at a position consistent with the enhanced
XRT error circle (A. Beardmore et al., GCN #9376) and NOT (J. Gorosabel et al.,
 GCN #9379) and Faulkes Telescope detections (C. Guidorzi et al., GCN #9375).
With an exposure time of 20min in JHK and 25min in griz, preliminary photometry
 yields the following AB magnitudes:
 
g =23.60 +-0.1
r =21.44 +-0.1
i =20.38 +-0.1
z =19.95 +-0.1
J =19.6  +-0.1
H =19.2  +-0.1
K =19.1  +-0.2

The quoted error is statistical only. There is an additional systematic
error in the absolute calibration using the GROND zero points and 2MASS
field stars which is expected to be in the 0.2 mag range. Quoted magnitudes
are not corrected for the galactic foreground extinction corresponding to a 
reddening of E_(B-V)=0.05.

Preliminary results fitting the SED with Hyperz give for no reddening a z ~ 4.5
 and for best fitting solution a photometric redshift of 4.1 +- 0.3, with 
 SMC reddening of A_v = 0.4. This SMC photometric redshift is compatible 
 with VLT's spectroscpic redshift of z = 3.9 (A. de Ugarte Postigo et al. 
 GCN #9381).


GRB_name: GRB090516A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9383
SUBJECT: GRB 090516: VLT spectrum (correction & update)
DATE:    09/05/17 08:38:02 GMT
FROM:    Antonio Deugarte at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (ESO), J. Gorosabel (IAA/CSIC), D. Malesani,
J.P.U. Fynbo (DARK/NBI), A. J. Levan (Univ. Warwick), report on
behalf of a larger collaboration:

We have reanalysed the spectrum of the afterglow of GRB 090516
(Rowlinson et al., GCN 9374; Guidorzi et al., GCN 9375) obtained
with the ESO VLT (de Ugarte Postigo et al. GCN 9381). Due to an
error in the preliminary reduction, the wavelength calibration had an
offset that has been now corrected.

In our new analysis we detect a strong Ly-alpha absorption
together with absorption lines of NV, SII, SiII, NiII, CI, SiIV, CIV,
FeII, AlII, AlIII as well as SiII* at a redshift of 4.109+/-0.002,
which we identify as the redshift of the afterglow. This is in
agreement with the photometric redshift obtained with GROND (Rossi
et al. GCN 9382).

The spectrum also shows an intervening system at z=2.697+/-0.002,
characterised by the presence of several FeII absorption lines.

[GCN OPS NOTE(17may09): Per author's request, the Subject line
was changed from "091516" to "090516". And in the first sentence
from "090416" to "090516".]


GRB_name: GRB090516A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9384
SUBJECT: GRB 090516: Swift-BAT refined analysis
DATE:    09/05/17 16:59:56 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), B. A. Rowlinson (U Leicester),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-240 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 090516 (trigger #352190)
(Rowlings, et al., GCN Circ. 9374).  The BAT ground-calculated position is
RA, Dec = 138.246, -11.848 deg, which is 
   RA(J2000)  =  09h 12m 59.1s 
   Dec(J2000) = -11d 50' 51.4" 
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 9%.
 
The mask-weighted light curve shows several overlapping peaks starting
at ~T-20 sec witht he last peak at ~T+180 sec, and then decaying
to background at ~T+330 sec. The burst went out of the BAT FOV at T+700 sec
when Swift did a pre-programmed slew.
T90 (15-350 keV) is 210 +- 65 sec (estimated error including systematics).
 
The time-averaged spectrum from T-15.5 to T+288.5 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.84 +- 0.11.  The fluence in the 15-150 keV band is 9.0 +- 0.6 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+7.98 sec in the 15-150 keV band
is 1.6 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/352190/BA/

[GCN OPS NOTE(17may09): Per author's request, the TBDs in the first sentence
in the third paragraph were replaced with the actual times.]


GRB_name: GRB090515A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9385
SUBJECT: GRB 090515: Swift/BAT spectral lag results
DATE:    09/05/17 19:35:45 GMT
FROM:    Tilan Ukwatta at GSFC/GWU  <tilan.ukwatta@gmail.com>

T. N. Ukwatta (GWU/GSFC), J. Norris (U. Denver), N. Gehrels (GSFC),
S. D. Barthelmy (GSFC) (for the Swift-BAT team):

For GRB 090515 (Beardmore et al. GCN 9356), the BAT team has analyzed
spectral lags for the data from T-0.05 sec to T+0.1 sec using non-mask
weighted light curves with 1 msec time binning. The spectral lags
were measured between standard canonical BAT energy bands: channel 1
(15-25 keV), 2 (25-50 keV), 3 (50-100 keV) and 4 (100-350 keV) are
given below.

Lag Ch3-Ch1 : 3.9 (+2.4, -2.1) msec
Lag Ch3-Ch2 : 3.0 (+1.0, -1.0) msec
Lag Ch4-Ch2 : 2.8 (+1.1, -1.4) msec
Lag Ch4-Ch3 : 1.0 (+1.0, -1.0) msec

Furthermore, Bayesian block analysis, on the light curve time range
from T+10 sec to T+230, yields that there is no apparent
extended emission for this burst.


GRB_name: GRB090518A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9386
SUBJECT: GRB 090518: Swift detection of a burst
DATE:    09/05/18 02:09:07 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

P. A. Evans (U Leicester), S. D. Barthelmy (GSFC),
D. N. Burrows (PSU), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester), D. M. Palmer (LANL),
A. Rowlinson (U Leicester), M. H. Siegel (PSU),
T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU) report on behalf of the
Swift Team:

At 01:54:44 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090518 (trigger=352420).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 119.933, +0.768 which is 
   RA(J2000) = 07h 59m 44s
   Dec(J2000) = +00d 46' 04"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a single peak
with a duration of about 5 sec.  The peak count rate
was ~4000 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 01:55:57.8 UT, 73.5 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source located at RA, Dec 119.95519, 0.75892 which
is equivalent to:
   RA(J2000)  = 07h 59m 49.25s
   Dec(J2000) = +00d 45' 32.1"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 86 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (4.65e+20
cm^-2, Kalberla et al. 2005), with an excess column of 4.9
(+3.56/-2.94) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 77 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers none of
the XRT error circle. The 8'x8' region for the list of sources generated
on-board covers 100% of the XRT error circle. The list of sources is typically
complete to about 18 mag. No correction has been made for the expected
extinction corresponding to E(B-V) of 0.04. 

Burst Advocate for this burst is P. A. Evans (pae9 AT star.le.ac.uk). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090518A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9387
SUBJECT: GRB 090518: Enhanced Swift-XRT position
DATE:    09/05/18 08:33:11 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 3965 s of XRT Photon Counting mode data and 8 UVOT
images for GRB 090518, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 119.95404, +0.75921 which is equivalent
to:

RA (J2000): 07h 59m 48.97s
Dec (J2000): +00d 45' 33.2"

with an uncertainty of 1.6 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, arXiv:0812.3662).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB090518A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9388
SUBJECT: GRB 090518: Swift-XRT refined analysis
DATE:    09/05/18 09:44:36 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

P. A. Evans (U Leicester) reports on behalf of the Swift-XRT team:

We have analysed 6.4 ks of XRT data for GRB 090518 (Evans et al. GCN 
Circ. 9386), from 88 s to 13.0 ks after the BAT trigger. The data are 
entirely in Photon Counting (PC) mode. The enhanced XRT position for 
this burst was given by Evans et al. (GCN. Circ 9387).

The light curve can be modelled with a series of power-law decays. The 
initial decay index is alpha=1.5 (+0.4, -0.3). At T+332 s the decay 
flattens to an alpha of 0.29 (+0.16, -0.38) before breaking again at 
T+2743 s to a final decay with index alpha=1.1 (+/-0.3).

A spectrum formed from the PC mode data can be fitted with an absorbed 
power-law with a photon spectral index of 2.1 (+/-0.4). The best-fitting 
absorption column is 6.2 (+2.3, -1.9) x 10^21 cm^-2, in excess of the 
Galactic value of 4.6 x 10^20 cm^-2 (Kalberla et al. 2005). The counts 
to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from 
this spectrum is 4.9 x 10^-11 (9.9 x 10^-11) erg cm^-2 count^-1.

If the light curve continues to decay with a power-law decay index of 
1.1, the count rate at T+24 hours will be 0.0031 count s^-1, 
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.5 x 
10^-13 (3.1 x 10^-13) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at 
http://www.swift.ac.uk/xrt_products/00352420.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090518A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9389
SUBJECT: GRB090518 : Optical upper limit by MOA-II telescope
DATE:    09/05/18 12:03:46 GMT
FROM:    Takashi Sako at Nagoya U./MOA  <sako@stelab.nagoya-u.ac.jp>

T. Sako, A. Fukui, K. Nishimoto (STE Lab, Nagoya Univ.)
on behalf of the MOA Collabration  report:

We searched for an optical afterglow of GRB090518 (GCN 9386, Evans et al.;
GCN 9387, Evans et al.) starting from 7:02:10 UT (5 hours after the burst)
with the MOA-II 1.8m telescope at Mt.John observatory in New Zealand.
In a single image of a 300sec exposure with a wideband Red filter (center 
wavelength ~ 750nm and FWHM ~ 250nm), we did not find any object
within the error circle of the Swift XRT source position (GCN 9387).
A 5 sigma upper limit is set in the I magnitude at 18.9 mag.   
This photometry was done by using the DoPhoto and calibrated against the 
USNO-B1.0 catalog stars, and not corrected for the Galactic extinction.


GRB_name: GRB090513A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9390
SUBJECT: GRB090513: Fermi GBM detection
DATE:    09/05/18 12:06:28 GMT
FROM:    Colleen A. Wilson at NASA/MSFC/NSSTC  <colleen.wilson@nasa.gov>

Colleen A. Wilson-Hodge (NASA/MSFC)
reports on behalf of the Fermi GBM Team:

"At 21:58:47.92 UT on 13 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090513 (trigger 263944729 / 090513.916).

The on-ground calculated location, using the GBM trigger
data, is RA = 269.8, DEC = -31.6 (J2000 degrees,
equivalent to 17 h 59 m, -31 d 36'), with an uncertainty
of 4.6 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 89 degrees.

The GBM light curve shows a broad peak
with a duration (T90) of about 23 s (8-1000 keV).
The time-averaged spectrum from T0-1 s to T0+19 s is
adequately fit by a power law function with an exponential
high energy cutoff.  The power law index is -0.9 +/- 0.1 and
the cutoff energy, parameterized as Epeak, is 850 +/- 390 keV

The event fluence (8-1000 keV) in this time interval is
(6.8 +/- 0.4)E-06 erg/cm^2. The 1 s peak photon flux measured
starting from T0+5.1 s in the 8-1000 keV band
is 2.7 +/- 0.2 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090516A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9391
SUBJECT: GRB 090516, RIMOTS optical upper limits
DATE:    09/05/18 13:29:42 GMT
FROM:    Norisuke Ohmori at Miyazaki U  <ohmori@astro.miyazaki-u.ac.jp>

N. Ohmori, E. Sonoda, K. Kono, H. hayasi,
A. Daikyuji, Y. Nisioka, K. Noda, M. Yamauchi
(University of Miyazaki)

We have observed the field covering the error circle of
GRB090516 (Swift trigger 352190, GCN 9374, Rowlinson et al.)
with the unfiltered CCD camera on the 30-cm telescope
at University of Miyazaki.
The observation was started 11:16:08 UT (1.8 hr after the Swift trigger),
under cloudy condition.
First image was obtained at 11:17:11 UT (1.8 hr after the Swift trigger).

We have compared our data of 30 sec exposures with the USNO-A2.0 catalog.
There is no new source at the reported position.
(GCN 9374, B. A. Rowlinson et al. GCN 9375, C. Guidorzi et al. 
 GCN 9376, A. P. Beardmore et al. GCN 9379, J. Gorosabel et al. 
 GCN 9381, A. de Ugarte Postigo et al.)

the upper limits are as follows:
---------------------------------------------------------------
Start(UT)  End(UT) Num. of frames Limit (mag.)
---------------------------------------------------------------
11:16:08   11:17:11         1         15.6
11:16:08   12:04:00        21         17.7
---------------------------------------------------------------


GRB_name: GRB090518B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9392
SUBJECT: GRB 090518B: Fermi GBM detection
DATE:    09/05/18 14:45:29 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: 

"At 05:51:04.67 UT on 18 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090518B (trigger 264318666 / 090518244).
The on-ground calculated location, using the GBM trigger 
data, is RA = 211.2, DEC = -16.7 (J2000 degrees, 
equivalent to 14h 05m, -16d 42'), with an uncertainty 
of 4.5 degrees (radius, 1-sigma containment, 
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 90 degrees.

The GBM light curve shows one structured peak
with a duration (T90) of about 12 s (8-1000 keV). 
The time-averaged spectrum from T0-0.768 s to T0+6.656 s is 
well fit by a power law function with an exponential
high energy cutoff.  The power law index is -0.74 +/- 0.13 and
the cutoff energy, parameterized as Epeak, is 127 +/- 12 keV
(chi squared 399 for 363 d.o.f.).

The event fluence (8-1000 keV) in this time interval is 
(2.2 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured 
starting from T0-0.256 s in the 8-1000 keV band 
is 5.6 +/- 0.6 ph/s/cm^2.

The spectrum can also be fit by using a Band function with 
Epeak = 86 +/- 15 keV and beta = -2.10 +/- 0.14. However alpha 
is poorly constrained.

The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090518A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9393
SUBJECT: GRB 090518, Swift-BAT refined analysis
DATE:    09/05/18 15:29:11 GMT
FROM:    Takanori Sakamoto at NASA/GSFC  <takanori.sakamoto-1@nasa.gov>

J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), 
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), 
C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), A. M. Parsons (GSFC),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-119 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090518 (trigger #352420)
(Evans, et al., GCN Circ. 9386).  The BAT ground-calculated position is
RA, Dec = 119.957, 0.778 deg which is 
   RA(J2000)  =  07h 59m 49.6s 
   Dec(J2000) = +00d 46' 41.4" 
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 75%.
 
The mask-weighted light curve shows a FRED-like peak starting at T-0.5 sec, 
peaking at T+0 sec, and ending at T+3 sec.  T90 (15-350 keV) is 
6.9 +- 1.7 sec (estimated error including systematics).
 
The time-averaged spectrum from T-2.4 to T+6.9 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.54 +- 0.14.  The fluence in the 15-150 keV band is 4.7 +- 0.4 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T-0.08 sec in the 15-150 keV band
is 2.4 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/352420/BA/


GRB_name: GRB090518A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9394
SUBJECT: GRB 090518: P60 Observations
DATE:    09/05/18 21:51:50 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko@srl.caltech.edu>

S. B. Cenko (UC Berkeley) reports on behalf of a larger collaboration:

We have imaged the field of GRB090518 (Evans et al., GCN 9386) with the
automated Palomar 60-inch telescope beginning at 3:45 UT on 2009 May 18 (~
1.83 hr after the burst).  Observations were taken in the r', i', and z'
filters at high airmass.  We find no sources inside the enhanced XRT
error circle (Evans et al., GCN 9387), to the following limiting
magnitudes:

Filter     Magnitude
--------------------------------
r'         > 20.5
i'         > 20.0
z'         > 19.0

No correction has been applied for Galactic extinction along the line of
sight.


GRB_name: GRB090518A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9395
SUBJECT: GRB090518: GROND upper limits
DATE:    09/05/19 02:37:52 GMT
FROM:    Andrea Rossi at TLS Tautenburg  <rossi@tls-tautenburg.de>

A. Rossi (Tautenburg), P. Afonso and J. Greiner( both MPE Garching) report
on behalf of the GROND team:

GROND (Greiner et al. 2008, PASP 120, 405), mounted at the 2.2m ESO/MPI
telescope at La Silla Observatory (Chile), observed the field of GRB 090518
(P. Evans et al. 2009, GCN #9386) simultaneously in the g'r'i'z'JHK
bands. Observations started on May 18, at 23:01 UTC, 21.1 h after the burst.
In stacked images of 49 min total integration time in griz and 40 min in
JHK, we do not detect any new object inside the enhanced XRT error circle
(P. Evans et al., GCN #9387), down to the following limiting magnitudes
(all in the AB system):

g' > 24.5
r' > 24.9
i' > 24.2
z' > 23.8
J  > 22.4
H  > 22.1
K  > 21.2

The upper limits have been obtained using GROND zero points and 2MASS
field stars as reference. No correction has been made for the expected
extinction corresponding to E(B-V) of 0.04 mag.


GRB_name: GRB090516A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9396
SUBJECT: GRB 090516: Observations from Stardome Observatory
DATE:    09/05/19 06:10:37 GMT
FROM:    Antonio Deugarte at IAA-CSIC  <deugarte@iaa.es>

G. W. Christie (Stardome, New Zealand), A. de Ugarte Postigo
(ESO, Chile) and  T. Natusch (Stardome, New Zealand) on
behalf of a larger collaboration report:

We observed the field of GRB 090516 (Rowlinson et al. GCN
9374) with the Stardome 0.4m telescope located in Auckland
(New Zealand) starting at 09:25UT. We used a SG530 filter
that transmits wavelengths above 5300 Angstroms and a SBIG
ST-L-6303E CCD (KAF-6303E detector). A 9x300s combined
exposure with mean epoch 16.4080 May (80 minutes after the
burst) shows an object at the position of the afterglow
(Guidorzi et al. GCN 9375) measured at R = 20.8 +/- 0.2 as
compared to USNO-B1.0 stars.  We note that with the GRB at
a redshift of 4.1 (de Ugarte Postigo et al. GCN 9383),
Ly-alpha falls within the R-band, so that comparison of
clear and very broad band filters such as ours with R-band
has to be handled with care.


GRB_name: GRB090518A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9397
SUBJECT: GRB 090518: Swift/UVOT Upper Limits
DATE:    09/05/19 11:50:39 GMT
FROM:    Frank Marshall at GSFC  <marshall@milkyway.gsfc.nasa.gov>

F.E. Marshall (NASA/GSFC) and P. Evans (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT observed the field of GRB 090518 starting 77 s after
the BAT trigger (Evans et al., GCN Circ. 9386). No optical afterglow
is detected in the initial UVOT exposures at the position
of the X-ray afterglow (Evans et al., GCN Circ. 9387).
Three-sigma upper limits using the UVOT photometric system
(Poole et al. 2008, MNRAS, 383, 627) for the first finding chart (FC)
exposure and subsequent exposures are:

Filter          T_start(s)   T_stop(s)      Exp(s)        Mag 

white (FC)          77          227          147         >20.7
white               77         1367          373         >21.3
v                  620         1417           97         >19.3
b                  545         1341           78         >19.7
u                  290         1316          304         >20.0
uvw1               669         1466           97         >19.7
uvm2               644         1442           97         >21.2
uvw2               596         1392           97         >20.0

The values quoted above are not corrected for the Galactic extinction due
to the reddening of E(B-V) = 0.04 in the direction of the burst 
(Schlegel et al. 1998).


GRB_name: GRB090514A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9398
SUBJECT: GRB 090514: Fermi GBM detection
DATE:    09/05/19 13:59:08 GMT
FROM:    Colleen A. Wilson at NASA/MSFC/NSSTC  <colleen.wilson@nasa.gov>

Colleen A. Wilson-Hodge (NASA/MSFC)
reports on behalf of the Fermi GBM Team:

"At 00:08:39.16 UT on 14 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090514 (trigger 263952521 / 090514006).

The on-ground calculated location, using the GBM trigger
data, is RA = 12.3, DEC = -10.9 (J2000 degrees,
equivalent to 0 h 49 m, -10 d 54'), with an uncertainty
of 4.6 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 19 degrees.

The GBM light curve consists of multiple peaks
with a duration (T90) of about 49 s (8-1000 keV).
The time-averaged spectrum from T0-1.5 s to T0+56.8 s is
adequately fit by a simple power law function with index -1.92 +/- 0.04.

The event fluence (8-1000 keV) in this time interval is
(8.1 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.256 s in the 8-1000 keV band
is 7.6 +/- 0.2 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090511A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9399
SUBJECT: GRB 090511: Fermi GBM Detection
DATE:    09/05/19 20:48:51 GMT
FROM:    Valerie Connaughton at MSFC  <valerie@nasa.gov>

Valerie Connaughton (UAH) reports on behalf of the Fermi GBM Team:

"At 16:25:16.37 UT on 11 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090511 (trigger 263751918 / 090511684).

The on-ground calculated location, using the GBM trigger
data, is RA = 161.9, DEC = 51.3 (J2000 degrees,
equivalent to 10 h 48 m, 51 d 18 '), with an uncertainty
of 7.0 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).

The angle from the Fermi LAT boresight is 67 degrees.

The GBM light curve consists of a single pulse
with a duration (T90) of about 14 s (8-1000 keV).
The time-averaged spectrum from T0-5.1 s to T0+4.1 s is
best fit by a power law function with an exponential
high energy cutoff.  The power law index is -0.95 +/- 0.18 and
the cutoff energy, parameterized as Epeak, is 391 +/- 157 keV.

The event fluence (8-1000 keV) in this time interval is
(1.8 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1 s in the 8-1000 keV band
is 2.5 +/- 0.4 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090519A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9400
SUBJECT: GRB 090519: Swift detection of a burst
DATE:    09/05/19 21:22:46 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

M. Perri (ASDC), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),
C. Gronwall (PSU), S. T. Holland (CRESST/USRA/GSFC),
J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC),
P. T. O'Brien (U Leicester), C. Pagani (PSU), D. M. Palmer (LANL),
A. Rowlinson (U Leicester), M. H. Siegel (PSU),
M. Stamatikos (NASA/ORAU) and T. N. Ukwatta (GSFC/GWU) report on
behalf of the Swift Team:

At 21:08:56 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090519 (trigger=352648).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 142.293, +0.183 which is 
   RA(J2000)  =  09h 29m 10s
   Dec(J2000) = +00d 10' 58"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows several overlapping peaks
with a duration of about 40 sec.  The peak count rate
was ~1300 counts/sec (15-350 keV), at ~3 sec after the trigger. 

The XRT began observing the field at 21:10:51.3 UT, 114.9 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 142.27902, 0.17925 which
is equivalent to:
   RA(J2000)  = 09h 29m 6.96s
   Dec(J2000) = +00d 10' 45.3"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 52 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (2.96e+20
cm^-2, Kalberla et al. 2005), with an excess column of 1.9
(+2.14/-1.86) x 10^21 cm^-2 (90% confidence). 

The initial flux in the 2.5 s image was 5.77e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 123 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.04. 

Burst Advocate for this burst is M. Perri (perri AT asdc.asi.it). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090519A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9401
SUBJECT: GRB 090519: TAROT Calern observatory optical observations
DATE:    09/05/19 21:51:16 GMT
FROM:    Alain Klotz at CESR-CNRS  <Alain.Klotz@free.fr>

Klotz, A. (CESR-OMP), Gendre, B. (LAM-OAMP),
Boer M. (OHP-OAMP), Atteia J.L. (LATT-OMP) report:

We imaged the field of GRB 090519 detected by SWIFT
(trigger 352648) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.

The observations started 76.0s after the GRB trigger
(6.6s after the notice). The elevation of the field decreased from
21 degrees above horizon and weather conditions
were good.

The date of trigger : t0 = 2009-05-19T21:08:56.5

The first image is trailed with a duration of 60.0s
(see the description in Klotz et al., 2006, A&A 451, L39).
We do not detect any OT at the XRT position mentionned
by Perri et al. 2009 (GCNC 9400) with a limiting magnitude of:
t0+76.0s to t0+136.0s : R > 16.8

The second image is 30.0s exposure in tracking mode:
t0+142.8s to t0+172.8s : R > 17.5

We co-added a series of exposures:
t0+142.8s to t0+319.6s : R > 18.5

Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.

N.B. Galactic coordinates are lon=233.3028 lat=+34.5244
and the galactic extinction in R band is 0.1 magnitude
estimated from D. Schlegel et al. 1998ApJ...500..525S.

This message may be cited.


GRB_name: GRB090519A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9402
SUBJECT: GRB 090519: FARO Chante Perdrix Observatory optical observations
DATE:    09/05/19 22:13:56 GMT
FROM:    Alain Klotz at CESR-CNRS  <Alain.Klotz@free.fr>

Klotz, A. (CESR-OMP), Kugel, F. (Obs. Chanteperdrix) report:

We imaged the field of GRB 090519 detected by SWIFT
(trigger 352648) with the FARO robotic telescope (D=20cm)
located at the Chante Perdrix Observatory, Banon, France.
FARO stands for Francois & Alain Robotic Observatory:
http://chanteperdrix.dyndns.org

The observations started 122.4s after the GRB trigger
(53.0s after the notice). The elevation of the field decreased
from 22 degrees above horizon and weather conditions
were good.

The date of trigger : t0 = 2009-05-19T21:08:56.5

The first image is 60.0s exposure in tracking mode.
We do not detect any OT at the XRT position mentionned
by Perri et al. 2009 (GCNC 9400) with a limiting magnitude of:
t0+122.4s to t0+182.4s : R > 15.7

Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.

This message may be cited.


GRB_name: GRB090519A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9403
SUBJECT: GRB 090519: NOT afterglow candidate
DATE:    09/05/19 22:32:39 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@astro.ku.dk>

C.C. Thoene (INAF/Brera), D. Malesani (DARK/NBI), A.J. Levan (Univ. 
Warwick), P. Jakobsson (Univ. Iceland), J. Hjorth (DARK/NBI), N.R. 
Tanvir (Univ. Leicerster), report on behalf of a larger collaboration

We observed the field of GRB 090519 (Perri et al., GCN 9400) with the 
NOT equipped with ALFOSC.

At the edge of the XRT error circle, we detect a fading source at 
coordinates (J2000):

RA = 09:29:07.0
Dec = +00:10:49.1

with an error of ~0.5". The source faded by ~0.3 +- 0.10 mag between 
19.8 and 44.4 min after the GRB, suggesting that this is indeed the 
afterglow of GRB 090519. A (fainter) object is seen at the position of 
the candidate in the SDSS, which may be a bright host galaxy. On May 
19.897 UT, the source had R ~ 21.6.


GRB_name: GRB090519A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9404
SUBJECT: GRB 090519: Limits from BOOTES-1B
DATE:    09/05/19 23:59:23 GMT
FROM:    Martin Jelinek at Inst.Astrophys.Andalucia,Granada  <mates@iaa.es>

Martin Jelinek (IAA Granada) and Petr Kubanek (IPL Valencia) 
on behalf of the BOOTES team.

report

    We observed the errorbox of the GRB 090519 (Perri et al,
GCN9400) with the 30cm robotic telescope BOOTES-1B in Spain.
The observation  started 99s  after the GRB  trigger. In our
unfiltered images we do not detect any new object within the
BAT or XRT errorbox with the following limits:

Tstart-Tgrb  exposure  limit
99s           3.5s     15.1
108s          30s      16.5
108s         23x30s    17.6

This message may be cited


GRB_name: GRB090519A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9405
SUBJECT: GRB 090519: Enhanced Swift-XRT position
DATE:    09/05/20 01:25:47 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 2178 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 090519, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 142.27878, +0.18020 which is equivalent
to:

RA (J2000): 09h 29m 6.91s
Dec (J2000): +00d 10' 48.7"

with an uncertainty of 1.8 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, arXiv:0812.3662).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB090519A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9406
SUBJECT: GRB 090519, Swift-BAT refined analysis
DATE:    09/05/20 02:30:23 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <jayc@milkyway.gsfc.nasa.gov>

H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), 
W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), 
E. E. Fenimore (LANL), N. Gehrels (GSFC), C. B. Markwardt (GSFC/UMD), 
D. M. Palmer (LANL), A. M. Parsons (GSFC), M. Perri (ASDC), 
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), 
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-119 to T+276 sec from the recent telemetry 
downlink, we report further analysis of BAT GRB 090519 (trigger #352648)
(Perri, et al., GCN Circ. 9400).  The BAT ground-calculated position is
RA, Dec = 142.317, 0.190 deg which is
   RA(J2000)  =  09h 29m 16.2s
   Dec(J2000) = +00d 11' 23.9"
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
This is 0.8 arcmin from the enhanced XRT afterglow position (Goad et al.
GCN Circ #9405).  The partial coding was 57%.
 
The mask-weighted lightcurve shows multiple overlapping peaks starting 
at about T-17 sec and ending about T+95 sec.  T90 (15-350 keV) is 
64 +- 10 sec (estimated error including systematics).
 
The time-averaged spectrum from T-12.4 to T+60.4 sec is best fit by a 
simple power-law model.  The power law index of the time-averaged 
spectrum is 1.02 +- 0.20.  The fluence in the 15-150 keV band is 
1.2 +- 0.1 x 10-06 erg/cm2.  The 1-sec peak photon flux measured from 
T-10 sec in the 15-150 keV band is 0.6 +- 0.2 ph/cm2/sec.  All the 
quoted errors are at the 90% confidence level.
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/352648/BA/


GRB_name: GRB090519A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9407
SUBJECT: GRB 090519: Swift/UVOT Upper Limits
DATE:    09/05/20 03:27:00 GMT
FROM:    Stefan Immler at NASA/GSFC  <stefan.m.immler@nasa.gov>

S. Immler (NASA/CRESST/GSFC) and M. Perri (ASDC) report on
behalf of the Swift/UVOT team:

The Swift/UVOT observed the field of GRB 090519 starting 106 s after
the BAT trigger (Perri et al., GCN Circ. 9400). No optical afterglow
is detected in the initial UVOT exposures at the enhanced position
of the X-ray afterglow (Goad et al., GCN Circ. 9405) or the position
of the NOT afterglow candidate (Thoene et al. GCN Circ. 9403).
Three-sigma upper limits using the UVOT photometric system
(Poole et al. 2008, MNRAS, 383, 627) are:

Filter          T_start(s)   T_stop(s)      Exp(s)        Mag

white              123         7430          862         >21.5
v                  106         7841          597         >19.8
b                  536         7224          568         >20.6
u                  281         7019          617         >20.4
uvw1               662         8131          469         >20.3
uvm2               637         8046          587         >20.4
uvw2               588         7636          549         >20.6

The values quoted above are not corrected for the Galactic extinction due
to the reddening of E(B-V) = 0.04 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB090519A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9408
SUBJECT: GRB 090519: GROND observation
DATE:    09/05/20 08:02:04 GMT
FROM:    Jochen Greiner at MPI  <jcg@mpe.mpg.de>

A. Rossi (Tautenburg), T. Kruehler, J. Greiner and A. Yoldas (all MPE Garching)
report on behalf of the GROND team:

We observed the field of GRB 090519 (Swift trigger 352648, M. Perri et al.,
GCN #9400) simultaneously in g'r'i'z'JHK with GROND mounted at the 2.2m
ESO/MPI telescope at La Silla Observatory (Chile). Observations started on
19 May 2009 at 23:44 UT, 2.5 h after the burst, under challenging sky 
conditions with cirrus.

We detect the afterglow at a position consistent with the enhanced XRT error 
circle and NOT (Thoene et al., GCN #9403). With an exposure time of 40min in 
JHK and 49min in griz, preliminary photometry yields the following AB 
magnitudes:
 
g =25.0 +-0.4
r =23.5 +-0.2
i =23.5 +-0.3
z >23.6
J >21.9
H >20.7
K >19.9

calibrated using SDSS and 2MASS field stars. The quoted magnitudes are not 
corrected for the galactic foreground extinction corresponding to a 
reddening of E_(B-V)=0.04.

The large g-i color as compared to r-i indicates that the Lyman break may
be located in the g' band. Fitting the SED with Hyper-Z results in a 
preliminary photometric redshift of z = 3.9+0.4-0.7, assuming no intrinsic 
extinction. 


GRB_name: GRB090519A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9409
SUBJECT: GRB 090519: VLT spectroscopic redshift
DATE:    09/05/20 08:54:17 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>

A. J. Levan (Univ. Warwick), P. Jakobsson (U. Iceland), C. C. Thoene
(INAF/OAB), P. D'Avanzo (U.  Bicocca & INAF/OAB), A. De Cia (U. Iceland),
J. P. U. Fynbo, J. Hjorth, D. Malesani (DARK/NBI), D. Fugazza (INAF/OAB),
N. R. Tanvir (U. Leicester) report on behalf of a larger collaboration:

Using FORS2 on the ESO Very Large Telescope, we have obtained 
low-resolution spectra (3 x 30 min) of the optical afterglow of GRB 
090519 (Perri et al., GCN 9400; Thoene et al., GCN 9403) with the grism 
300V, covering the wavelength range 3500-9200 AA. In the acquisition 
image  the afterglow has a magnitude of R ~ 23.5. The first spectrum 
was  taken approximately 4 hours after the burst.

In a preliminary analysis we detect a break around 4400 AA and strong 
absorption features around 5000 AA and 5900 AA. We interpret these 
features as the Lyman limit, Lyman-beta and Lyman-alpha at a redshift of 
z = 3.85. This is in agreement with the photometric redshift reported by 
Rossi et al. (GCN 9408).

We thank the Paranal staff for excellent support, in particular Gianni 
Marconi, Kieran O'Brien and Patricia Guajardo.

[GCN OPS NOTE(20may09): Per the original first-author's (CCT) request,
the author list was changed.]


GRB_name: GRB090519A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9410
SUBJECT: GRB 090519: NOT refined analysis
DATE:    09/05/20 14:53:33 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@astro.ku.dk>

D. Malesani (DARK/NBI), C.C. Thoene (INAF/Brera), P. Jakobsson (Univ. 
Iceland), A.J. Levan (Univ. Warwick) J.P.U. Fynbo, B. Milvang-Jensen 
(DARK/NBI), report on behalf of a larger collaboration.

We provide further analysis of the photometric data on the afterglow of 
GRB 090519 (Perri et al., GCN 9400) taken at the NOT and VLT (Thoene et 
al., GCN 9403; Levan et al., GCN 9409).

Calibration of the field based on archival VLT zeropoints yields a 
significantly fainter magnitude for the afterglow with respect to our 
previous GCN 9403, which was based on USNO stars. The new calibration is 
consistent with SDSS stars and with the value reported by Rossi et al. 
(GCN 9408). We find for the afterglow R = 22.8 on 2009 May 19.897 UT 
(0.33 hr after the GRB).

The decay of the afterglow is well described by a power law with index 
alpha = 0.44 +- 0.03 between 0.33 and 3.6 hr after the GRB.


GRB_name: GRB090519A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9411
SUBJECT: GRB 090519: Swift-XRT refined analysis
DATE:    09/05/20 15:17:58 GMT
FROM:    Matteo Perri at ISAC/ASDC  <perri@asdc.asi.it>

M. Perri, V. D'Elia, G. Stratta (ASDC) report on behalf of the
Swift-XRT team:

We have analysed the first 17 ks of XRT data for GRB 090519 (Perri et al.,
GCN Circ. 9400), from 121 s to 37 ks after the BAT trigger. The first
41 seconds of data are in Windowed Timing (WT) mode and at later times
in Photon Counting (PC) mode. The enhanced XRT position for this burst
was given by Goad et al. (GCN. Circ. 9405).

The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=2.8 (+/-0.2). At around T+580 s the decay
flattens to an alpha of 0.6 (+/-0.3) before breaking again at about
T+2 ks to a final decay with index alpha=1.4 (+0.3)(-0.2).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.5 (+/-0.2). The best-fitting
intrinsic absorption column at z=3.85 (Thoene et al., GCN Circ. 9409)
is 1.9(+1.7,-1.6)e22 cm^-2, in excess of the Galactic value of
3.0e20 cm^-2 (Kalberla et al. 2005). The counts-to-observed (-unabsorbed)
0.3-10 keV flux conversion factor deduced from this spectrum is
4.9e-11 (5.4e-11) erg cm^-2 count^-1.

If the light curve continues to decay with a power-law decay index of
1.4, the count rate at T+24 hours will be 3e-4 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of
1.5e-14 (1.6e-14) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00352648.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090519B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9412
SUBJECT: GRB 090519B: Fermi GBM detection
DATE:    09/05/20 15:32:50 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: 

"At 11:05:27.54 UT on 19 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090519B (trigger 264423929 / 090519462).
The on-ground calculated location, using the GBM trigger 
data, is RA = 105.9, DEC = -56.7 (J2000 degrees, 
equivalent to 07h 04m, 56d 42'), with an uncertainty 
of 3.9 degrees (radius, 1-sigma containment, 
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 18 degrees.

The GBM light curve shows a single peak lasting 
about 4 seconds superimposed on a lower-level continuum.
The burst duration (T90) is about 87 s (8-1000 keV).
The time-averaged spectrum from T0-2.432 s to T0+1.152 s is 
well fit by a simple power law function with index -1.63 +/- 0.05 
(chi squared 822 for 720 d.o.f.).

The event fluence (8-1000 keV) in this time interval is 
(1.40 +/- 0.01)E-06 erg/cm^2. The 1-sec peak photon flux measured 
starting from T0-0.640 s in the 8-1000 keV band 
is 5.02 +/- 0.14  ph/s/cm^2.

The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090516B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9413
SUBJECT: GRB 090516B: Fermi GBM detection
DATE:    09/05/20 17:04:52 GMT
FROM:    Sheila McBreen at MPE  <smcbreen@mpe.mpg.de>

Sheila McBreen (UCD/MPE)
reports on behalf of the Fermi GBM Team:

"At 03:17:20.17 UT on 16 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090516B (trigger 264136642 / 090516137).

The on-ground calculated location, using the GBM trigger
data, is RA = 122.2, DEC = -71.62 (J2000 degrees,
equivalent to 08 h 09 m, -71 d 37 '), with an uncertainty
of 2.6 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 45 degrees.

The GBM light curve consists of several overlapping
peaks from the trigger to about 140 s and possible
weak emission out to about 350 s.

The time-averaged spectrum from T0 s to T0+138 s is
adequately fit by a power law function with an exponential
high energy cutoff.  The power law index is -1.01 (+/-0.06) and
the cutoff energy, parameterized as Epeak, is
327.0 (+/-58.7) keV (chi squared 419 for 359 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(3.0 +/- 0.1)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+80 s in the 8-1000 keV band
is 4.0 +/- 0.2 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090516A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9415
SUBJECT: GRB 090516: Fermi GBM observation
DATE:    09/05/21 08:51:16 GMT
FROM:    Sheila McBreen at MPE  <smcbreen@mpe.mpg.de>

Sheila McBreen (UCD/MPE)
reports on behalf of the Fermi GBM Team:

"At 08:27:58.35 UT on 16 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090516 (trigger 264155280 / 090516353).
which was also detected by the Swift-BAT
(Rowlinson et al. 2009, GCN 9374).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 20 degrees.

The GBM light curve consists of about five overlapping
pulses from T0-50 s to T+120 s. There is continued weak emission
until about T0+300 s (8-1000 keV).

Due to a large change in the spacecraft pointing during this long
burst, a time averaged spectrum could not be fit. Instead three
spectral intervals from -50 to 20 sec, 20 to 60 sec
and 60 to 120 seconds were selected.

The first interval was well fit by a power law function with
an exponential high energy cutoff.  The power law index
is -1.51 ( +/-0.11 ) and the cutoff energy, parameterized as
Epeak, is 185.6 (+98.4/-42.5) keV.

The second and third intervals are adequately fit by a Band function.
The parameters for interval two are alpha = -1.03 (+0.26/-0.31) ,
Epeak = 51.4 (+20.1, -11.4), beta= -2.1 ( +0.1/-0.2)
and for the third interval, alpha = 0.30 (+1.30/ - 0.78),
Epeak = 27.87 +/- 5.0), beta = -2.64 +/-0.4.

The sum of the event fluence (8-1000 keV) in these time intervals is
(2.3 +/- 0.5)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+28.6 s in the 8-1000 keV band
is 5.3 +/- 0.2 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090423A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9416
SUBJECT: GRB 090423: Fermi GBM T90 follow-up analysis results
DATE:    09/05/21 14:26:47 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

A. von Kienlin (MPE), C. Kouveliotou (NASA/MSFC) and V. Connaughton (UAH) 
report on behalf of the Fermi GBM Team:

"We performed a detailed follow-up analysis of the T90 of the high redshift 
GRB 090423 (H. Krimm et al., GCN Circ. # 9198) to determine the nature of 
the extended pulse centered at T+30s as reported earlier (A. von Kienlin, 
GCN # 9229). Due to the low significance of the detection, we were not able 
to accurately locate this later pulse (the emission was only significantly 
seen with one of the two triggered detectors). We conclude, therefore, that 
this pulse is most probably due to background fluctuations.

The final GBM T90 derived between 10-300 keV is 11.5 +/- 2.0 sec. This 
duration agrees within the error with the value of 10.3 +/- 1.1 sec reported

by the Swift team (H. Krimm et al., GCN Report 211.2)"


GRB_name: GRB090520A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9417
SUBJECT: GRB 090520 Swift-BAT detection of a burst in ground analysis
DATE:    09/05/21 21:04:47 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <jayc@milkyway.gsfc.nasa.gov>

J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), E. E. Fenimore (LANL),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL),
A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC),
M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):

On May 20, 2009 at 01:37:16 UT, BAT triggered on GRB 090520
(trigger #352671).  The burst was weak, and the instrument 
failed to find a source in onboard analysis.  A significant 
source was found in ground analysis.  The source is located at 
RA, Dec 11.613, -8.000 deg, which is

   RA(J2000)  =  00h 46m 27.1s
   Dec(J2000) = -08d 00' 00"
with an uncertainty of 3 arcmin (radius, sys+stat, 90% 
containment). The partial coding was 48%.

The burst consisted of a single FRED pulse, starting about
T-2 seconds, with a T90 of 20  5 seconds (estimated error 
including systematics).

The BAT event data for failed triggers is limited to 10 seconds.  
Using 10 seconds of event data from T-2 to T+8 seconds, the
best fit to the spectrum is a simple powerlaw with a photon
index of 0.8 +- 0.2.  The fluence for this interval in the
15-150 keV band was 3.4  0.5 x 10-7 ergs/cm2 
(68% confidence).

The BAT source position was about 3 arcmin from a low-redshift
galaxy, 6dFGS gJ004613.4-080000.  This is an emission-line 
galaxy at z = 0.0850.

A Swift TOO was requested, but initially the source was in the
Swift Moon constraint.  In any case was 52 degrees (~2.5 hours 
in RA) from the Sun, not in constraint, but still an unfavorable 
angle, so no Swift followup observation is planned.


GRB_name: GRB090516C
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9418
SUBJECT: GRB 090516C: Fermi GBM detection
DATE:    09/05/21 23:32:21 GMT
FROM:    Alexander van der Horst at NASA/MSFC  <Alexander.J.VanDerHorst@nasa.gov>

A.J. van der Horst (NASA/MSFC/ORAU) reports on behalf of the
Fermi GBM Team:

"At 20:28:40.05 UT on 16 May 2009, the Fermi Gamma-ray Burst Monitor
(GBM) triggered and located GRB 090516C (trigger 264198522 / 090516.853).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 15.7, Dec = -13.7 (J2000 degrees, equivalent to
J2000 1h03m, -13d41'), with a statistical uncertainty of 3.5 degrees
(radius, 1-sigma containment, statistical only; there is additionally
a systematic error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 69 degrees.

The GBM light curve consists of one short spike and some smaller peaks,
with a total duration (T90) of 15 s (8-1000 keV). The time-averaged
spectrum from T0+0.00 to T0+15.26 s is adequately fit by a power law
with an exponential high-energy cutoff. The index is -1.51 +/- 0.08
and the cutoff energy, parameterized as Epeak, is 210 +/- 68 keV
(chi squared 372 for 360 d.o.f.). The Band function provides a
significantly better fit (chi squared 365 for 359 d.o.f.) with a lower
Epeak value, but the low-energy index alpha and the amplitude are
poorly constrained: alpha is -0.44 +/- 0.81, beta is -1.81 +/- 0.06,
and Epeak is 38 +/- 14.
The fluence (8-1000 keV) in this interval is (4.0 +/- 0.3)E-6 erg/cm^2.
The 1-sec peak photon flux measured starting from T0+0.0s in the
8-1000 keV band is 7.7 +/- 0.4 ph/s/cm^2.

The spectral and temporal analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090518A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9419
SUBJECT: GRB 090518: Fermi GBM detection
DATE:    09/05/22 16:29:30 GMT
FROM:    Bill Paciesas at UAH  <bill.paciesas@nasa.gov>

W. Paciesas (UAH) reports on behalf of the Fermi GBM Team:

"At 01:54:44.52 UT on 18 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090518 (trigger 264304486 / 090518080).
which was also detected by the SWIFT-BAT
(Evans et al. 2009, GCN 9386)
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 53 degrees.

The GBM light curve consists of a single asymmetric peak
with a duration (T90) of about 9 s (8-1000 keV).
The time-averaged spectrum from T0-2.048 s to T0+7.04 s is
adequately fit by a simple power law function with index -1.59 +/- 0.06
(chi squared 688 for 688 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(1.60 +/- 0.05)E-6 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.64 s in the 8-1000 keV band
is 4.7 +/- 0.1 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090520A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9420
SUBJECT: GRB 090520: GROND upper limits
DATE:    09/05/22 23:53:35 GMT
FROM:    Andrea Rossi at TLS Tautenburg  <rossi@tls-tautenburg.de>

A. Rossi (Tautenburg), T. Kruehler and J. Greiner (both MPE Garching) 
report on behalf of the GROND team:

GROND (Greiner et al. 2008, PASP 120, 405) at the 2.2m ESO/MPI telescope at La
 Silla Observatory (Chile) 
started follow-up observations of GRB 090520 (Cummings et al. 2009, GCN #9417)
 on May 21, at 09:35 UTC 
(~32 h after the burst). In addition, a second epoch of imaging was obtained,
 which started on May 22, 09:37 UTC.

Image subtraction does not reveal any variable source between the two epochs. 
The first epoch thus yields the following upper limits:

g > 23.8
r > 24.0
i > 23.4
z > 23.2
J > 21.8
H > 21.4
K > 20.8

obtained using the GROND zeropoints and 2MASS field stars as reference.


GRB_name: GRB090513B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9421
SUBJECT: GRB 090513B: Fermi GBM detection
DATE:    09/05/23 22:06:17 GMT
FROM:    Vandiver Chaplin at UAH/Fermi-GBM  <chapliv@email.uah.edu>

V. Chaplin (UAH) reports on behalf of the Fermi GBM Team:

"At 22:35:35.34 UT on 13 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located the weak GRB 090513B (trigger 263946937 / 090513941).
The on-ground calculated location, using the GBM trigger
data, is RA = 99.1, DEC = -72.9 (J2000 degrees,
equivalent to 6 h 36 m, -72 d 54 '), with an uncertainty
of 8.8 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 119 degrees.
Since the source is weak, the time-averaged spectrum is poorly constrained."


GRB_name: GRB090516A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9422
SUBJECT: GRB 090516A: Konus-Wind and Swift/BAT joint spectral analysis
DATE:    09/05/24 17:27:29 GMT
FROM:    Takanori Sakamoto at NASA/GSFC  <takanori.sakamoto-1@nasa.gov>

T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC),
W. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD),
D. Palmer (LANL), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), and T. Ukwatta (GWU)

V. Pal'shin, S. Golenetskii, R.Aptekar, E. Mazets, D. Frederiks, and
T. Cline on behalf of the Konus-Wind team,
report:

We performed the Konus-Wind and the Swift/BAT joint spectral analysis
of GRB 090516A (Swift/BAT trigger #352190: Rowlinson et al., GCN Circ. 
9374, Baumgartner et al. GCN Circ. 9384).  Since the Konus-Wind observed 
this GRB in the waiting mode, we only have 3 channel spectral data for 
the Konus-Wind which cover the energy range from 20 keV to 1.2 MeV.  The 
joint spectral analysis of the Konus-Wind and the Swift/BAT data 
allows us to derive the broad-band spectral parameters of this burst.

The time interval of the spectral data for each instrument is chosen
from T0(BAT)-12.2 to T0(BAT)+96.7 sec where T0(BAT) is the trigger time
of BAT at 08:27:50.8 UTC.  The energy ranges which we used in the joint
spectral analysis are 20-1200 keV and 14-150 keV for the Konus-Wind and
the Swift/BAT respectively.  The spectral data of two instruments are
fitted with the spectral model multiplied by the constant factor to take
into account the systematic effective area uncertainties in the response
matrices of each instrument.

The spectrum is well fitted with a power-law with exponential cutoff 
model: dN/dE ~ E^{alpha}*exp(-(2+alpha)*E/Epeak). The constant factors 
of each instrument agree within 10%.  No systematic residual from the 
best fit model is seen in the spectral data of each instrument.  The 
best fit spectral parameters are: alpha = -1.5 (-0.3/+0.2) and Epeak 
= 190 (-65/+230) keV (chi2/dof = 54/56).  The best fit spectral 
parameters for the GRB (Band) model fixing beta = -2.5 are: 
alpha = -1.5 (-0.2/+0.3), and Epeak = 190 (-75/+270) keV (chi2/dof = 55/56).
The energy fluence in the 15-1200 keV band calculated by a power-law 
with exponential cutoff model for this 107.9 sec interval is 
(1.5 +/- 0.3)x10^-5 erg/cm2.

Assuming z = 4.109 (de Ugarte Postigo et al. GCN Circ. 9383) and a standard 
cosmology model with H_0 = 71 km/s/Mpc, Omega_M = 0.27, Omega_Lambda = 
0.73, the isotropic energy release is E_iso = 6.5 (-1.1/+1.4) x10^53 erg in 
1 keV to 10 MeV at the GRB rest frame extrapolating the best Band function fit 
fixing beta = -2.5.

The Konus-Wind light curve of this GRB is available at 
http://www.ioffe.ru/LEA/GRBs/GRB090516/ 

All the quoted errors are at the 90% confidence level.


GRB_name: GRB090518A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9423
SUBJECT: GRB 090518 - NOT upper limit
DATE:    09/05/26 07:21:31 GMT
FROM:    Johan U. Fynbo at U.Copenhagen  <jfynbo@astro.ku.dk>

C. C. Thoene (INAF/OAB), E. Kankare (NOT), J. P. U. Fynbo, D. Malesani
(DARK/NBI), A. J. Levan (Univ. Warwick), P. Jakobsson (Univ. Iceland),
J. Hjorth (DARK/NBI) report:

We observed the field of GRB 090518 (GCN 9386, Evans et al.) with
ALFOSC/NOT on La Palma starting May 18, 20:54 UT (21 h after the burst).
Observations were obtained in R (3x300s), I (3x300s) and z (6x200s)
filters at high airmass.

We do not detect any new source at the XRT position (GCN 9387, Evans et
al.) in the summed image of each filter. The following upper limits were
obtained (based on USNO B1.0 reference stars and a NOT z-band archival
zeropoint):

R > 23.7 mag
I > 21.8 mag
z(AB) > 22.5 mag


GRB_name: GRB090524A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9424
SUBJECT: GRB 090524: Fermi GBM detection
DATE:    09/05/26 15:20:47 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

A. von Kienlin (MPE) report on behalf of the Fermi GBM Team: 

"At 08:17:56.23 UT on 24 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090524 (trigger 264845878 / 090524346).
The on-ground calculated location, using the GBM trigger 
data, is RA = 329.5, DEC = -67.4 (J2000 degrees, 
equivalent to 21h 58m, 67d 24'), with an uncertainty 
of 1.3  degrees (radius, 1-sigma containment, 
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 63 degrees.

This burst was also independently detected by INTEGRAL SPI-ACS.

The GBM light curve consists of two main pulses
with a duration (T90) of about 72 s (8-1000 keV). 
The time-averaged spectrum from T0+0.003 s to T0+71.681 s is 
best fit by a Band function with Epeak = 82.6 +/- 6.3 keV, 
alpha = -1.00 +/- 0.08, and beta = -2.30 +/- 0.09
(chi squared 959 for 840 d.o.f.).

The event fluence (8-1000 keV) in this time interval is 
(1.85 +/- 0.15)E-05 erg/cm^2. The 1-sec peak photon flux measured 
starting from T0+5.120 s in the 8-1000 keV band 
is 14.1 +/- 1.4 ph/s/cm^2.

The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090522A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9425
SUBJECT: GRB 090522 : Fermi GBM detection
DATE:    09/05/27 12:46:59 GMT
FROM:    Sheila McBreen at MPE  <smcbreen@mpe.mpg.de>

Sheila McBreen (UCD/MPE) and Andreas von Kienlin (MPE)
report on behalf of the Fermi GBM Team:

"At 08:15:49.33 UT on 22 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090522 (trigger 264672951 / 090522344).

The on-ground calculated location, using the GBM trigger
data, is RA = 277.7, DEC = +19.6 (J2000 degrees,
equivalent to 18 h 31 m, +19 d 36 '), with an uncertainty
of 4.9 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).

The angle from the Fermi LAT boresight is 53 degrees.

The GBM light curve consists of one pulse
with a duration (T90) of about 22 s (8-1000 keV).
The time-averaged spectrum from T0-2 s to T0+20 s is
adequately fit by a power law function with an exponential
high energy cutoff.  The power law index is -1.03 (+ 0.41 / -0.53) and
the cutoff energy, parameterized as Epeak, is 75.8 (+36.9 / -15.9) keV
(chi squared 615 for 603 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(1.2 +/- 0.3)E-6 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+2 s in the 8-1000 keV band
is 3.5 +/- 0.2 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090518B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9426
SUBJECT: GRB090518B optical limit by "Pi of the Sky"
DATE:    09/05/27 13:54:07 GMT
FROM:    Marcin Sokolowski at Soltan Inst. Nuc Studies,Warsaw  <msok@fuw.edu.pl>

M.Cwiok, W.Dominik, G.Kasprowicz, A.Majcher, A.Majczyna,
K.Malek, L.Mankiewicz, K.Nawrocki, L.W.Piotrowski,
D.Rybka, M.Sokolowski, J.Uzycki, G.Wrochna, M.Zaremba, A.F.Zarnecki
on behalf of "Pi of the Sky" collaboration http://grb.fuw.edu.pl

The "Pi of the Sky" apparatus observed error box of Fermi GRB090518B
before, during and after the burst, starting 23 minutes before the
Fermi trigger. No new source brighter than 11 mag has been identified
on 10s exposures.


GRB_name: GRB090520B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9427
SUBJECT: GRB 090520B: Fermi GBM detection
DATE:    09/05/28 13:19:11 GMT
FROM:    Narayana Bhat at U Alabama/Huntsville/GBM  <Narayana.Bhat@nasa.gov>

P. N. Bhat (UAH) 
report on behalf of the Fermi GBM Team:

"At 19:57:53.98 UT on 20 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090520B (trigger 264542275 / 090520832).

[which was the second GRB trigger of the day while the first was
 detected by the Swift-BAT (Cummings et al. 2008, GCN 9417)]

The on-ground calculated location, using the GBM trigger
data, is RA = 332.0, DEC = 43.2 (J2000 degrees,
equivalent to 22 h 08 m, 43 d 12'), with an uncertainty
of 12 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 10 degrees.

The GBM light curve consists of a single pulse
with a duration (T90) of about 1.5 s (8-1000 keV).
The time-averaged spectrum from T0-0.384 s to T0+0.256 s is
adequately fit by a simple power law function with index -1.4 +/- 0.1

(chi squared 98 for 122 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(4.5 +/- 0.2)E-7 erg/cm^2. The 1-sec peak photon flux measured
starting from T0 s in the 8-1000 keV band
is 4.1 +/- 0.2 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090520C
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9428
SUBJECT: GRB 090520C: Fermi GBM detection
DATE:    09/05/28 13:32:02 GMT
FROM:    Narayana Bhat at U Alabama/Huntsville/GBM  <Narayana.Bhat@nasa.gov>

P. N. Bhat (UAH)
report on behalf of the Fermi GBM Team:

"At 20:23:19.31 UT on 20 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090520C (trigger 264543801 / 090520850).

The on-ground calculated location, using the GBM trigger
data, is RA = 111.2, DEC = -19.7 (J2000 degrees,
equivalent to 07 h 24.8 m, -19 d 42'), with an uncertainty
of 1.2 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 71 degrees.

The GBM light curve consists of single peak
with a duration (T90) of about 4.9 s (10-1000 keV).
The time-averaged spectrum from T0-0.512 s to T0+3.968 s is
adequately fit by a Band function with Epeak = 204.2 +/- 27.9 keV,
alpha = -0.73 +/- 0.09, and beta = -1.96 +/- 0.10

(chi squared 400.9for 362 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(3.54 +/- 0.25)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.872 s in the 8-1000 keV band
is 4.47 +/- 0.32 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090520D
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9429
SUBJECT: GRB 090520D: Fermi GBM detection
DATE:    09/05/28 13:45:04 GMT
FROM:    Narayana Bhat at U Alabama/Huntsville/GBM  <Narayana.Bhat@nasa.gov>

P. N. Bhat (UAH) 
reports on behalf of the Fermi GBM Team:

"At 21:01:37.14 UT on 20 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090520D (trigger 264546099 / 090520876).

The on-ground calculated location, using the GBM trigger
data, is RA = 131.3, DEC = -18.0 (J2000 degrees,
equivalent to 08 h 45.2 m, -18 d 0'), with an uncertainty
of 4.3 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 66 degrees.

The GBM light curve consists of single pulse
with a duration (T90) of about 12 s (8-1000 keV).
The time-averaged spectrum from T0-5.12 s to T0+13.3 s is
adequately fit by

a power law function with an exponential
high energy cutoff.  The power law index is -1.03 +/- 0.22 and
the cutoff energy, parameterized as Epeak, is 47.4 +/- 4.1 keV

(chi squared 354 for 363 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(4.0 +/- 0.9)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+2.0 s in the 8-1000 keV band
is 4.1 +/- 1.0 ph/s/cm^2.

A Band function fits the spectrum equally well (chi squared 353.8 for 362
d.o.f.) 
with Epeak= 46.3 +/- 5.3 keV, alpha = -0.99 +/- 0.28 and beta = -3.25 +/-
1.23. 


The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090529A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9430
SUBJECT: GRB 090529: Swift detection of a burst
DATE:    09/05/29 14:40:28 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

T. Sakamoto (NASA/UMBC), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU),
J. R. Cummings (NASA/UMBC), P. A. Evans (U Leicester),
O. Godet (U Leicester), C. Gronwall (PSU), C. Guidorzi (U Ferrara),
S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),
H. A. Krimm (CRESST/GSFC/USRA), V. Mangano (INAF-IASFPA),
J. Mao (INAF-OAB), R. Margutti (Univ Bicocca&OAB),
C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC),
P. T. O'Brien (U Leicester), J. P. Osborne (U Leicester),
K. L. Page (U Leicester), D. M. Palmer (LANL),
B. Sbarufatti (INAF-IASFPA), M. H. Siegel (PSU) and
T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:

At 14:12:35 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090529 (trigger=353540).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 212.474, +24.437 which is 
   RA(J2000)  = 14h 09m 54s
   Dec(J2000) = +24d 26' 13"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve does not show anything
but this is typical for an image trigger. 

The XRT began observing the field at 14:15:52.3 UT, 197.1 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source located at RA, Dec 212.46882,
24.45889 which is equivalent to:
   RA(J2000)  = 14h 09m 52.52s
   Dec(J2000) = +24d 27' 32.0"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 80 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (1.61e+20
cm^-2, Kalberla et al. 2005), with an excess column of 2.9
(+1.72/-1.51) x 10^21 cm^-2 (90% confidence). 

The initial flux in the 2.5 s image was 1.48e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 205 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.02. 

Burst Advocate for this burst is T. Sakamoto (Taka.Sakamoto AT nasa.gov). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090529A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9431
SUBJECT: GRB 090529: Xinglong TNT optical observation
DATE:    09/05/29 15:51:34 GMT
FROM:    L.P. Xin at NAOC  <xlp@bao.ac.cn>

L.P. Xin, W.K. Zheng, Y. Urata, Y.L. Qiu, J.Y. Wei, 
J. Wang, J.S. Deng and J.Y. Hu on behalf of EAFON report:

We have observed GRB 090529 (Sakamoto et al. GCN 9430)
with Xinglong TNT telescope from  May 29, 14:36:54 (UT),
24.3 min after the burst. After combined 20*20s white
band images and preliminary analysis, An new source was 
found in our combined image within the XRT errorbox. 
The brightness is estimated to be about R~19.4 mag 
derived from  USNO-B1.0 R2 magnitude, at the mean time 
of 28 min since the trigger.

The observation is still going.

This message may be cited.

For more information about Xinglong GRBs Follow-up
observations, please visit the website:
http://www.xinglong-naoc.org/grb/


GRB_name: GRB090529A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9432
SUBJECT: GRB 090529: Preliminary Swift/UVOT Upper Limit
DATE:    09/05/29 17:12:13 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <sholland@milkyway.gsfc.nasa.gov>

S. T. Holland (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC),
P. Schady (MSSL-UCL), and T. Sakamoto (NASA/UMBC) report on the behalf
of the Swift UVOT team:

      The Swift/UVOT took a 150 s exposure of the field of GRB 090529
with its white filter starting 204 s after the BAT trigger (Sakamoto,
et al., 2009, GCN Circ. 9430).  The preliminary 3-sigma upper limit at
the XRT position is white > 20.3.  This upper limit has not been
corrected for the expected Galactic extinction along the line of sight
corresponding to a reddening of E_{B-V} = 0.02 mag (Schlegel, et al.,
1998, ApJS, 500, 525).  The photometry is on the UVOT photometric
system described in Poole et al. (2008, MNRAS, 383, 627).

      The non-detection in the white filter at 204 s, combined with the
observation at 28 minutes of R ~ 19.4 (Xin, et al., 2009, GCN Circ.
9431) implies either that this afterglow is unusually red, or that it
has brightened during the first half hour after the BAT trigger.  Such
a long brightening would be highly unusual (Oates, et al., 2009,
MNRAS, 395, 450).


GRB_name: GRB090529A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9433
SUBJECT: GRB 090529: Enhanced Swift-XRT position
DATE:    09/05/29 19:11:24 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 2467 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 090529, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 212.46850, +24.45919 which is equivalent
to:

RA (J2000): 14h 09m 52.44s
Dec (J2000): +24d 27' 33.1"

with an uncertainty of 1.8 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, arXiv:0812.3662).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB090529A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9434
SUBJECT: GRB 090529:  Swift-BAT refined analysis 
DATE:    09/05/29 20:10:34 GMT
FROM:    Hans Krimm at NASA-GSFC  <hans.krimm@nasa.gov>

C. B. Markwardt (GSFC/UMD), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC),
T. N. Ukwatta (GWU) (i.e. the Swift-BAT team):

Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090529 (trigger #353540)
(Sakamoto, et al., GCN Circ. 9430).  The BAT ground-calculated position is
RA, Dec = 212.446, 24.450 deg which is
    RA(J2000)  =  14h 09m 47.1s
    Dec(J2000) = +24d 26' 58.5"
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 83%.

The mask-weighted light curve shows that the burst was in progress when it
came into the BAT field of view at ~T-50 sec, following a pre-planned slew.
The detectable part of the light curve shows an exponentially falling rate,
which some possible superimposed peaks at ~T-45, ~T-25 and ~T-15 sec.  The
count rate is down to background by T+50 seconds.  Given that we did not
observe the start of the burst, we can only provide a lower limit to T90:
T90 (15-350 keV) is > 100 sec.

The time-averaged spectrum from T-49.0 to T+39.3 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.00 +- 0.3.  The fluence in the 15-150 keV band is 6.8 +- 1.7 x 10-7 erg/cm2.
The 1-sec peak photon flux measured from T-50.0 sec in the 15-150 keV band
is 0.4 +- 0.1 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/353540/BA/


GRB_name: GRB090529A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9435
SUBJECT: GRB090529: UVOT/Swift detection of a brightening optical afterglow
DATE:    09/05/29 22:12:44 GMT
FROM:    Patricia Schady at MSSL/Swift  <ps@mssl.ucl.ac.uk>

P. Schady (MSSL-UCL), T. Sakamoto (NASA/UMBC), S. T. Holland 
(CRESST/GSFC/USRA) and F. E. Marshall (NASA/GSFC) report on behalf of the 
Swift UVOT team:

The Swift/UVOT began settled observations of the field of GRB 090529 206s 
after the BAT trigger (Sakamoto et al., GCN Circ. 9430) and no new source 
was detected within the XRT position in the first white finding chart (fc) 
(Sakamoto et al., GCN Circ. 9430; Holland et al., GCN Circ. 9432). 
However, a new source is detected within the refined XRT error circle 
(Osborne et al., GCN Circ. 9433) in a second white finding chart, taken at 
883s after the BAT trigger, as well as in a co-added b-band exposure at

RA (J2000)  14:09:52.56   =  212.46892 (deg)
Dec (J2000) +24:27:32.2   =  +24.45892 (deg)

with an estimated uncertainty of 0.7 arcsec (radius, 90% confidence, 
statistical + systematic). This source detection is consistent with the 
white band detection reported by Xin et al. (GCN Circ. 9431). We note that 
there is weak evidence that the source could be extended.

The magnitudes and 3-sigma upper limits for the observations currently 
available are as follows:

Filter      T_start(s)  T_stop(s)  Exp(s)   Mag/3-sigma UL

white_fc1     206        355        147        > 21.09
white_fc2     883        1032       147        20.81 +/- 0.22
white         1185       2587       175        21.55 +/- 0.31
v             363        2637       253        > 20.24
b             461        2564       233        20.97 +/- 0.36
b             2716  2824       107        > 20.70
u             436        2691       253        > 20.87
uvw1          412        2667       156        > 20.60
uvm2          387        2661       253        > 20.20
uvw2          510        2594       253        > 20.65

The values quoted above are not corrected for the Galactic extinction due 
to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel 
et al. 1998). The photometry is on the UVOT photometric system described 
in Poole et al. (2008, MNRAS, 383, 627).


GRB_name: GRB090529A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9436
SUBJECT: GRB 090529: TLS Afterglow Observations
DATE:    09/05/30 00:12:12 GMT
FROM:    Alexander Kann at TLS Tautenburg  <kann@tls-tautenburg.de>

D. A. Kann, U. Laux and B. Stecklum (TLS Tautenburg) report:

We observed the optical afterglow (Xin et al., GCN 9431) of the Swift GRB 
090529 (Sakamoto et al., GCN 9430) with the 1.34m Schmidt telescope of the 
Thueringer Landessternwarte Tautenburg, Germany. Observations began at 
twilight, which, together with the setting moon, caused an elevated sky 
background. Airmass was low and conditions were excellent until clouds 
came in during the last Rc image. We obtained 6 x 300 sec dithered images 
in the Ic band and 3 x 600 sec images in the Rc band. The afterglow is 
very faintly visible on several Ic frames, clearly visible on the first 
two Rc frames and hardly visible on the last Rc frame.

Using the USNOB1.0 catalog as a reference, we derive the following 
position (J2000) for the afterglow:

RA = 14:09:52.53
Dec. = +24:27:32.77

with an error of 0".5. This position lies 0".7 from the UVOT position 
(Schady et al., GCN 9435), in full agreement with it.

We find several sources of roughly similar magnitude within 10" of the 
afterglow. These may slightly affect the photometry.

To calibrate, we use the isolated star with USNO catalog # 1144-0210566 at 
position

RA = 14:09:47.50
Dec. = +24:27:44.5

which has R2 = 18.32 mag and I = 17.54 mag. (Note that it is 0.54 mag 
brighter in R1.)

We derive the following magnitudes 0.3 days after the GRB:

time (d) Mag dMag Exposure Filter

0.287871 20.98 0.13 6 x 300  Ic
0.304668 21.39 0.12 1 x 600  Rc
0.312191 21.40 0.12 1 x 600  Rc
0.319703 21.47 0.35 1 x 600  Rc

Compared to the magnitude found by Xin et al., GCN 9431, this indicates 
the afterglow has faded by two magnitudes. The normal Rc - Ic color as 
well as the confirmation by Swift UVOT of a rising afterglow (Schady et 
al., GCN 9435) implies that it is not overly reddened, an alternate 
explanation by Holland et al., GCN 9432.

No further observations are planned.

This message may be cited.


GRB_name: GRB090529A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9437
SUBJECT: GRB 090529: optical observations
DATE:    09/05/30 01:39:58 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

M. Andreev, A. Sergeev (Terskol Branch of Institute of Astronomy),  A. 
Pozanenko (IKI) on behalf of larger GRB follow up  collaboration report:

We observed the optical afterglow (Xin et al. GCN 9431) of the Swift GRB 
090529 (Sakamoto et al. GCN 9430) with the Z-600 telescope of Mt.Terskol 
observatory in R-filter between (UT) May 29 19:40 -- 20:20. In a combined 
image (20x120 s) we clearly detect the afterglow at the position (J2000) 
RA=14 09 52.55  Dec=+24 27 31.2 which is comparable with the afterglow 
position (Schady et al. GCN 9435, Kann et al. GCN 9436). The combined image 
finding chart can be found at 
http://grb.rssi.ru/GRB090529/GRB090529_Z600.JPG
The photometry of the afterglow is undergoing.


GRB_name: GRB090530A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9438
SUBJECT: GRB 090530: Swift detection of a burst with an optical counterpart
DATE:    09/05/30 03:30:01 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

J. K. Cannizzo (NASA/UMBC), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (NASA/UMBC),
C. Gronwall (PSU), S. T. Holland (CRESST/USRA/GSFC),
V. Mangano (INAF-IASFPA), C. B. Markwardt (CRESST/GSFC/UMD),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL),
T. Sakamoto (NASA/UMBC), B. Sbarufatti (INAF-IASFPA),
M. H. Siegel (PSU), M. Stamatikos (NASA/ORAU) and
T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:

At 03:18:18 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090530 (trigger=353567).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 179.395, +26.584 which is 
   RA(J2000) = 11h 57m 35s
   Dec(J2000) = +26d 35' 01"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a single peak
with a duration of about 10 sec.  The peak count rate
was ~5000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 03:19:33.1 UT, 74.7 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source located at RA, Dec 179.41927,
26.59282 which is equivalent to:
   RA(J2000)  = 11h 57m 40.62s
   Dec(J2000) = +26d 35' 34.2"
with an uncertainty of 3.9 arcseconds (radius, 90% containment). This
location is 84 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (1.78e+20
cm^-2, Kalberla et al. 2005), with an excess column of 2.1
(+2.01/-1.71) x 10^21 cm^-2 (90% confidence). 

The initial flux in the 2.5 s image was 6.42e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 83 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 11:57:40.50 = 179.41876
  DEC(J2000) = +26:35:38.6  = 26.59405
with a 90%-confidence error radius of about 0.75 arc sec. This position is 4.7
arc sec. from the center of the XRT error circle. The estimated magnitude is
17.39 with a 1-sigma error of about 0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.02. 

Burst Advocate for this burst is J. K. Cannizzo (cannizzo AT milkyway.gsfc.nasa.gov). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090530A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9439
SUBJECT: GRB 090530A: ROTSE-III Detection of Optical Counterpart
DATE:    09/05/30 03:30:24 GMT
FROM:    Heather Flewelling at IfA/Hawaii  <flewelling.heather@gmail.com>

H. Flewelling (IfA), B. E. Schaefer (Louisiana State), Shashi Pandey (UMich)
report on behalf of the ROTSE collaboration:

ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB 090530A
(Swift trigger 353567). The first image was at 03:18:35.8 UT, 17.4 s after
the burst (6.8 s after the GCN notice time). The unfiltered images are
calibrated relative to USNO A2.0. We detect a new object, not visible in the
DSS (second epoch), with coordinates:

     11:57:40.5      +26:35:37.9    (J2000), with positional uncertainty of
1" or better

start UT     mag     mlim(of image)
----------------------------------
03:18:42.7     16.0     16.2

A jpeg image is available at
http://www.rotse.net/images/gsb353567_3b00_img.jpg Note that the object
marked 48 is the candidate in question.

Continuing observations are in progress.


GRB_name: GRB090530A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9440
SUBJECT: GRB 090530: PAIRITEL NIR Detections
DATE:    09/05/30 04:30:03 GMT
FROM:    Adam Morgan at U.C. Berkeley  <qmorgan@gmail.com>

A. N. Morgan, D. A. Perley,  J. S. Bloom,  (UC Berkeley),  and D.
Starr (UCB, LCOGT) report:

We observed the field of GRB 090530 (Cannizzo et al., GCN 9438) with
the 1.3-m PAIRITEL located at Mt Hopkins, Arizona.  Observations began
at 2009-05-30 03:19:30 UT, 72 seconds after the Swift Trigger.  We
detect the optical afterglow (Cannizzo et al., GCN 9438, Flewelling et
al., GCN 9439) in mosaics taken simultaneously in the J, H, and Ks
filters.

The preliminary photometry yields:

post_burst
t_mid (min) exp(s)  filt  mag   merr
8.33        424     J     16.4  0.1
8.33        424     H     15.4  0.1
8.33        424     Ks    15.0  0.1

All magnitudes given in the Vega system, calibrated to 2MASS.  No
correction for Galactic extinction has been made to the above reported
values.  Observations are ongoing.

[GCN OPS NOTE(30may09); The typo in the Subject line was changed
from "090515" to "090530".]


GRB_name: GRB090530A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9441
SUBJECT: GRB 090530: GRAS002 optical observations
DATE:    09/05/30 09:13:47 GMT
FROM:    Veli-Pekka Hentunen at Taurus Hill Obs,A95  <veli-pekka.hentunen@kassiopeia.net>

Markku Nissinen (Taurus Hill Observatory) and Veli-Pekka Hentunen (Taurus
Hill Observatory) report:

We used Global-rent-a-scope GRAS002 Tak Mewlon 0.30m telescope with SBIG ST-8E
CCD at RAS Observatory Mayhill H06 (New Mexico, USA) for follow-up observations
of GRB090530 (J.K. Cannizzo et al., GCN 9438). The observations were started 
on May 30, at 05:30 UTC (2.2 hours after the burst) and stopped on May 30, 
at 06:16 UTC. Four unfiltered 600 seconds images were taken. We detected 
very faint optical afterglow object at the position of RA 11h 57m 39s.8 and 
Dec +26o 35' 47" (J2000) with possitional uncertainty of 10" with respect to
POSSII F/USNO-B1.0. This is in correlation with ROTSE-III optical counterpart
position (H. Flewelling et al., GCN 9439). Upper limit for the observations 
is >20.2 mag (3UL). Quoted upper limit has been derived using POSSII F and 
USNO-B1.0 field stars as reference.

                
Filter     Tmid(s)      Exp(s)     Mag (CR) USNO-B1.0
                
u         05:55:15      4x600      19.7
 

A jpeg preview of the observation showing the position of the afterglow is
at this URL: http://cutenews.kassiopeia.net/data/upimages/GRB090530A_new.jpg


GRB_name: GRB090530A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9442
SUBJECT: GRB 090530: GRAS002 refined OA analysis
DATE:    09/05/30 10:25:37 GMT
FROM:    Veli-Pekka Hentunen at Taurus Hill Obs,A95  <veli-pekka.hentunen@kassiopeia.net>

Markku Nissinen (Taurus Hill Observatory) and Veli-Pekka Hentunen (Taurus
Hill Observatory) report:
 

We used Global-rent-a-scope GRAS002 Tak Mewlon 0.30m telescope with SBIG ST-8E
CCD at RAS Observatory Mayhill H06 (New Mexico, USA) for follow-up observations
of GRB090530 (J.K. Cannizzo et al., GCN 9438). The observations were started 
on May 30, at 05:30 UTC (2.2 hours after the burst) and stopped on May 30, 
at 06:16 UTC. Four unfiltered 600 seconds images were taken. We detected 
very faint optical afterglow object at the position of RA 11h 57m 40s.6 and 
Dec +26o 35' 38".7 (J2000) with respect to POSSII F/USNO-B1.0 and this is in 
good correlation with ROTSE-III optical counterpart position (H. Flewelling 
et al., GCN 9439). Upper limit for the observations is >20.2 mag (3UL). Quoted
upper limit has been derived using POSSII F and USNO-B1.0 field stars as 
reference.

                
Filter     Tmid(s)      Exp(s)     Mag (CR) USNO-B1.0
                
u         05:55:15      4x600      19.2
 

A jpeg preview of the observation showing the position of the afterglow is
at this URL: http://cutenews.kassiopeia.net/data/upimages/GRB090530.jpg


GRB_name: GRB090530A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9443
SUBJECT: GRB 090530: Swift-BAT refined analysis
DATE:    09/05/30 12:34:07 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. K. Cannizzo (NASA/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090530 (trigger #353567)
(Cannizzo, et al., GCN Circ. 9438).  The BAT ground-calculated position is
RA, Dec = 179.400, 26.590 deg, which is 
   RA(J2000)  =  11h 57m 36.0s 
   Dec(J2000) = +26d 35' 23.0" 
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 41%.
 
The mask-weighted light curve shows a FRED-like peak starting at ~T-0.3 sec,
peaking at ~T+0.2 sec, and returning almost to background.  Then a second and
much smaller peak starts at ~T+35 sec, peaks at ~T+45 sec, and ends
at ~T+50 sec.  There is an ~3-sigma precursor peak at T-4sec.  T90 (15-350 keV)
is 48 +- 36 sec (estimated error including systematics).
 
The time-averaged spectrum from T-12.2 to T+51.8 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.61 +- 0.17.  The fluence in the 15-150 keV band is 1.1 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+0.0 sec in the 15-150 keV band
is 2.5 +- 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/353567/BA/


GRB_name: GRB090530A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9445
SUBJECT: GRB 090530: Enhanced Swift-XRT position
DATE:    09/05/30 15:15:48 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 646 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 090530, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 179.41846, +26.59341 which is equivalent
to:

RA (J2000): 11h 57m 40.43s
Dec (J2000): +26d 35' 36.3"

with an uncertainty of 1.5 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, arXiv:0812.3662).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB090528A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9446
SUBJECT: GRB 090528: Fermi GBM detection
DATE:    09/05/30 15:34:09 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: 

"At 04:09:01.14 UT on 28 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090528 (trigger 265176543 / 090528173).
The on-ground calculated location, using the GBM trigger 
data, is RA = 134.9, DEC = -35.8 (J2000 degrees, 
equivalent to 09h 00m, -35d 48'), with an uncertainty 
of 3.4 degrees (radius, 1-sigma containment, 
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
The GBM on-ground location is within two sigma of the 
Vela X-1 position, nevertheless we think this event 
is due to a real gamma-ray burst because intensity, duration 
and spectrum are unusual for Vela X-1 observed outburst.
 
The angle from the Fermi LAT boresight is 81 degrees.

The GBM light consists of one major structured pulse
with a duration (T90) of about 68 s (8-1000 keV). 
The time-averaged spectrum from T0-5.120  s to T0+29.696 s is 
well fit by a power law function with an exponential
high energy cutoff.  The power law index is -1.7 +/- 0.1 and
the cutoff energy, parameterized as Epeak, is 99 +/- 26 keV
(chi squared 357 for 359 d.o.f.).

The event fluence (8-1000 keV) in this time interval is 
(9.3 +/- 0.9)E-06 erg/cm^2. The 1-sec peak photon flux measured 
starting from T0+3.072 s in the 8-1000 keV band 
is 7.6 +/- 0.3 ph/s/cm^2.

The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090528B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9447
SUBJECT: GRB 090528B: Fermi GBM detection
DATE:    09/05/30 15:35:59 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: 

"At 12:22:31.29 UT on 29 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090528B (trigger 265206153 / 090528516).
The on-ground calculated location, using the GBM trigger 
data, is RA = 312.2, DEC = 32.7 (J2000 degrees, 
equivalent to 20h 49m, 32d 42'), with a statistical uncertainty 
of less than 1 degree (radius, 1-sigma containment) and an additional 
systematic error which is currently estimated to be 2 to 3 degrees.
The angle from the Fermi LAT boresight is 65 degrees.

This burst was also independently detected by INTEGRAL SPI-ACS.

The GBM light curve shows a strong multiple peak event follwed by 
a weaker structered tail with a duration (T90) of about 102 s (8-1000 keV). 
The time-averaged spectrum from T0-2.048 s to T0+57.345 s is 
best fit by a Band function with Epeak = 172 +/- 12  keV, 
alpha = -1.10 +/- 0.04, and beta = -2.3 +/- 0.1
(chi squared 516 for 477 d.o.f.).

The event fluence (8-1000 keV) in this time interval is 
(4.65 +/- 0.15)E-05 erg/cm^2. The 1-sec peak photon flux measured 
starting from T0+9.216 s in the 8-1000 keV band 
is 14.7 +/- 1.3 ph/s/cm^2.

The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090529A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9448
SUBJECT: GRB 090529: OSN optical observations
DATE:    09/05/30 16:04:33 GMT
FROM:    Javier Gorosabel at Danish Space Res Inst  <jgu@space.dtu.dk>

J. Gorosabel (IAA-CSIC), A. de Ugarte Postigo (ESO, Santiago),
F.J. Aceituno (OSN, IAA-CSIC), A.J. Castro-Tirado (IAA-CSIC), report
on behalf of a larger collaboration:

"We carried out R-band observations of the GRB 090529 XRT error circle
(Sakamoto et al. GCN 9430; Osborne et al. GCN 9433) with the 1.5m OSN
telescope. On May 29.87-29.93 UT (0.27-0.33 days afer the GRB) we detected
the optical afterglow (Xin et al. GCN 9431) at R=21.44+/-0.06, against the
same reference star used by Kann et al. (GCN 9436)."

This message can be quoted.


GRB_name: GRB090529A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9449
SUBJECT: GRB 090529: Swift-XRT refined analysis
DATE:    09/05/30 16:48:02 GMT
FROM:    Boris Sbarufatti at INAF-IASF-Pa  <sbarufatti@ifc.inaf.it>

Sbarufatti B., Mangano V. (INAF-IASFPA) and T. Sakamoto (NASA/UMBC)
report on behalf of the Swift Team:

We have analyzed the first eleven orbits of Swift-XRT data of
GRB 090529 (trigger 353540; Sakamoto, et al., GCN Circ. 9430),
comprising 148 s taken in Windowed Timing (WT) mode, from T+203 s
to T+352 s, and 8.2 ks in Photon Counting (PC)
mode from T+353 s to T+46.7 ks.

The best position for the X-ray afterglow is the XRT UVOT-enhanced
position:RA, Dec = 212.46850, +24.45919 which is equivalent
to:

RA (J2000): 14h 09m 52.44s
Dec (J2000): +24d 27' 33.1"

with an uncertainty of 1.8 arcsec (radius, 90% confidence), as given
by Osborne, et al., GCN Circ 9433.

The 0.3-10 keV X-ray light curve is best fitted by a broken power-law
wit early  decay index -3.5+/-0.1, late decay index -0.7+/-0.2 and the
break at (1100+180-140) s after the trigger. Faint flaring activity is
detected along the decay. If decaying at the present rate, the
predicted rate for T+ 48h is 2.8e-3 counts/s. However, we remark that
a second break followed by a steepening of the light-curve is
expected. The issue will be clarified when new data from the Swift
observations (resumed today at 14:35 UT) will be available.

The average spectrum of the steep decay part of the afterglow (WT + PC
from T+203s to T+1.1 ks) is best fit by a power-law with indices
2.5+/-0.12 for the WT data and 2.2+/-0.15 for the PC data. The
absorbing column is NH = (2.3-1.5+1.7)E20 cm^-2 slightly in excess
with respect to the Galactic value of 1.61E20 cm^-2 (Kalberla et
al. 2005). The average observed (unabsorbed) fluxes are
4.5(5.1)E-10 ergs cm^-2 s^-1 for the WT data and 1.5(1.6)E-11 for the
PC data.
The average spectrum of the flat decay part of the afterglow,
consisting of 7.5 ks of PC data, observed from T+1.1 ks to T+46.7 ks
(containing 120 photons) was fitted using Cash statistics with an
absorbed power-law model. The absorbing column NH is (9 -7 +9)E20
cm^-2, consistent with the Galactic value, the photon index is
2.3+/-0.5. The observed (unabsorbed) flux is 5.3(7.2)E-13 ergs cm^-2
s^-1. The C-statistic is 66.4 with 101 bins.
The count-rate to flux conversion factor is 4.7E-11.
All quoted errors are at 90% confidence level.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00353540.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090530A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9450
SUBJECT: GRB090530: Swift/UVOT afterglow detection
DATE:    09/05/30 17:08:39 GMT
FROM:    Patricia Schady at MSSL/Swift  <ps@mssl.ucl.ac.uk>

P. Schady (MSSL-UCL) and J. K. Cannizzo (NASA/UMBC) report on behalf of 
the Swift UVOT team:

The Swift/UVOT began settled observations of the field of GRB 090530 158s 
after the BAT trigger (Cannizzo et al., GCN Circ. 9438) and a decaying 
source is detected in all UVOT filters within the XRT error circle 
(Beardmore et al., GCN Circ. 9445), putting an upper limit on the redshift 
of z < 1.7. The source initially rises, and at around 100s after the BAT 
trigger decays at a constant rate of 0.73+/-0.03 for the duration of 
intial UVOT observations, out to ~20ks after the BAT trigger.  The best 
UVOT position determined from a co-added white band exposure is

RA (J2000)  11:57:40.50   =  179.41873 (deg)
Dec (J2000) +26:35:38.4   =  +26.59400 (deg)

with an estimated uncertainty of 0.5 arcsec (radius, 90% confidence, 
statistical + systematic), consistent with the ROTSE-IIIb afterglow 
position (Flewelling et al., GCN Circ. 9439).

The magnitudes for the observations currently available are as follows:

Filter   T_start(s)  T_stop(s)  Exp(s)       Mag
white       83         233       147    17.43 +/- 0.03
v           624        644       19     17.69 +/- 0.29
b           550        570       19     18.60 +/- 0.27
u           295        545       246    17.46 +/- 0.05
uvw1        5735       5935      197    20.15 +/- 0.37
uvm2        5530       11687     1082   20.31 +/- 0.22
uvw2        5121       17468     1279   21.31 +/- 0.32

The values quoted above are not corrected for the Galactic extinction due 
to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel 
et al. 1998). The photometry is on the UVOT photometric system described 
in Poole et al. (2008, MNRAS, 383, 627).


GRB_name: GRB090530A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9451
SUBJECT: GRB090530: Swift XRT refined analysis
DATE:    09/05/30 21:09:24 GMT
FROM:    Vanessa Mangano at INAF-IASFPA  <vanessa@ifc.inaf.it>

Mangano V., Sbarufatti B. (INAF-IASFPA), J. K. Cannizzo (NASA/UMBC)
report on behalf of the Swift XRT Team:

We have analyzed the first five orbits of Swift-XRT data of
GRB 090530 (trigger 353567; Cannizzo, et al., GCN Circ. 9438),
consisting of 22 s in Windowed Timing (WT) mode from T+81 to T+103 s and
9 ks in Photon Counting (PC) mode from T+105 s to T+24.4 ks.

The best position for the X-ray afterglow is the XRT UVOT-enhanced
position: RA, Dec = 179.41846, +26.59341 which is equivalent to:

RA (J2000): 11h 57m 40.43s
Dec (J2000): +26d 35' 36.3"

with an uncertainty of 1.5 arcsec (radius, 90% confidence), as given
by Beardmore, et al., GCN Circ 9445.

The 0.3-10 keV X-ray light curve is best fitted by a broken powerlaw
with early decay index of about -5.7, late decay index -0.60+/-0.04
and a break at about 140 s after the trigger. In the first orbit
a small amplitude flare is detected at T+300 s. Flaring activity
is also visible along the later decay.
If decaying at the present rate, the predicted rate after 24h from the
trigger is 2.0e-2 counts/s. However, we remark that a second break
followed by a steepening of the lightcurve is possibly expected.
The issue will be clarified with following Swift observations that
will resume on Sunday May 31st.

The average initial WT spectrum (covering the initial steep decay)
can be modeled as an absorbed power-law with index 2.3 (+0.5-0.4),
absorbing column NH < 11E20 cm-2 (three sigma upper limit) and
observed(unabsorbed) average flux in the 0.3-10 keV energy range of
2.9(3.6)E-10 ergs cm-2 s-1.
The average PC spectrum (roughly covering the flatter part of the
afterglow)
is best fitted by an absorbed power-law with index 2.00+/-0.15
The absorbing column is NH = (8.2 -2.9+3.6)E20 cm-2 in excess with
respect to the Galactic value of 1.78E+20 cm-2 (Kalberla et al. 2005).
The average observed(unabsorbed) flux is 4.0(4.9)E-12 ergs cm-2 s-1.
The count-rate to flux conversion factor is 5.4E-11.
All quoted errors are at 90% confidence level.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00353567.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090530A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9452
SUBJECT: GRB 090530: NOT optical observations
DATE:    09/05/30 23:26:56 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@astro.ku.dk>

D. Malesani, D. Xu, G. Leloudas, J.P.U. Fynbo (DARK/NBI), P. Jakobsson 
(Univ. Iceland), M.E. Brown (Caltech), E.L. Schaller (Univ. Hawaii), and 
T. Liimets (NOT & Tartu Obs.) report on behalf of a larger collaboration:

We observed the field of GRB 090530 (Cannizzo et al., GCN 9438) with the 
NOT equipped with the MOSCA camera. Observations were carried out in the 
R band, starting on 2009 May 30.879 UT (17.8 hr after the GRB).

The optical afterglow (Cannizzo et al., GCN 9438; Flewelling et al., GCN 
9439; Morgan et al., GCN 9440) is clearly detected in a single 300s 
exposure, with a magnitude R = 21.6 assuming R = 18.17 for the USNO star 
at RA = 11:57:41.68, Dec = +26:35:43.3.


GRB_name: GRB090529A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9453
SUBJECT: GRB 090529: NOT optical observations
DATE:    09/05/30 23:53:10 GMT
FROM:    Giorgos Leloudas at Dark Cosmology Centre  <giorgos@dark-cosmology.dk>

G. Leloudas, D. Malesani, D. Xu, J.P.U. Fynbo (DARK/NBI), P.  
Jakobsson (Univ. Iceland),
M. E.  Brown (Caltech), E.L. Schaller (Univ. Hawaii) and T. Liimets  
(NOT & Tartu Obs.)
report on behalf of a larger collaboration:

We observed the field of GRB 090529 (Sakamoto et al., GCN 9430) with  
the Nordic Optical Telescope equipped with MOSCA.
3x600s R-band frames were obtained starting on May 30, 21:22 UT, 1.29  
days after the GRB.

The optical afterglow (Xin et al., GCN 9431; Schady et al., GCN 9435)  
is well detected in our images. Using the same reference star as in  
Kann et al. (GCN 9436), we obtain R=22.5 for the afterglow.

Comparison with the measurement by Kann et al., taken 0.3 days after  
the GRB, provides a decay index alpha = 0.72, assuming a power-law F 
(t) propto t^-alpha.


GRB_name: GRB090531A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9454
SUBJECT: GRB 090531: Swift detection of a burst
DATE:    09/05/31 01:56:55 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

M. Stamatikos (NASA/ORAU), S. D. Barthelmy (GSFC), C. Gronwall (PSU),
S. T. Holland (CRESST/USRA/GSFC), V. Mangano (INAF-IASFPA) and
D. M. Palmer (LANL) report on behalf of the Swift Team:

At 01:45:17 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090531 (trigger=353627).  Swift could not immediately slew
to the burst location.  The BAT on-board calculated location is 
RA, Dec 178.687, +7.799 which is 
   RA(J2000) = 11h 54m 45s
   Dec(J2000) = +07d 47' 58"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single-peaked
structure with a duration of about 50 sec.  The peak count rate
was ~1500 counts/sec (15-350 keV), at ~10 sec after the trigger. 

Because of a Moon constraint, Swift could not slew, and there
will be no XRT or UVOT observations until June 3. 

Burst Advocate for this burst is M. Stamatikos (michael AT milkyway.gsfc.nasa.gov). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090531A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9455
SUBJECT: GRB 090531: P60 Observations
DATE:    09/05/31 07:07:45 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko@srl.caltech.edu>

S. B. Cenko (UC Berkeley) reports on behalf of a larger collaboration:

We have imaged the field of GRB090531 (Stamatikos et al., GCN 9454) with
the automated Palomar 60 inch telescope.  Observations began at 4:47 UT on
2009 May 31 (~ 4.03 hr after the burst trigger) and were taken in the
Sloan r', i', and z' filters.  In coadded images, we find no new sources
inside the BAT error circle to the following limits (calculated
with reference to the SDSS DR7):

Filter  Magnitude  Time Since Burst (hours)
----------------------------------------------------------------------
r'  > 21.5   4.22
i'  > 21.3   4.25
z'  > 20.5   4.30


GRB_name: GRB090531A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9456
SUBJECT: GRB 090531: GROND upper limits
DATE:    09/05/31 08:07:23 GMT
FROM:    Andrea Rossi at TLS Tautenburg  <rossi@tls-tautenburg.de>

A. Rossi (Tautenburg), F. Olivares, and J. Greiner (both MPE Garching)
report on behalf of the GROND team:

We observed the field of GRB 090531 (Swift trigger 353627, Stamatikos et al.,
GCN #9454) simultaneously in g'r'i'z'JHK with GROND mounted at the 2.2m
MPI/ESO telescope at La Silla Observatory (Chile). Observations started on
31 May 2009 at 01:47 UT, 2 minutes after the burst and continued until
03:29 UT.

We do not find any new source within the BAT error circle. Image subtraction
between the first and last images of each band does not reveal any variable
source. The first image , consisting of 4.4 min exposure in g'r'i'z' and
4 min in JHK, yields the following upper limits (all AB):

g' > 22.6
r' > 22.8
i' > 22.4
z' > 22.0
J  > 21.5
H  > 20.9
K  > 20.2

which were obtained using the SDSS and 2MASS field stars as reference.


GRB_name: GRB090529A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9457
SUBJECT: GRB 090529: VLT spectroscopic redshift
DATE:    09/05/31 10:39:47 GMT
FROM:    Valerio D'Elia at INAF-OAR  <delia@oa-roma.inaf.it>

D. Malesani, J. P. U. Fynbo, (DARK/NBI), V. D'Elia (INAF/OAR), 
A. de Ugarte Postigo (ESO), P. Jakobsson (U. Iceland), 
C. C. Thoene (INAF/OAB), report on behalf of a larger collaboration:

Using FORS2 on the ESO Very Large Telescope, we have obtained 
low-resolution spectra (2 x 30 min) of the optical afterglow of GRB 
090529 (Sakamoto et al., GCN 9430; Xin et al., GCN 9431) with the grism 
300V, covering the wavelength range 3500-9200 AA. In the acquisition 
image the afterglow has a magnitude of R ~ 22.60 +-0.05. The first spectrum 
was taken starting on May 31.0778 UT (1.48 days after the GRB).

In a preliminary analysis we detect strong absorption around 4416 AA
which we interpret as Lyman-alpha at a redshift of 
z = 2.63. This value is supported by the detection of several metal
absorption features, e.g., SiII 1526, CII 1335, SiII 1402 and CIV 1549, all
at the common z=2.625, which we interpret as the redshift of the GRB. 

We thank the Paranal staff for excellent support, in particular 
Thomas Szeifert, Alain Smette, and Karla Aubel. We are also grateful to Lipin Xin 
for providing us with a finding chart.



-------------------------------------------------
This mail sent through IMP: http://horde.org/imp/


GRB_name: GRB090530A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9458
SUBJECT: GRB 090530: break in light curve
DATE:    09/05/31 12:36:48 GMT
FROM:    Jochen Greiner at MPI  <jcg@mpe.mpg.de>

A. Rossi (Tautenburg), F. Olivares, and J. Greiner (both MPE Garching)
report on behalf of the GROND team:

We observed the field of GRB 090530 (Swift trigger 353567, Cannizzo et al.,
GCN #9438) simultaneously in g'r'i'z'JHK with GROND mounted at the 2.2m
MPI/ESO telescope at La Silla Observatory (Chile). Observations started on
31 May 2009 at 00:36 UT, 21.3 h after the burst.

We detect the optical/NIR afterglow (Cannizzo et al., GCN #9438;
Flewelling et al., GCN #9439; Morgan et al., GCN #9440; Nissinen & Hentunen,
GCN #9442) in stacked exposures of 20 min in JHK and 24 min in g'r'i'z'. 

Calibrating the r' band data against the USNO star at RA = 11:57:41.7, 
Dec = +26:35:43, we obtain R = (22.2 +-0.2) mag. Comparing this with 
the white light magnitudes obtained by ROTSE (Flewelling et al., GCN #9439),
UVOT (Schady et al., GCN #9450) and GRAS002 (Nissinen & Hentunen,
GCN #9442) as well as the NOT R-band magnitude (Malesani et al., GCN #9452),
we find a break in the optical light at around 22 ksec post-burst (i.e.
before the NOT observation), with slopes of 0.5+-0.1 (pre-break) and 
1.8+-0.4 (post-break).  We note that a break at this time is also visible
in the Swift/XRT data (see repository; Evans et al. 2007).


GRB_name: GRB090530A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9459
SUBJECT: GRB090530: R-band Observation
DATE:    09/05/31 14:49:20 GMT
FROM:    Myungshin Im at Seoul Nat U  <mim@astro.snu.ac.kr>

  M. Im (CEOU/Seoul National Univ) and Y. Urata (NCU)
  on behalf of EAFON team.

   We observed GRB090530 (Cannizzo et al. GCN 9438) in R using
  the 1.0m telescope at Mt. Lemmon (Arizona, US) operated by
  the Korea Astronomy Space Science Institute.
   The R-band imaging started at 2009 May 30, 04:18:02 UT
  (~1 hr after the burst), with the mid-point at May 30,
  04:45 UT.

   In a stacked image of 9 frames (3 min exp. each),
  the optical afterglow is clearly detected
  at R=19.6 +- 0.15 mag.
   The photometry was calibrated against R2mag of USNO-B1 stars
  in the vicinity of GRB.

   We thank the LOAO operator, J. Yoon for his assistance for this
  observation.


GRB_name: GRB090531A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9460
SUBJECT: GRB 090531: Swift-BAT refined analysis
DATE:    09/05/31 16:36:42 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL),
G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC),
T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-60 to T+243 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 090531 (trigger #353627)
(Stamatikos, et al., GCN Circ. 9454).  The BAT ground-calculated position is
RA, Dec = 178.672, 7.824 deg, which is 
   RA(J2000)  =  11h 54m 41.4s 
   Dec(J2000) = +07d 49' 27.0" 
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 73%.
 
The mask-weighted light curve shows a single peak starting at ~T-25 sec,
peaking at T+9 sec, and ending at ~T+60 sec.  There is a possible (2.5 sigma CL)
episode of emission from T+80 to ~T+140 sec.  T90 (15-350 keV) is 32 +- 6 sec
(estimated error including systematics).
 
The time-averaged spectrum from T-12.6 to T+29.4 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 0.86 +- 0.42, 
and Epeak of 64.7 +- 14.3 keV (chi squared 51.91 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 1.3 +- 0.1 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T+9.29 sec in the 15-150 keV band is
1.3 +- 0.2 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.68 +- 0.09 (chi squared 65.50 for 57 d.o.f.).  All the quoted errors
are at the 90% confidence level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/353627/BA/


GRB_name: GRB090531B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9461
SUBJECT: GRB 090531B: Swift detection of a burst
DATE:    09/05/31 18:44:29 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

J. R. Cummings (NASA/UMBC), S. D. Barthelmy (GSFC),
N. Gehrels (NASA/GSFC), C. Gronwall (PSU),
S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),
V. Mangano (INAF-IASFPA), C. B. Markwardt (CRESST/GSFC/UMD),
P. T. O'Brien (U Leicester), K. L. Page (U Leicester),
D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC) and
B. Sbarufatti (INAF-IASFPA) report on behalf of the Swift Team:

At 18:35:56 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090531B (trigger=353728).  Swift will execute a delayed slew
to the burst. 
The BAT on-board calculated location is 
RA, Dec 252.064, -36.025 which is 
   RA(J2000)  =  16h 48m 15s
   Dec(J2000) = -36d 01' 27"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows an initial bright spike
at T_zero, then two much smaller spikes at T+21 sec and T+35 sec. 
The peak count rate was ~7000 counts/sec (15-350 keV), at ~0 sec
after the trigger. 

Due to an observing constraint, Swift will not slew until 
T0+50.1 minutes. There will be no XRT or UVOT data until
this time. 

Burst Advocate for this burst is J. R. Cummings (jayc AT milkyway.gsfc.nasa.gov). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090531B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9462
SUBJECT: GRB 090531B: ROTSE-III Optical Limits 
DATE:    09/05/31 19:20:55 GMT
FROM:    Brad Schaefer at LSU  <schaefer@grb.phys.lsu.edu>

B. E. Schaefer (Louisiana State), T. Guver (U Arizona), S. B. Pandey (U 
Mich), report on behalf of the ROTSE collaboration:

ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia, 
responded to GRB 090531B (Swift trigger 353728; J. R. Cummings et al., GCN 
9461), producing images beginning 7.3 s after the GCN notice time. An 
automated response took the first image at 18:36:22.3 UT, 26.1 s after the 
burst, and during the gamma-ray emission, under excellent conditions. We 
took 10 5-sec, 10 20-sec and 50 60-sec exposures. These unfiltered images 
are calibrated relative to USNO A2.0 (R). Imaging is on going.

Comparison to the DSS (second epoch) reveals no new sources within the 
3-sigma Swift/BAT error circle, for both single images and coadding into 
sets of 10; however, we are limited as the field is somewhat crowded. 
Individual images have limiting magnitudes ranging from 15.3-16.0; we set 
the following specific limits.

start UT       end UT      t_exp(s)   mlim   t_start-tGRB(s)  Coadd?
--------------------------------------------------------------------
18:36:22.3   18:36:27.3         5     15.3           26.1       N
18:47:31.3   18:52:11.6       280     16.3          695.1       Y

[GCN OPS NOTE(31may09):  Per author's request, the "B" was added
to the burst name.]


GRB_name: GRB090531B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9463
SUBJECT: GRB 090531B: Swift-XRT candidate afterglow position
DATE:    09/05/31 20:27:50 GMT
FROM:    Boris Sbarufatti at INAF-IASF-Pa  <sbarufatti@ifc.inaf.it>

B. Sbarufatti, V. Mangano (INAF-IASFPA) and
J. R. Cummings (NASA/UMBC) report on behalf of the
Swift-XRT team


The XRT began observing the field of GRB 090531B
(trigger 353728, Cummins,  et al., GCN Circ 9461) at
19:26:22 UT, 3026 seconds after the BAT trigger, as
soon as the burst went outside the Earth limb observing
constraint.
Using promptly downlinked data we find an X-ray
source with an enhanced position: RA,Dec = 252.0748, -36.0350
(degrees) which is equivalent to:

RA  (J2000) = 16 48 17.95
DEC (J2000) = -36 02 06.0

with an uncertainty of 3.4 arcsec (radius, 90% containment).
This location is 47.8 arcseconds from the BAT onboard position, inside  
the BAT
error circle.

This circular is an official product of the Swift-XRT team.

[GCN OPS NOTE(03sep09): Per operator's desire, the Subject line
was corrected from "090831B" to "090531B". F.Marshall and H.Krimm noticed this.]


GRB_name: GRB090531B
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9464
SUBJECT: Initial Swift/UVOT observations of GRB 090531B
DATE:    09/05/31 20:49:26 GMT
FROM:    Caryl Gronwall at PSU/Swift-UVOT  <caryl@astro.psu.edu>

C. Gronwall (PSU) and J. R. Cummings (NASA/UMBC) report on behalf of  
the UVOT Team:

In response to GRB090531B (Swift/BAT trigger 353728; Cummings et al.,  
GCN Circ. 9461)
at 18:35:56 UT, UVOT took a finding chart exposure of 150 seconds with  
the White filter
starting 3848 seconds after the BAT trigger. No credible afterglow  
candidate has been
found in the initial data products. The 2.7'x2.7' sub-image covers  
100% of the XRT
error circle (Sbarufatti et al., GCN Circ. 9463) The typical 3-sigma  
upper limit has
been about 19.6 mag.  No correction has been made for the expected  
extinction corresponding
to E(B-V) of 1.12.


GRB_name: GRB090531B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9465
SUBJECT: GRB 090531B: Swift-BAT refined analysis
DATE:    09/06/01 00:03:02 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

T. N. Ukwatta (GWU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC)
(i.e. the Swift-BAT team):
 
Using the data set from T-61 to T+242 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090531B (trigger #353728)
(Cummings, et al., GCN Circ. 9461).  The BAT ground-calculated position is
RA, Dec = 252.070, -36.015 deg, which is 
   RA(J2000)  =  16h 48m 16.8s 
   Dec(J2000) = -36d 00' 53.4" 
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.
 
The mask-weighted light curve shows an initial bright spike with a total
width of 1.3 sec.  It returns to baseline and then starts (!T+15 sec)
a long smooth rise to a peak around T+40 sec and a smooth decline
ending at ~T+110 sec.  The spike is spectrally harder than the long smooth peak.
This lightcurve is consistance with a short hard burst with an extended emission.
T90 (15-350 keV) is 80 +- 23 sec (estimated error including systematics).
 
The time-averaged spectrum from T-13.0 to T+67.0 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.51 +- 0.22.  The fluence in the 15-150 keV band is 7.1 +- 0.9 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.2 sec in the 15-150 keV band
is 1.25 +- 0.1 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/353728/BA/


GRB_name: GRB090530A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9466
SUBJECT: GRB 090530: GRT Optical Observation
DATE:    09/06/01 01:50:08 GMT
FROM:    Takanori Sakamoto at NASA/GSFC  <takanori.sakamoto-1@nasa.gov>

T. Sakamoto (UMBC/GSFC), D. Donato (ORAU/GSFC), N. Gehrels (GSFC),  
T. Okajima (JHU/GSFC), T. N. Ukwatta (GWU/GSFC), Y. Urata (NCU),  
C. Wallace (FGCU) 
  
We observed the field of GRB 090530 detected by Swift (trigger #353567;  
Cannizzo et al., GCN #9438) with the 14-inch Goddard Robotic Telescope (GRT)  
located at the Goddard Geophysical and Astronomical Observatory  
(http://cddisa.gsfc.nasa.gov/ggao/).   
 
100 set of 30 sec exposures were taken in the R filter starting 
from May 30 03:33:00 (UT) about 15 min after the trigger and 
stopped on May 30 04:29:30 (UT).  We do not detect the optical 
afterglow (Cannizzo et al., GCN #9438, Flewelling et al., GCN #9439, 
Nissinen et al., GCN #9441, Malesani et al., GCN #9452, Im et al., 
GCN #9459) both in the individual images and the combined image.  
The estimated three sigma upper limit of the combined image (total 
exposure of 3000 sec) is ~18.1 mag using the USNO-B1 catalog. 


GRB_name: GRB090529A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9467
SUBJECT: GRB 090529: MITSuME optical observation
DATE:    09/06/01 07:55:52 GMT
FROM:    Michitoshi Yoshida at Okayama Astrophysical Obs  <yoshida@oao.nao.ac.jp>

M. Yoshida, D. Kuroda, K. Yanagisawa, Y. Shimizu, S. Nagayama,
H. Toda (OAO, NAOJ) and N. Kawai (Tokyo Tech) report on behalf
of the MITSuME collaboration:

We observed the field of GRB 090529 (Sakamoto et al. GCN 9430)
with optical three color (g', Rc and Ic) CCD camera attached to
the MITSuME 50cm telescope of Okayama Astrophysical Observatory.
The observation started on 2009-05-29 14:51:47 UT. We found a
faint source at the UVOT position reported by Schady et al. (GCN
9435) in g' band.

Photometric results are listed below. We used USNO B1 catalog
for flux calibration.

#PDAY      MID-UT   T-EXP     g'   g'_err     Rc      Ic
----------------------------------------------------------
0.03564  15:03:55  1200sec   20.3   0.4     >19.7   >18.9
----------------------------------------------------------


GRB_name: GRB090528B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9468
SUBJECT: GRB 090528B: MASTER-II Kourovka  optical limit 
DATE:    09/06/01 08:30:40 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc@observ.inetcomm.ru>

V.Krushinski, I.Zalognikh, A.Popov, T.Kopytova
Ural State University, Kourovka

E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina,
D.Kuvshinov, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov
Sternberg Astronomical Institute, Moscow State University

K.Ivanov, S.Yazev
Irkutsk State University

A. Tlatov, A.V. Parhomenko,
Kislovodsk Solar Station of the Pulkovo Observatory




MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
2x500mm,2 x 4 square degrees, 2 x 16Mpx Apogee CCD) located
at Kourovka Observatory has  observed  FERMI error box

GRB_RA:          313.740d {+20h 54m 58s} (J2000)
GRB_DEC:         +32.350d {+32d 21' 00"} (J2000)

1.18 degres error box radius (Trigg Number 265206153)

starting after sunset (19:18:23.275, ~7 hours after GRB time) with 180s 
exposure in R and V filters simultaniuosly at ~60 degrees zenit distance.


Robot do not detect OT with limit:
  R>19.0 V>18.1

Our images cover 30% last 1 sigma error box (A. von Kienlin, GCN Circ 
9447)


The R-image is available at


http://observ.pereplet.ru/images/GRB090528B/grb090528B.jpeg

The black circle is A. von Kienlin, GCN Circ 9447 error box.
The message may be cited.

mailto: lipunov@sai.msu.ru


GRB_name: GRB090531B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9469
SUBJECT: GRB 090531B: Swift/UVOT Upper Limits
DATE:    09/06/01 10:06:42 GMT
FROM:    Patricia Schady at MSSL/Swift  <ps@mssl.ucl.ac.uk>

P. Schady (MSSL-UCL) and J. R. Cummings (NASA/UMBC) report on behalf of 
the Swift/UVOT team:

The Swift/UVOT observed the field of GRB 090531B starting 3924 s after the 
BAT trigger (Cummings et al., GCN Circ. 9461), once the GRB came out of 
Earth limb observing constraint. No optical afterglow is detected in any 
of the UVOT exposures at the position of the X-ray afterglow (Sbarufatti 
et al., GCN Circ. 9463), with the following three-sigma upper limits:

Filter  T_mid(s)  Exp(s)   3-sig Mag UL

white    3934      74      > 20.52
v        4105      98      > 19.08
b        4926      98      > 20.06
u        4721      98      > 19.74
uvw1     4515      98      > 19.65
uvm2     4310      98      > 19.32
uvw2     5336      98      > 19.61

The values quoted above are not corrected for the large Galactic 
extinction due to the reddening of E(B-V)=1.12 in the direction of the 
burst (Schlegel et al. 1998). The photometry is on the UVOT photometric 
system described in Poole et al. (2008, MNRAS, 383, 627).


GRB_name: GRB090531B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9470
SUBJECT: GRB 090531B, RIMOTS optical upper limits
DATE:    09/06/01 13:32:06 GMT
FROM:    Eri Sonoda at U of Miyazaki/Japan  <sonoda@astro.miyazaki-u.ac.jp>

E. Sonoda, K. Noda, N. Ohmori, K. Kono, H. Hayasi,
A. Daikyuji, Y. Nisioka, M. Yamauchi
(University of Miyazaki)

 We have observed the field covering the error circle of
GRB090531B (Swift trigger 353728, GCN 9461(J. R. Cummings et al.))
with the unfiltered CCD camera on the 30-cm telescope
at University of Miyazaki.
 The observation was started 18:37:28 UT (92 s after the Swift trigger),
under cloudy condition.
First image was obtained at 18:41:05 UT (309 s after the Swift trigger).
 We have compared our data of 30 sec exposures with the USNO-A2.0 catalog.
There is no new source at the reported position.
(GCN 9462(B. E. Schaefer et al.), GCN 9464(C. Gronwall et al.)
 GCN 9465(T. N. Ukwatta et al.), GCN 9469(P. Schady et al.))

 Preliminary analysis shows there is no new source brighter than 14.6 mag.


GRB_name: GRB090531B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9471
SUBJECT: Corrections to GRB 090531B Swift/UVOT Upper Limits
DATE:    09/06/01 14:29:44 GMT
FROM:    Patricia Schady at MSSL/Swift  <ps@mssl.ucl.ac.uk>

P. Schady (MSSL-UCL) and J. R. Cummings (NASA/UMBC) report on behalf of 
the Swift/UVOT team:

We report a mistake in a few of the times provided in GCN 9469, including 
the start time of the observations, which was in fact 3849 s after the BAT 
trigger (Cummings et al., GCN Circ. 9461). Also, the exposure times of the 
UVOT observations should have been two times the values given.

The corrected 3-sigma upper limits for the UVOT observations of the field 
of GRB 090531B are provided below.

Filter T_mid(s)  Exp(s)  3-sig Mag UL

white    3924      147      > 20.52
v        4105      197      > 19.08
b        4926      197      > 20.06
u        4721      197      > 19.74
uvw1     4515      197      > 19.65
uvm2     4310      197      > 19.32
uvw2     5336      197      > 19.61

The values quoted above are not corrected for the large Galactic 
extinction due to the reddening of E(B-V)=1.12 in the direction of the 
burst (Schlegel et al. 1998). The photometry is on the UVOT photometric 
system described in Poole et al. (2008, MNRAS, 383, 627).


GRB_name: GRB090530B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9472
SUBJECT: GRB 090530B: Fermi GBM detection
DATE:    09/06/01 14:56:31 GMT
FROM:    Alexander van der Horst at NASA/MSFC  <Alexander.J.VanDerHorst@nasa.gov>

A.J. van der Horst (NASA/MSFC/ORAU) reports on behalf of the
Fermi GBM Team:

"At 18:14:24.42 UT on 30 May 2009, the Fermi Gamma-ray Burst Monitor
(GBM) triggered and located GRB 090530B (trigger 265400066 / 090530.760).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 73.2, Dec = +13.8 (J2000 degrees, equivalent to
J2000 4h53m, +13d47'), with a statistical uncertainty of less than 1 degree
(radius, 1-sigma containment, statistical only; there is additionally
a systematic error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 84 degrees.

The GBM light curve of this long and soft GRB consists of a double peaked
FRED, with a total duration (T90) of 194 s (8-1000 keV). The time-averaged
spectrum from T0-3.1 to T0+110.6 s is best fit by a Band function with
alpha = -0.71 +/- 0.06, beta = -2.42 +/- 0.05, and Epeak = 67 +/- 3.
The fluence (8-1000 keV) in this interval is (5.9 +/- 0.4)E-5 erg/cm^2.
The 1-sec peak photon flux measured starting from T0+10.2s in the
8-1000 keV band is 10.8 +/- 2.0 ph/s/cm^2.

The spectral and temporal analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090529B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9473
SUBJECT: GRB 090529B: Fermi GBM detection
DATE:    09/06/01 15:04:50 GMT
FROM:    Arne Rau at MPE  <arau@mpe.mpg.de>

Arne Rau (MPE) reports on behalf of the Fermi GBM Team:

"At 07:26:22.41 UT on 29 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090529B (trigger 265274784 / 090529310).

The on-ground calculated location, using the GBM trigger
data, is RA = 231.2, DEC = +32.2 (J2000 degrees,
equivalent to 15 h 25 m, 32 d 12 '), with an uncertainty
of 7.2 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 36 degrees.

The GBM light curve consists of a single peak
with a duration (T90) of about 5.1 s (8-1000 keV).
The time-averaged spectrum from T0-1.792 s to T0+5.376 s is
best fit by a Band function with Epeak = 142 +/- 56 keV,
alpha = -0.7 +/- 0.3, and beta = -2.0 +/- 0.3

(chi squared 561 for 544 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(3.4 +/- 0.9)E-07 erg/cm^2. The 1.28-sec peak photon flux measured
starting from T0+0.003 s in the 8-1000 keV band
is 4.1 +/- 0.1 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090529C
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9474
SUBJECT: GRB 090529C: Fermi GBM detection
DATE:    09/06/01 15:09:17 GMT
FROM:    Arne Rau at MPE  <arau@mpe.mpg.de>

Arne Rau (MPE) reports on behalf of the Fermi GBM Team:

"At 13:32:00.49  UT on 29 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090529C (trigger 265296722 / 090529564).

The on-ground calculated location, using the GBM trigger
data, is RA = 162.7, DEC = 47.3 (J2000 degrees,
equivalent to 10 h 51 m, 47 d 18 '), with an uncertainty
of 1.5 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 69 degrees.

This burst was also independently detected by INTEGRAL SPI-ACS.

The GBM light curve consists of two narrow pulses
with a duration (T90) of about 10.4 s (8-1000 keV).
The time-averaged spectrum from T0-0.002 s to T0+10.048 s is
best fit by a Band function with Epeak = 188 +/- 15 keV,
alpha = -0.84 +/- 0.05, and beta = -2.1 +/- 0.1

(chi squared 795 for 648 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(3.1 +/- 0.1)E-06 erg/cm^2. The 1.028-sec peak photon flux measured
starting from T0+9.024 s in the 8-1000 keV band
is 25 +/- 1 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog.

We further report that the Fermi Observatory executed a maneuver 
following this trigger and tracked the
burst location for the next 5 hours, subject to Earth-angle constraints. "


GRB_name: GRB090531B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9475
SUBJECT: GRB 090531B: Swift/BAT spectral lag results
DATE:    09/06/01 15:55:43 GMT
FROM:    Tilan Ukwatta at GSFC/GWU  <tilan.ukwatta@gmail.com>

T. N. Ukwatta (GWU/GSFC), S. D. Barthelmy (GSFC), J. R. Cummings
(NASA/UMBC), T. Sakamoto (GSFC/UMBC), M. Stamatikos (GSFC/ORAU),
N. Gehrels (GSFC) (for the Swift-BAT team):

For GRB 090531B (Cummings et al. GCN 9461), the BAT team has
analyzed spectral lags for the data from T-1.0 sec to T+2.0 sec
using non-mask weighted light curves with 16 msec time binning.
The spectral lags were measured between standard canonical BAT
energy bands: channel 1 (15-25 keV), 2 (25-50 keV), 3 (50-100 keV)
and 4 (100-350 keV) are given below.

Lag Ch3-Ch2 : -2 +/- 9 msec
Lag Ch4-Ch2 : 11 +/- 5 msec
Lag Ch4-Ch3 :  8 +/- 3 msec

The signal-to-noise ratio in channel 1 is too weak to make a
lag measurement.

These lag values are consistent with lags observed for short
hard burst with extended emission.


GRB_name: GRB090531A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9476
SUBJECT: GRB 090531A: SARA upper limit
DATE:    09/06/01 17:27:55 GMT
FROM:    Adria C. Updike at Clemson U  <aupdike@clemson.edu>

Gary Henson, Shannon Hall, Mark Gorski (ETSU/SARA REU), Adria Updike,
Dieter Hartmann (Clemson University) report:

The 0.9m SARA telescope located at Kitt Peak National Observatory began
imaging the field of GRB 090531A (Stamatikos et al., GCN 9454) about 2.5
hours after the burst under decent weather conditions.  In one hour of
stacked exposures, we detect no new sources down to a limiting magnitude
of R > 20.5 (with respect to the USNO B.1 catalog).  No further
observations are planned.


GRB_name: GRB090529B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9477
SUBJECT: GRB090529B: ROVOR Upper Limits
DATE:    09/06/01 21:51:27 GMT
FROM:    J. Ward Moody at BYU  <rovor.byu@gmail.com>

Richard L. Pearson, Cameron J. Pace and J. Ward Moody report for
Brigham Young Universitys ROVOR team:

We searched for GRB 090529B at the position specified by the Fermi
notice processed at 07:27:20UT on 29 May 2009 (Fermi-GBM Ground
Position notice, trigger 265274784, record 57). The notice reports a
GRB position of 15h 36m 29s +37d 02 22 (J2000) with an error of 9.86
degrees. ROVORs 0.41 m telescope, with a FOV = 10 arcminutes,
centered the frames at 15h 36m 26.924s ( 0.0990 arcseconds) +37d 04
28.748 ( 0.1145 arcseconds, J2000). Rau (GCN Circ. 9473) reports a
ground calculated location of 15h 25m +32d 12 with an uncertainty of
7.2 degrees. Our images are well within the degree of uncertainty
reported by the Fermi trigger and within 1.9 degrees from the
specified location in GCN Circ. 9473.

ROVOR began retrieving data at 08:51:06.4UT (1.15 hrs post-burst). 25
x 60s frames were taken in the R band and 10 x 60s frames were taken
in the V band. No optical afterglow was located after stacking the
images and comparing them to the STScI Digital Sky Survey image of the
same field. By using calibration stars from the nearby field of Mrk
501 (16h 53m 52.13s +39d 45 36.2, J2000), limiting magnitudes of V >
20.7  0.1mag and R > 21.4  0.1mag were found.


GRB_name: GRB090530A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9478
SUBJECT: GRB 090530: Early RAPTOR Optical Observations
DATE:    09/06/02 00:37:08 GMT
FROM:    James Wren at LANL  <jwren@nis.lanl.gov>

J. Wren, W.T. Vestrand, P.R. Wozniak, H. Davis, B. Norman
of Los Alamos National Laboratory report:

The RAPTOR telescope system responded to Swift trigger
353567 (Cannizzo et al., GCN 9438) under fair observing conditions.
Our narrow-field instruments began observing the location at
03:18:37.96 UTC, 19.6 s after the Swift trigger.  We detect the
optical counterpart initially reported by Cannizzo et al. (GCN 9438)
and Flewelling et al. (GCN 9439).  Our first image at T+22.1 seconds
shows the counterpart at R~17.1.  It appears to brighten over the
next minute reaching a peak near R~16.3 and then begins fading in
the manner described by Schady et al. (GCN 9450) and Rossi et al.
(GCN 9458).  Our unfiltered images were calibrated against the
USNO-B1 R-band.  The following table gives selected observations,
not corrected for extinction, from this event.

t-mid(s)    exp(s)     mag     mag-err
--------------------------------------------
22.08        5.0      17.13    0.25
57.90        5.0      16.30    0.10
84.50        5.0      16.60    0.13
133.21      10.0      16.87    0.11
414.65      30.0      17.31    0.09


GRB_name: GRB090528B
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9479
SUBJECT: GRB 090528B: Suzaku WAM observation of the prompt emission 
DATE:    09/06/02 11:09:48 GMT
FROM:    Yoshitaka Hanabata at Hiroshima U  <hanabata@hep01.hepl.hiroshima-u.ac.jp>

Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa (Hiroshima U.),
K. Kono, E. Sonoda, M. Yamauchi, N. Ohmori, H. Hayashi,
K. Noda, A. Daikyuji, Y. Nishioka (Univ. of Miyazaki),
M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA),
W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda,
T. Sugasahara (Saitama U.), Y. Urata (NCU),
T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo),
K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y. E. Nakagawa,
T. Tamagawa (RIKEN), S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.),
on behalf of the Suzaku WAM team, report:

The long GRB 090528B (Fermi-GBM trigger 265206153 / 090528516;
von Kienlin et al., GCN9447) triggered the Suzaku Wide-band All-sky
Monitor (WAM) which covers an energy range of 50 keV - 5 MeV
at 12:22:29.849 UT (=T0).

The observed light curve shows a bright multi-peaked structure
starting at T0-5 s, ending at T0+60 s, and very weak emission is seen
up to T0+120 s. The total T90 duration is about 77 seconds.

The fluence in 100 - 1000 keV was 3.08 (-0.16, +0.14) x10^-5 erg/cm2.
The 1-s peak flux measured from T0+11s was 3.53 (-0.32, +0.27)
photons/cm2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0-5 s
to T0+120 s is fitted by a single power-law with a photon index of
2.00 (-0.10, +0.11) (chi^2/d.o.f = 32.1/20).

The light curves for this burst will be available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html


GRB_name: GRB090531B
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9480
SUBJECT: GRB 090531B: GROND observation
DATE:    09/06/02 11:58:24 GMT
FROM:    Jochen Greiner at MPI  <jcg@mpe.mpg.de>

A. Rossi (Tautenburg), F. Olivares, T. Kruehler and J. Greiner (all
MPE Garching) report on behalf of the GROND team:

We observed the field of GRB 090531B (Swift trigger 353728, Cummings et al. 
2009, GCN #9461) simultaneously in g'r'i'z'JHK with GROND 
(Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPI/ESO telescope 
at La Silla Observatory (Chile).

Observations started on 1 June 2009 at 00:03 UT, 5.5 hours after the burst and 
continued until 00:50 UT under mediocre seeing (~1.5), cirrus and Moon light.
A second epoch started at 04:33 UT under better conditions, consisting of 
72 min exposure in g'r'i'z' and 60 min in JHK.

We find three objects within the XRT error circle (Sbaruffatti et al. 2009,
GCN #9463), and another three at the outer circumference of the error circle
(see finding chart on http://www.mpe.mpg.de/~jcg/grb090531B.html). Within
+-0.2 mag, none of these objects shows any variability between 5.5 and 10 hrs 
post-burst, and thus are most likely foreground objects.

In empty regions of the error circle, the first epoch yields the following 
upper limits (all AB):

g' > 22.9
r' > 22.6
i' > 22.1
z' > 22.8
J  > 20.1
H  > 19.8
K  > 19.2

which were obtained using the USNO and 2MASS field stars as reference.
However, given the poor conditions and preliminary photometric calibration,
a variable object might be hidden behind one of the foreground objects,
and masked in the difference image due to the distorted PSF from the first
epoch. In that case, the upper limits would be about 2 mag brighter.
No correction has been applied for the strong foreground reddening of
E(B-V)=1.11 mag (Schlegel et al. 1998).


GRB_name: GRB090531B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9481
SUBJECT: GRB 090531b, SMARTS optical/IR observations
DATE:    09/06/02 21:50:32 GMT
FROM:    Bethany Cobb at UC Berkeley  <bcobb@astro.berkeley.edu>

B. E. Cobb (UC Berkeley) reports:

Using the ANDICAM instrument on the 1.3m telescope at CTIO, we obtained
optical/IR imaging of the error region of GRB 090531b (GCN 9461, Cummings
et al.) over two epochs with mid-exposure times of 2009-06-01 02:56 UT
and 2009-06-02 05:26 UT (8.3 and 34.8 hours post-burst). Total summed 
exposure times for each observation amounted to 36 minutes in R and
30 minutes in J.

While there are a number of sources in and around the position of
the GRB X-ray afterglow (GCN 9463, Sbarufatti et al.; GCN 9480, Rossi
et al.), image differencing of the two epochs using the ISIS image
subtraction program does not reveal any significant variable source.  The
sky limiting magnitude of the images is I>21.1 and J>18.5 (where optical
photometry is calibrated using USNO-B1 stars and IR photometry with 2MASS;
these limits have not been corrected for Galactic reddening).


GRB_name: GRB090529A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9482
SUBJECT: GRB090529: Further NOT optical observations
DATE:    09/06/02 21:57:20 GMT
FROM:    Dong Xu at DARK,NBI  <dong@astro.ku.dk>

D. Xu, G. Leloudas, D. Malesani, J. P. U. Fynbo, J. Maund (DARK/NBI), P. 
Jakobsson (Univ. Iceland), and T. Liimets (NOT & Tartu Obs.) report on 
behalf of a larger collaboration:

We continued to observe the field of GRB 090529 (Sakamoto et al., GCN 
9430) with the Nordic Optical Telescope equipped with ALFOSC.  We 
obtained 3x600 s R-band frames staring on June 01, 21:26:31 UT and 
ending on June 01, 22:00:52 UT. The mid-exposure time is 3.31 days after 
the burst.

The optical afterglow (Xin et al., GCN 9431; Schady et al., GCN 9435) is 
still detected in the stacked frame. Using the same reference star as in 
  Kann et al. (GCN 9436) and in Leloudas et al. (GCN 9453), we obtain 
R=22.8+/-0.1 for the afterglow.

Measurements by Kann et al. (0.3 day after the burst) and Leloudas et 
al. (1.29 days after the burst) indicate an optical power-law decay 
index of alpha1=0.72. Our new observation indicates that the optical 
decay became even slower, with an index of alpha2=0.3 between our two 
obs epochs. In contrast, during the whole period of 0.3 - 3.31 days the 
X-ray afterglow decays with the index of ~1.0 (ref, Evans et al. 2009). 
The slow optical decay may be also due to the presence of a fairly 
bright host galaxy.

Further optical observations are encouraged.


GRB_name: GRB090528A
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9483
SUBJECT: GRB 090528: Suzaku WAM observation of the prompt emission
DATE:    09/06/03 01:55:34 GMT
FROM:    Yujin E. Nakagawa at RIKEN  <yujin@crab.riken.jp>

Y. E. Nakagawa, T. Tamagawa (RIKEN), K. Yamaoka, S. Sugita (Aoyama Gakuin U.),
T. Uehara, Y. Hanabata, T. Takahashi, Y. Fukazawa (Hiroshima U.), M. Ohno,
M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA), K. Kono, E. Sonoda, M. Yamauchi,
N. Ohmori, H. Hayashi, K. Noda, A. Daikyuji, Y. Nishioka (Univ. of Miyazaki),
W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda, T. Sugasahara (Saitama U.),
Y. Urata (NCU), T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo),
S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.), on behalf of the Suzaku WAM team,
report:

The long GRB 090528 (Fermi/GBM trigger 265176543 / 090528173, von Kienlin et al.,
GCN 9446) was detected by the Suzaku Wide-band All-sky Monitor (WAM) which
covers an energy range of 50 keV - 5 MeV at 04:09:01.00 UT (=T0). The observed
light curve shows a single-peaked structure lasting from T0-8s, ending at T0+28s,
with a duration (T90) of about 26.0 seconds. 

The fluence in 100 - 1000 keV was 1.9 (+0.2/-0.7) * 10^-6 erg/cm^2.
The 1-s peak flux measured from T0+2.5s was 0.5 (+0.2/-0.3) photons/cm^2/s
in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0-4s to T0+22s
is well fitted by a single power-law with a photon index of 2.6 (+0.7/-0.5)
(chi^2/d.o.f = 13/13). All the quoted errors are at statistical 90% confidence
level, in which the systematic uncertainties are not included.

The light curves for this burst are available at:

 http://www.astro.isas.ac.jp/suzaku/research/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html


GRB_name: GRB090424A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9484
SUBJECT: GMRT observation of GRB 090424 afterglow
DATE:    09/06/03 14:37:33 GMT
FROM:    Atish Kamble at U. of Amsterdam  <A.P.Kamble@uva.nl>

Atish Kamble (University of Amsterdam), Sabyasachi Pal (NCRA/TIFR),
A. J. van der Horst (NASA/MSFC), D. Bhattacharya (IUCAA,Pune),
R. Wijers (University of Amsterdam), C. H. Ishwara Chandra
(NCRA/TIFR), Evert Rol (University of Amsterdam) report on behalf
of a larger GRB collaboration :

The Giant Metrewave Radio Telescope (GMRT), India observed the field of
GRB090424 (GCN 9223, GCN 9260) on 23 May 2009 (between 11.0 UT
and 15.0 UT i.e. about 30 days after the burst) at 1280 MHz using a
bandwidth of 32 MHz. The radio transient was not detected down
to a 3-sigma upper limit of 141 microJy at the source location.

We thank the GMRT and the National Centre for Radio Astrophysics (NCRA)
staff. This TOO was done under the GMRT Director's Discretionary Time.
GMRT is run by NCRA-TIFR, Pune (INDIA).

This message may be cited.


GRB_name: GRB090529A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9485
SUBJECT: GRB 090529A: RTT150 Optical Observations
DATE:    09/06/03 15:51:34 GMT
FROM:    Solen Balman at METU  <solen@astroa.physics.metu.edu.tr>

S. Balman (METU), M. Parmaksizoglu (TUG)
Z. Eker (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.)
I. Bikmaev, N. Sakhibullin (KSU/AST)
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI),

report:

We observed the field of GRB090529A (trigger=353540, Sakamato et al. 2009
GCN Circ. 9430, also GCN Circ. 9431-9436,9448,9449,9457) with the 
Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe, TUBITAK National 
Observatory, Turkey) on 30 May  starting at 00:09:01.86 UT about 9.94 hours 
(0.414 d) after the burst
using the TFOSC CCD (burst detected at 14:12:35 UT with Swift Burst Alert 
Telescope (BAT)).

We obtained one 900 sec exposure using the  R band  filter (Bessell filter). We 
found the afterglow candidate at the location designated by the Swift XRT 
position given by Osborne et al. 2009 GCN Circ. 9433. We performed PSF 
photometry using DAOPHOT within MIDAS software on the 13.3 by 13.3 arcmin field 
around the afterglow candidate. We calibrated the R band magnitude
using the same  USNO-B1 reference star noted by Kann et al. 2009 GCN Circ. 
9436. The GRB090529 afterglow candidate is detected at R = 21.2+/-0.2 mag.

This message can be cited.

[GCN OPS NOTE(03jun09):  Per author's request, the Subject line was changed.]


GRB_name: GRB090602A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9486
SUBJECT: GRB 090602: Fermi GBM detection
DATE:    09/06/03 16:38:59 GMT
FROM:    Elisabetta Bissaldi at MPE  <ebs@mpe.mpg.de>

Elisabetta Bissaldi (MPE) reports on behalf of the Fermi GBM Team:


"At 13:32:22.85 UT on 02 June 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090602 (trigger 265642344 / 090602564).
The on-ground calculated location, using the GBM trigger
data, is RA =  248.9, DEC = -65.0 (J2000 degrees,
equivalent to 16h 36m, -65d 00'), with an uncertainty
of 3.4 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).

The angle from the Fermi LAT boresight is 112 degrees.

This burst was also independently detected by INTEGRAL SPI-ACS.

The GBM light curve consists of a broad single peak
with a duration (T90) of about 16 s (8-1000 keV).
The time-averaged spectrum from T0-1.3s to T0+9s is
best fit by a power law function with an exponential
high energy cutoff. The power law index is -0.56 +/- 0.14 and
the cutoff energy, parameterized as Epeak, is 503 +/- 91 keV
(chi squared 327 for 358 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(5.7 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+2.8 s in the 8-1000 keV band
is 3.62 +/- 0.17 ph/s/cm^2.


The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090530A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9487
SUBJECT: GRB 090530: RTT150 Optical Observation
DATE:    09/06/03 17:47:25 GMT
FROM:    Solen Balman at METU  <solen@astroa.physics.metu.edu.tr>

S. Balman (METU), M. Parmaksizoglu (TUG)
Z. Eker (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.)
I. Bikmaev, N. Sakhibullin (KSU/AST)
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI),

report:

We observed the field of GRB 090530 (Swift trigger=353567, 
Cannizzo et al.,2009 GCN Circ. 9438) with the Russian-Turkish 1.5-m telescope
(RTT150, Bakirlitepe, TUBITAK National Observatory, Turkey) on
30 May  starting at 18:30:37.7 UT about 15.2 hours (0.633 d) after the burst 
using the TFOSC CCD (burst detected at 03:18:18 UT with Swift Burst Alert 
Telescope(BAT)).

Flewelling et al. 2009 GCN Circ. 9439 found the afterglow at
16.0 mag at 03:18:42.7 UT. Calibrating the data against the USNO star at
RA = 11:57:41.7, Dec = +26:35:43, Rossi et al. 2009 GCN Circ. 9458
obtain R = (22.2 +-0.2) mag 21.3 hrs after burst. They also found a
  break in the optical light at around 22 ksec post-burst (see also 
GCN Circ.9440-9443, 9450-9452, 959, 9466, 9478 for white light
and UV photometry).

We obtained one 900 sec exposure using the  R band  filter (Bessell filter).
We used the Swift XRT position derived by Breadmore at al. (2009) 
GCN Circ. 9445 to locate the afterglow candidate. We were able see the 
source, but unable to calculate a magnitude using PSF photometry with
DAOPHOT within MIDAS software performed on the 13.3 by 13.3 arcmin field 
around the candidate. We find a frame upper limit of R = 21.1+/-0.5 mag
at 3 sigma and 21.9+/-0.5 mag at 2 sigma confidence level 
calculated using the same  USNO star mentioned in the above paragraph.


This message can be cited.


GRB_name: GRB090530A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9488
SUBJECT: GRB 090530: Further NOT optical observations
DATE:    09/06/03 19:51:39 GMT
FROM:    Dong Xu at DARK,NBI  <dong@astro.ku.dk>

D. Xu, G. Leloudas, D. Malesani, J. P. U. Fynbo, J. Hjorth (DARK/NBI), 
P.  Jakobsson (Univ. Iceland), and T. Liimets (NOT & Tartu Obs.) report 
on behalf of a larger collaboration:

We continued to observe the field of GRB 090530 (Cannizzo et al., GCN 
9438) with the Nordic Optical Telescope equipped with ALFOSC.  We 
obtained 3x600 s R-band frames staring on June 01, 22:04:19 UT, 66.7669 
hr after the burst.

The optical afterglow (Cannizzo et al., GCN 9438) is still detected in 
the stacked frame. The magnitude is R=22.6+/-0.2 against the same 
reference star in Malesani et al. (GCN 9452).

Balman et al. (GCN 9487) found a 3sigma upper limit of R=21.1+/-0.5 mag 
at 15.2 hr after the burst. Our first observation shows R=21.6 mag at 
17.8 hr after the burst. Rossi et al. (GCN 9458) found R=22.2+/-0.2 mag 
at 21.3 hr after the burst, and a break in the light curve at around 22 
ksec post-burst with slopes of 0.5+-0.1 (pre-break) and 1.8+-0.4 
(post-break), using previous obs (Flewelling et al., GCN 9439; Schady et 
al., GCN 9450; Nissinen & Hentunen, GCN 9442). Our new observation 
indicates that the optical decay is becoming much slower. The slower 
optical decay may be due to the presence of a fairly bright host galaxy.

Further optical observations are encouraged.


GRB_name: GRB090530B
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9489
SUBJECT: GRB 090530B: Suzaku WAM observation of the prompt emission
DATE:    09/06/04 11:05:56 GMT
FROM:    Kazuhiro Noda at Miyazaki U  <kaz1206@astro.miyazaki-u.ac.jp>

K. Noda, E. Sonoda, M. Yamauchi, N. Ohmori, H. Hayashi,
K. Kono, A. Daikyuji, Y. Nishioka (Univ. of Miyazaki),
Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa (Hiroshima U.),
M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA),
W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda,
T. Sugasahara (Saitama U.), Y. Urata (NCU),
T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo),
K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y. E. Nakagawa,
T. Tamagawa (RIKEN), S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.),
on behalf of the Suzaku WAM team, report:

The long GRB 090530B (Fermi/GBM trigger #265400066 / 090530.760;
van der Horst et al., GCN 9472)

was detected by the the Suzaku Wide-band All-sky Monitor (WAM) which
covers an energy range of 50 keV - 5 MeV at 18:14:23 UT (=T0).

The observed light curve shows a single peak
starting at T0-1s, ending at T0+219s,
with a duration (T90) of about 113 seconds.
The fluence in 100 - 1000 keV was 2.41 ( +0.06/ -0.07 )x10-5 erg/cm2.
The 1-s peak flux measured from T0+8s was 2.39 ( +0.08/ -1.41 )
photons/cm2/s
in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0-1s to
T0+219s is well fitted by a single power-law with a photon index
of 3.30 ( +0.14/ -0.13 ) (chi2/d.o.f = 31/17 ).

All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.

The light curves with 1-sec time resolution for this burst will be
appeared at:

http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html


GRB_name: GRB090607A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9491
SUBJECT: GRB 090607: Swift detection of a burst
DATE:    09/06/07 06:11:45 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), M. M. Chester (PSU),
C. Guidorzi (U Ferrara), H. A. Krimm (CRESST/GSFC/USRA),
K. L. Page (U Leicester), D. M. Palmer (LANL),
T. N. Ukwatta (GSFC/GWU) and H. Ziaeepour (UCL-MSSL) report on behalf
of the Swift Team:

At 05:30:17 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090607 (trigger=354299).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 191.209, +44.130 which is 
   RA(J2000)  = 12h 44m 50s
   Dec(J2000) = +44d 07' 47"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows several spikes
with a duration of about 5 sec.  The peak count rate
was ~4000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 05:31:27 UT, 70 seconds
after the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source located at RA, Dec 191.16903, 44.10541 which
is equivalent to:
   RA(J2000)  = 12h 44m 40.57s
   Dec(J2000) = +44d 06' 19.5"
with an uncertainty of 3.9 arcseconds (radius, 90% containment). This
location is 136 arcseconds from the BAT onboard position, within the
BAT error circle. This position may be improved as more data are
received; the latest position is available at
http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (1.84e+20
cm^-2, Kalberla et al. 2005), with an excess column of 4.1
(+2.44/-2.19) x 10^21 cm^-2 (90% confidence). 

Because of the presence of a magnitude 6.3 star in the UVOT
Field of View, 2.3 arcmin from the XRT location, 
UVOT will not be able to observe this burst. 

There was some extra delay in processing this burst.  It was originally
a subthreshold trigger (Image_signif=6.49 sigma).  The automated processing
for the XRT position had a problem.  This circular is based on manual processing. 

Burst Advocate for this burst is F. E. Marshall (marshall AT milkyway.gsfc.nasa.gov). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090607A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9492
SUBJECT: GRB 090607: Faulkes Telescope North observations
DATE:    09/06/07 08:18:10 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi (U. Ferrara), A. Melandri (Liverpool JMU), P. O'Brien,
N. Tanvir (U. Leicester) on behalf of a large collaboration report:

On 2009 June 07 at 06:01:12 UT we observed the Swift-BAT GRB 090607
(Marshall et al., GCN Circ. 9491) with the 2-m Faulkes Telescope North.

Observations started 31 minutes after the BAT trigger time and were
performed using the B, V, R and i' filters. We could not find any
uncatalogued object inside the XRT error circle down to the following
limiting magnitudes:

Time Interval   Total Exp  Filter     Limit
(min from GRB)  (s)                  (mag)
-------------------------------------------
31 - 82          720        R        > 21.8
35 - 75          520        i'       > 21.6
-------------------------------------------

Magnitudes in the R and i' filters have been calibrated against
nearby field stars using USNOB1-R2 and SDSS-i catalogue values,
respectively.


GRB_name: GRB090607A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9493
SUBJECT: GRB 090607: GRAS001 optical observations
DATE:    09/06/07 09:00:11 GMT
FROM:    Veli-Pekka Hentunen at Taurus Hill Obs,A95  <veli-pekka.hentunen@kassiopeia.net>

Markku Nissinen (Taurus Hill Observatory) and Veli-Pekka Hentunen (Taurus
Hill Observatory) report:

We used Global-rent-a-scope GRAS001 Tak Mewlon 0.30m telescope with FLI 
IMG1024 Dream Machine at RAS Observatory Mayhill H06 (New Mexico, USA) 
for follow-up observations of GRB090607 (F. E. Marshall et al., GCN 9491).
The observations were started on June 7, at 06:11 UTC (1.0 hours after the
burst) and stopped on June 7, at 07:12 UTC. Three unfiltered 120s and two
unfiltered 600s images were taken. We did not find any new object in the
XRT error circle. Upper limit for the observations is >18.5 mag (3UL).
Quoted upper limit has been derived using POSSII J and USNO-B1.0 field 
stars as reference.

Filter          Tmid(s)       Exp(s)     Mag (CR) USNO-B1.0

unfiltered         07:01:32      2x600      >18.5


GRB_name: GRB090607A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9494
SUBJECT: GRB 090607: Swift-BAT refined analysis of the SHB
DATE:    09/06/07 11:32:02 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC/UMD), F. E. Marshall (NASA/GSFC) D. M. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090607 (trigger #354299)
(Marshall, et al., GCN Circ. 9491).  The BAT ground-calculated position is
RA, Dec = 191.194, 44.108 deg, which is 
   RA(J2000)  =  12h 44m 46.7s 
   Dec(J2000) = +44d 06' 28.4" 
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 96%.
 
The mask-weighted light curve shows two narrow peaks.  The first starts
at T-0.1 sec, peaks at T+0.1 sec, and ends at T+0.7sec.  The second peak
starts at ~T+1.7 sec, peaks at T+2.2 sec, and ends at T+2.5 sec.  There is
no hint of emission out to at least T+243 sec.  T90 (15-350 keV) is
2.3 +- 0.1 sec (estimated error including systematics).
 
The time-averaged spectrum from T+0.1 to T+2.5 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.25 +- 0.30.  The fluence in the 15-150 keV band is 1.1 +- 0.2 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.01 sec in the 15-150 keV band
is 0.7 +- 0.1 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 

Based on the shortness of the duration and the spectral hardness, we believe
this to be a short hard burst.
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/354299/BA/


GRB_name: GRB090607A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9495
SUBJECT: GRB 090607: Swift/UVOT Upper Limits
DATE:    09/06/07 16:42:02 GMT
FROM:    Peter Curran at MSSL  <pac@mssl.ucl.ac.uk>

P.A. Curran (UCL-MSSL) and F. Marshall (NASA/GSFC)
report on behalf of the Swift/UVOT team:


The Swift/UVOT began settled observations of the field of GRB 090607
75 s after the BAT trigger (Marshall et al., GCN Circ. 9491). No optical 
afterglow consistent with the XRT position (Marshall et al., GCN Circ. 
9491) is detected in the initial UVOT exposures. Preliminary 3-sigma 
upper limits using the UVOT photometric system (Poole et al. 2008, 
MNRAS, 383, 627) for the first finding chart (FC) exposure and 
subsequent exposures are:


Filter         T_start(s)  T_stop(s)   Exp(s)       Mag

uvw1           12715       13943       1209         >20.8
u              75          1233        1140         >21.2
v              11448       12707       1239         >20.4


The values quoted above are not corrected for the Galactic extinction 
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB090607A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9496
SUBJECT: GRB 090607: XRT Team Refined Analysis
DATE:    09/06/07 18:39:42 GMT
FROM:    Kim Page at U.of Leicester  <kpa@star.le.ac.uk>

K.L. Page, A.P. Beardmore, P.A. Evans (U. Leicester) & F.E. Marshall 
(NASA/GSFC) report on behalf of the Swift-XRT team:

We have analysed the four orbits of XRT data obtained for GRB 090607 
(Marshall et al., GCN Circ. 9491), comprising 108 s of Windowed Timing 
(WT) mode and 9.5 ks of Photon Counting (PC) mode. The refined XRT 
position is RA, Dec = 191.16914, 44.10503, which is equivalent to

RA (J2000) =  12 44 40.59 
Dec(J2000) = +44 06 18.10

with an uncertainty of 3.7 arcsec (radius, 90% containment).

The X-ray light-curve initially brightens slightly, with a power-law of 
alpha = -0.8 +/- 0.5 until 150 +10/-8 s, at which point the afterglow 
starts to decay with alpha = 5.6 +0.5/-0.3. Between ~200 and 400 s after 
the trigger there is a deviation from the decay in the form of a flare. 
The afterglow is no longer detected after the end of the first orbit of 
data (~2365 s after the trigger).

The WT data show a softening trend with time. A spectrum formed from the 
PC mode data from the first orbit can be fitted with a power-law of photon 
index Gamma = 1.88 +/- 0.21, absorbed by the Galactic column of 1.8x10^20 
cm^-2. The observed (unabsorbed) 0.3-10 keV flux over this time is 
5.5x10^-12 (5.8x10^-12) erg cm^-2 s^-1, which corresponds to a counts to 
observed (unabsorbed) flux conversion factor of 3.9x10^-11 (4.1x10^-11) 
erg cm^-2 count^-1.

Because of the lack of detection after the first orbit of data, we cannot 
sensibly predict the future count rate.

The results of the XRT-team automatic analysis are available at 
http://www.swift.ac.uk/xrt_products/00354299.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090606A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9497
SUBJECT: GRB 090606: Fermi GBM detection
DATE:    09/06/08 15:17:29 GMT
FROM:    Elisabetta Bissaldi at MPE  <ebs@mpe.mpg.de>

Elisabetta Bissaldi (MPE) reports on behalf of the Fermi GBM Team: 


"At 11:18:08.00 UT on 06 June 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090606 (trigger 265979890 / 090606471).
The on-ground calculated location, using the GBM trigger
data, is RA =  146.9, DEC = -70.5  (J2000 degrees,
equivalent to 09h 48m, -70d 30'), with an uncertainty
of 5.6 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 128 degrees.

The GBM light curve shows a long, weak pulse
with a duration (T90) of about 60 s (8-1000 keV).
The time-averaged spectrum from T0-5.1 s to T0+12.3 s
is adequately fit by a simple power law function with
index -1.63 +/- 0.09 (chi squared 243 for 237 d.o.f.).
The event fluence (8-1000 keV) in this time interval is
(3.19 +/- 0.16)E-06 erg/cm^2. The 1-sec peak photon flux
measured starting from T0+8 s in the 8-1000 keV band
is 2.41 +/- 0.17 ph/s/cm^2.


The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090608A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9498
SUBJECT: GRB 090608: Fermi GBM detection
DATE:    09/06/09 04:21:53 GMT
FROM:    Alexander van der Horst at NASA/MSFC  <Alexander.J.VanDerHorst@nasa.gov>

A.J. van der Horst (NASA/MSFC/ORAU) reports on behalf of the
Fermi GBM Team:

"At 01:15:26.60 UT on 8 June 2009, the Fermi Gamma-ray Burst Monitor
(GBM) triggered and located GRB 090608 (trigger 266116528 / 090608.052).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 100.2, Dec = -37.4 (J2000 degrees, equivalent to
J2000 6h41m, -37d25'), with a statistical uncertainty of 4.5 degrees
(radius, 1-sigma containment, statistical only; there is additionally
a systematic error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 93 degrees.

The GBM light curve of this long and soft GRB consists of multiple peaks
and has a duration (T90) of 61 s (8-1000 keV). The time-averaged
spectrum from T0-18.4 to T0+20.5 s is adequately fit by a power law with
index = -1.83 +/- 0.07.
The fluence (8-1000 keV) in this interval is (3.2 +/- 0.1)E-6 erg/cm^2.
The 1-sec peak photon flux measured starting from T0+2.1s in the
8-1000 keV band is 2.7 +/- 0.1 ph/s/cm^2.

The spectral and temporal analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090531B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9501
SUBJECT: GRB 090531B: Fermi GBM detection
DATE:    09/06/10 01:07:56 GMT
FROM:    Sylvain Guiriec at UAH  <sylvain.guiriec@lpta.in2p3.fr>

S. Guiriec (UAH)
reports on behalf of the Fermi GBM Team:

"At 18:35:56.49 UT on 31 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090531B (trigger 265487758 / 090531775)
which was also detected by the SWIFT-BAT (Cummings et al. 2008, GCN 9461).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight is 25 degrees.

The GBM light curve consists of a single peak with a duration (T90) of
about 2 s (8-1000 keV).
The time-averaged spectrum from T0-0.23 s to T0+0.77 s is
adequately fit by a Band function with Epeak = 2166(+675-408) keV,
alpha = -0.71(+0.10-0.10), and beta = -2.47(+0.25-0.46)
(Castor C-Stat 780 for 602 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(6.20 +/- 0.18)E-07 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.23 s in the 8-1000 keV band is 1.49 +/- 0.04 ph/s/cm^2.

The spectral and temporal analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090423A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9503
SUBJECT: GRB 090423: WSRT Radio Observations
DATE:    09/06/11 23:45:46 GMT
FROM:    Alexander van der Horst at NASA/MSFC  <Alexander.J.VanDerHorst@nasa.gov>

A.J. van der Horst (NASA/MSFC/ORAU) reports on behalf of a large
collaboration:

"We observed the position of the high redshift GRB 090423 afterglow
at 4.9 GHz with the Westerbork Synthesis Radio Telescope at May 22
11.47 UT to 23.46 UT, i.e. 29.15 - 29.65 days after the burst (GCN 9198).
We do not detect a radio source at the position of the infrared counterpart
(GCN 9202). The three-sigma rms noise in the map around that position is
75 microJy per beam. The formal flux measurement for a point source at the
position of the optical counterpart is 44 +/- 25 microJy.

We would like to thank the WSRT staff for scheduling and obtaining these
observations."


GRB_name: GRB090424A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9504
SUBJECT: GRB 090424: WSRT Radio Observations
DATE:    09/06/12 04:00:08 GMT
FROM:    Alexander van der Horst at NASA/MSFC  <Alexander.J.VanDerHorst@nasa.gov>

A.J. van der Horst (NASA/MSFC/ORAU) and A.P. Kamble (University of
Amsterdam) report on behalf of a large collaboration:

"We observed the position of the GRB 090424 afterglow with the Westerbork
Synthesis Radio Telescope at 2.3 GHz at May 4 19.91 UT to May 5 3.34 UT,
and at 4.9 GHz at May 23 15.97 to 21.45 UT, i.e. 10.39 and 29.19 days
after the burst (GCN 9223) respectively.
We do not detect a radio source at the position of the optical counterpart
(GCN 9223). The three-sigma rms noise in the map around that position is
168 microJy per beam at 2.3 GHz and 132 microJy per beam at 4.9 GHz. The
formal flux measurement for a point source at the position of the optical
counterpart is 47 +/- 56 microJy and 84 +/- 43 microJy at 2.3 and 4.9 GHz
respectively.

We would like to thank the WSRT staff for scheduling and obtaining these
observations."


GRB_name: GRB090602A
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9505
SUBJECT: GRB 090602: Suzaku WAM observation of the prompt emission
DATE:    09/06/12 09:32:39 GMT
FROM:    Norisuke Ohmori at Miyazaki U  <ohmori@astro.miyazaki-u.ac.jp>

N. Ohmori, E. Sonoda, K. Kono, H. Hayashi, K. Noda, A. Daikyuji, 
Y. Nishioka, M. Yamauchi (Univ. of Miyazaki),
M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA),
K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y. E. Nakagawa,
T. Tamagawa (RIKEN), S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.),
Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa (Hiroshima U.),
W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda,
T. Sugasahara (Saitama U.), Y. Urata (NCU),
T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo),
on behalf of the Suzaku WAM team, report:

The long GRB 090602 (Fermi-GBM trigger 265642344 / 090602564;
Bissaldi et al., GCN9486) triggered the Suzaku Wide-band All-sky 
Monitor (WAM) which covers an energy range of 50 keV - 5 MeV
at 13:32:23.291 UT (=T0).

The observed light curve shows a bright multi-peaked structure
starting at T0-1 s, ending at T0+12 s. 
The total T90 duration is about 10 seconds.

The fluence in 100 - 1000 keV was 3.7 (-1.6, +0.4) x10-6 erg/cm2.
The 1-s peak flux measured from T0+3s was 1.0 (-0.7, +0.3)
photons/cm2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from
T0-1s to T0+11s is well fitted by a power-law with exponential cutoff model:
  dN/dE ~  E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
  alpha       0.79(-0.79, +0.95), and
  Epeak        581(+954,-195) keV (chi2/d.o.f. = 52.9/45).

All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.

The light curves for this burst is available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html


GRB_name: GRB090610A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9507
SUBJECT: GRB 090610: Fermi GBM detection
DATE:    09/06/12 16:27:36 GMT
FROM:    Adam Goldstein at Fermi-GBM/UAH  <adam.m.goldstein@msfc.nasa.gov>

A. Goldstein (UAH) reports on behalf of the Fermi GBM Team: 

"At 15:33:25.94 UT on 10 June 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090610 (trigger 266340807 / 090610648).

The on-ground calculated location, using the GBM trigger 
data, is RA = 84.2, DEC = 35.4 (J2000 degrees, 
equivalent to 05h 37m, 35d 224'), with an uncertainty 
of 5.2 degrees (radius, 1-sigma containment, 
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 70 degrees.

This burst was also independently detected by INTEGRAL SPI-ACS.

The GBM light curve consists of one main pulse
with a duration (T90) of about 6.5 s (8-1000 keV). 
The time-averaged spectrum from T0-3.1 s to T0+3.2 s is 
best fit by a simple power law function with index -1.30 +/- 0.03
(chi squared 621.1 for 606 d.o.f.).

The event fluence (8-1000 keV) in this time interval is 
(7.32 +/- 0.24)E-07 erg/cm^2. The 1-sec peak photon flux measured 
starting from T0-0.51 s in the 8-1000 keV band 
is 0.94 +/- 0.09 ph/s/cm^2.

The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090610B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9508
SUBJECT: GRB 090610B: Fermi GBM detection
DATE:    09/06/12 16:28:34 GMT
FROM:    Adam Goldstein at Fermi-GBM/UAH  <adam.m.goldstein@msfc.nasa.gov>

A. Goldstein (UAH) reports on behalf of the Fermi GBM Team: 

"At 17:21:31.90 UT on 10 June 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090610B (trigger 266347293 / 090610723).

The on-ground calculated location, using the GBM trigger 
data, is RA = 276.0, DEC = -42.1 (J2000 degrees, 
equivalent to 18h 24m, -42d 06'), with an uncertainty 
of 9.5 degrees (radius, 1-sigma containment, 
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 91 degrees.

The GBM light curve consists of a single short pulse at trigger time
followed by a broad pulse starting at T0+80 s with a total duration 
(T90) of about 202.5 s (8-1000 keV). 

The time-averaged spectrum for the first pulse from T0-6.2 s to 
T0+4.1 s is best fit by a power law function with an exponential
high energy cutoff.  The power law index is -0.46 +/- 0.36 and
the cutoff energy, parameterized as Epeak, is 104.90 +/- 16.70 keV
(chi squared 338.8 for 359 d.o.f.).

The time-averaged spectrum for the second pulse from T0+79.9 s to
T0+161.8 s is best fit by a simple power law function with index
-1.66 +/- 0.07 (chi squared 454.9 for 360 d.o.f.).

The event fluence (8-1000 keV) in the total time interval is 
(4.13 +/- 0.24)E-06 erg/cm^2. The 1-sec peak photon flux measured 
starting from T0+2.0 s in the 8-1000 keV band 
is 1.54 +/- 0.43 ph/s/cm^2.

The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090610C
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9509
SUBJECT: GRB 090610C: Fermi GBM detection
DATE:    09/06/12 16:29:53 GMT
FROM:    Adam Goldstein at Fermi-GBM/UAH  <adam.m.goldstein@msfc.nasa.gov>

A. Goldstein (UAH) reports on behalf of the Fermi GBM Team: 

"At 21:12:07.73 UT on 10 June 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090610C (trigger 266361129 / 090610883).

The on-ground calculated location, using the GBM trigger 
data, is RA = 70.4, DEC = +30.3 (J2000 degrees, 
equivalent to 04h 42m, 30d 18'), with an uncertainty 
of 8.2 degrees (radius, 1-sigma containment, 
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 104 degrees.

The GBM light curve consists of a single pulse
with a duration (T90) of about 18.1 s (8-1000 keV). 
The time-averaged spectrum from T0-4.1 s to T0+8.2 s is 
best fit by a simple power law function with index -1.62 +/- 0.08
(chi squared 341.6 for 362 d.o.f.).

The event fluence (8-1000 keV) in this time interval is 
(8.54 +/- 0.38)E-07 erg/cm^2. The 1-sec peak photon flux 
measured starting from T0-0.51 s in the 8-1000 keV band 
is 1.12 +/- 0.11 ph/s/cm^2.

The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090612A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9510
SUBJECT: GRB 090612: Fermi GBM detection
DATE:    09/06/15 15:15:49 GMT
FROM:    Narayana Bhat at U Alabama/Huntsville/GBM  <Narayana.Bhat@nasa.gov>

C. A. Meegan (USRA) and P. N. Bhat (UAH)
report on behalf of the Fermi GBM Team:

"At 14:50:50.49 UT on 12 June 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090612 (trigger 266511052 / 090612619 ).

The on-ground calculated location, using the GBM trigger
data, is RA = 81.1, DEC = 17.8 (J2000 degrees,
equivalent to 05h 24.3 m, 17 d 45'), with an uncertainty
of 2.2 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 56 degrees.

The GBM light curve shows of single strong pulse preceded by
weaker pre-trigger emission with a duration (T90) of about 58 s (8-1000
keV). 
The time-averaged spectrum from T0-1.024 s to T0+5.12 s is
adequately fit by a Band function with Epeak = 357 +/- 59 keV,
alpha = -0.6 +/- 0.1, and beta = -1.9 +/- 0.1

(chi squared 679.7 for 604 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(2.37 +/- 0.14)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0 s in the 8-1000 keV band
is 1.63 +/- 0.1 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090616A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9511
SUBJECT: GRB 090616: Fermi GBM detection
DATE:    09/06/17 08:59:09 GMT
FROM:    Elisabetta Bissaldi at MPE  <ebs@mpe.mpg.de>

Elisabetta Bissaldi (MPE) reports on behalf of the Fermi GBM Team:


"At 03:45:42.53 UT on 16 June 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090616 (trigger 266816744 / 090616157).
The on-ground calculated location, using the GBM trigger
data, is RA =  103.1, DEC = -3.7 (J2000 degrees,
equivalent to 06h 52m, -03d 42'), with an uncertainty
of 10.4 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
 
The angle from the Fermi LAT boresight is 68 degrees.

The GBM light curve shows a single pulse
with a duration (T90) of about 2.7 s (8-1000 keV).
The time-averaged spectrum from T0-0.128 s to T0+0.512 s
is adequately fit by a simple power law function with
index -1.27 +/- 0.07 (chi squared 290 for 360 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(2.23 +/- 0.09)E-07 erg/cm^2. The 256-msec peak photon flux measured
starting from T0-0.128 s in the 8-1000 keV band
is 2.08 +/- 0.11 ph/s/cm^2.


The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090618A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9512
SUBJECT: GRB 090618: Swift detection of a bright burst with optical afterglow
DATE:    09/06/18 08:48:39 GMT
FROM:    Jamie A. Kennea at PSU/Swift-XRT  <kennea@astro.psu.edu>

P. Schady (MSSL-UCL), W. H. Baumgartner (GSFC/UMBC),
A. P. Beardmore (U Leicester), S. Campana (INAF-OAB),
P.A. Curran (MSSL-UCL), C. Guidorzi (U Ferrara), J. A. Kennea (PSU),
J. Mao (INAF-OAB), R. Margutti (Univ Bicocca&OAB),
J. P. Osborne (U Leicester), K. L. Page (U Leicester),
P. Romano (INAF-IASFPA), M. H. Siegel (PSU), G. Stratta (ASDC) and
T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:

At 08:28:29 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090618 (trigger=355083).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 294.021, +78.353 which is 
   RA(J2000) = 19h 36m 05s
   Dec(J2000) = +78d 21' 13"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed multi peak
structure with a duration of about 130 sec.  The peak count rate
was ~40,000 counts/sec (15-350 keV), at 80 sec after the trigger. 

The XRT began observing the field at 08:30:30.8 UT, 120.9 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 293.9897, +78.3576 which is equivalent to:
   RA(J2000)  = 19h 35m 57.52s
   Dec(J2000) = +78d 21' 27.3"
with an uncertainty of 4.7 arcseconds (radius, 90% containment). This
location is 28 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy. 

UVOT took a finding chart exposure of 150 seconds with the White   
filter  starting 128 seconds after the BAT trigger. There is a   
candidate afterglow in  the rapidly available 2.7'x2.7' sub-image at 

  RA(J2000)  = 19:35:58.69 = 293.99456    
  DEC(J2000) = +78:21:24.3  = 78.35676      with a 90%-confidence
error radius of about 0.74 arc sec. This position   is 4.6  arc sec. 
from the center of the XRT error circle. The estimated   magnitude is
 14.36 with  a 1-sigma error of about 0.01. No correction has   been
made for the expected extinction corresponding to E(B-V) of 0.09. 

Burst Advocate for this burst is P. Schady (ps AT mssl.ucl.ac.uk). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB090618A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9513
SUBJECT: GRB090618: P60 Optical Afterglow
DATE:    09/06/18 08:49:37 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko@srl.caltech.edu>

S. B. Cenko (UC Berkeley) reports on behalf of a larger collaboration:

We have imaged the field of GRB090618 (Swift trigger 355083) with the
automated Palomar 60-inch telescope beginning at 08:30 UT on 18 June 2009
(approximately 2 minutes after the burst).  At the edge of the XRT error
circle we detect a bright point source with coordinates:

 RA: 19:35:58.68  Dec: +78:21:24.4 (J2000)

Using several SDSS stars in the field as reference, we estimate
an initial magnitude of r' ~ 13.8.  Given the brightness of the source,
we consider it highly likely to be the optical afterglow of GRB090618.

Further observations are ongoing.


GRB_name: GRB090618A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9514
SUBJECT: GRB 090618: KAIT optical afterglow
DATE:    09/06/18 08:52:20 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>

D. A. Perley reports on behalf of the KAIT GRB team:

The Katzman Automatic Imaging Telescope (KAIT) responded to GRB 090618 
and began taking data at 08:31:10 (UT).  A bright (~14th magnitude) 
optical afterglow is visible in the initial set of exposures at the 
following position:

RA   19:35:58.80
dec +78:21:25.5

Further follow-up is in progress.


GRB_name: GRB090618A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9515
SUBJECT: GRB 090618: ROTSE-III Detection of Optical Counterpart
DATE:    09/06/18 08:57:11 GMT
FROM:    Wiphu Rujopakarn at U AZ/Steward  <wiphu@as.arizona.edu>

W. Rujopakarn (Steward), T. Guver (U Arizona), S. B. Pandey (Michigan),
and F. Yuan (Michigan) report on behalf of the ROTSE collaboration:

ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB
090618 (Swift trigger 355083, Schady et al., GCN 9512). The first image
was at 08:28:53.7 UT, 23.9 s after the burst (6.7 s after the GCN notice
time). The unfiltered images are calibrated relative to USNO A2.0. We
detect a 14.1 magnitude source with coordinates:

19:35:58.65 +78:21:24.03    (J2000), with positional uncertainty of 1" or
better

start UT     mag     mlim(of image)
----------------------------------
08:28:29.8     14.1 16.2

This source is not visible in DSS (second epoch), 2MASS or the MPChecker
database. Continuing observations are in progress.


GRB_name: GRB090618A
Detection_method: KAIT
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9517
SUBJECT: GRB 090618: OA behavior from KAIT
DATE:    09/06/18 11:21:26 GMT
FROM:    Weidong Li at UC Berkeley KAIT/LOSS  <weidong@astron.berkeley.edu>

W. Li, D. A. Perley, and A. V. Filippenko, University of California at
Berkeley, on behalf of the KAIT GRB team:

We have analyzed the KAIT observations on GRB 090618 (GCN 9512) as
reported in GCN 9514. Our first 2s unfiltered observation started
at 08:29:44 UT, 75 s after the BAT trigger. The OA as reported in
GCN 9512, 9513, 9514, and 9515 is clearly detected. Subsequent 
observations show that the OA declined and reached a bottom at t=92 s,
then brightened and reached a peak at t=120 s. After the peak, the
OA declined as a smooth power-law, with an obvous change of decay
index at t ~ 600 s (from alpha = -1.08 +/- 0.05 to -0.70 +/- 0.02). 
Selected photometry, all unfiltered calibrated to the R band via USNO B1:

t_mid(seconds) exp(s)     mag   mag_err
---------------------------------------
          76    2.0      13.61  0.03  
          92    2.0      13.99  0.04  
         117    2.0      13.50  0.03  
         237   20.0      14.02  0.02 
         436   20.0      14.73  0.02  
         729   20.0      15.26  0.02 
 2601   20.0      16.22  0.02 
        7329  120.0      17.02  0.03  


GRB_name: GRB090618A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9518
SUBJECT: GRB 090618: Lick/KAST Spectroscopy
DATE:    09/06/18 12:37:12 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko@srl.caltech.edu>

S. B. Cenko, D. A. Perley (UC Berkeley), V. Junkkarinen, M. Burbidge (UC
San Diego), and K. Miller (UCO Lick Observatory) report on behalf of a
larger collaboration:

We have obtained a spectrum of the afterglow (GCNs 9512, 9513, 9514, 9515)
of GRB 090618 with the KAST spectrograph on the 3-m Shane telescope at
Lick Observatory.  Observations began at 08:48 UT on 18 June 2009,
approximately 20 minutes after the burst.  On the blue channel (using the
830/3460 grism, providing wavelength coverage from 3200 - 4400 A), we
detect a number of strong absorption features that we identify as Mg II,
Mg I, and Fe II at a common redshift of z = 0.54.  We believe this likely
to be the redshift of the GRB, as the lack of Lyman-alpha absorption
limits the GRB host to lie at z <~ 1.6.

Further analysis is in progress.


GRB_name: GRB090618A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9519
SUBJECT: Optical observations of GRB 090618
DATE:    09/06/18 12:37:13 GMT
FROM:    Alberto Carraminana at AzTEC  <alberto@inaoep.mx>

A. Carraminana (INAOE), C. Alvarez Ochoa (UNACh)
and G. Miramon (OAGH-INAOE) report:

We clearly detected the optical counterpart of GRB 090618 (GCN 9512)
with the 2.1m telescope of the Observatorio Astrofisico
Guillermo Haro at Cananea, Sonora, Mexico. Observations started
at 08:43 UT, 14 minutes after the BAT trigger and continued
until dawn. Observations were made under non photometric conditions.

We measured a lineal faddening of the burst compared to
a reference star of amplitude 0.5 magnitudes between t=870s
to 1600s. A non calibrated graph is available at

http://www.inaoep.mx/~alberto/gamma/grb090618_lc.jpg

Spectroscopic data were also obtained and are under analysis.


GRB_name: GRB090618A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9520
SUBJECT: GRB 090618 Faulkes Telescope North observations
DATE:    09/06/18 13:32:21 GMT
FROM:    David Bersier at Liverpool John Moores U  <dfb@astro.livjm.ac.uk>

A.Melandri (Liverpool JMU), C. Guidorzi (U. Ferrara), D.  Bersier,
Z. Cano, I.A. Steele, C.G. Mundell (Liverpool JMU), P. O'Brien,
N.  Tanvir (U. Leicester) on behalf of a larger collaboration report:


We have been monitoring the field of GRB090618 (Swift trigger 355083),
with the Faulkes Telescope North (Hawaii), starting ~80 minutes after
the trigger time (Schady et al. GCN 9512).

Observations were performed with BVRi filters. The optical afterglow
reported by Cenko (GCN 9513), Perley (GCN 9514) and Rujopakarn et al.
(GCN  9515) is clearly visible and detected in all filters.
We find a magnitude of R=17.01  0.03 (at 2.5 hrs after the burst)
and R=17.25  0.05 (at 3.1 hrs). We confirm the decay of alpha~0.7
reported by Li et al. (GCN 9517).

Observations are continuing.


GRB_name: GRB090618A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9521
SUBJECT: GRB 090618: Enhanced Swift-XRT position
DATE:    09/06/18 15:00:51 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 2422 s of XRT Photon Counting mode data and 5 UVOT
images for GRB 090618, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 293.99304, +78.35702 which is equivalent
to:

RA (J2000): 19h 35m 58.33s
Dec (J2000): +78d 21' 25.3"

with an uncertainty of 1.7 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, arXiv:0812.3662).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB090618A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9522
SUBJECT: GRB 090618: LOAO R-band Observation
DATE:    09/06/18 15:01:20 GMT
FROM:    Myungshin Im at Seoul Nat U  <mim@astro.snu.ac.kr>

  M. Im, W.K. Park (CEOU/Seoul National Univ) and Y. Urata (NCU)
  on behalf of EAFON team.

   We observed GRB090618 (Schady et al. GCN 9512) in R using
  the 1.0m telescope at Mt. Lemmon (Arizona, US) operated by
  the Korea Astronomy Space Science Institute.
   The observation started about 50min after the BAT trigger.

   The first image taken with the mid-point at June 18,
  09:52 UT (53m42s after the BAT trigger) shows a clear detection
  of the afterglow at R=15.9 +- 0.1 mag, reported earlier by a number of
  groups (GCN 9513, 9514, 9515, 9520).
   The photometry was calibrated against R1mag of USNO-B1 stars
  in the vicinity of GRB.
   More data were taken, and they are being analyzed.

   We thank the LOAO operator, Y. Baek for her assistance of this
  observation.


GRB_name: GRB090617A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9523
SUBJECT: GRB 090617: Fermi GBM detection
DATE:    09/06/18 15:20:25 GMT
FROM:    Elisabetta Bissaldi at MPE  <ebs@mpe.mpg.de>

Elisabetta Bissaldi (MPE) reports on behalf of the Fermi GBM Team:


"At 04:59:58.58 UT on 17 June 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090617 (trigger 266907600 / 090617208).
The on-ground calculated location, using the GBM trigger
data, is RA = 78.9, Dec = +15.7 (J2000 degrees,
equivalent to 05h 16m, 15d 42'), with an uncertainty
of 4.2 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).

The angle from the Fermi LAT boresight is 45 degrees.

The GBM light curve consists of a single bright pulse
with a duration (T90) of about 0.45 s (8-1000 keV).
The time-averaged spectrum from T0-0.032 s to T0+0.192 s is
best fit by a Band function with Epeak = 684 (-200/+250) keV,
alpha = -0.45 (-0.27/+0.17) and beta = -2.00 (-0.20/+0.24)
(Castor Stat 626 for 604 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(4.68 +/- 0.20)E-07 erg/cm^2. The 32-msec peak photon flux
measured starting from T0-0.032 s in the 8-1000 keV band
is 10.0 +/- 0.5 ph/s/cm^2.


The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB090618A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9524
SUBJECT: GRB 090618: AGILE observations
DATE:    09/06/18 15:21:44 GMT
FROM:    Marco Feroci at IASF/INAF  <feroci@iasf-roma.inaf.it>

F. Longo, E. Moretti, G. Barbiellini, E. Vallazza (INFN Trieste),
M.Trifoglio, A. Bulgarelli, F. Gianotti F. Fuschino, M. Marisaldi,
C.Labanti, M.Galli, G.DiCocco (INAF/IASF Bologna), S. Cutini, C.
Pittori (ASDC), M.Tavani, E.Striani, G. Pucella, F. D'Ammando, 
V.Vittorini, A. Argan, A. Trois, G. Piano, S. Sabatini
(INAF/IASF Rome), E. Del Monte, M. Feroci, Y. Evangelista, I. Donnarumma,
L. Pacciani, P. Soffitta, E. Costa, F.Lazzarotto, I. Lapshov, M. Rapisarda
(INAF/IASF Rome) A. Giuliani, A. Chen, S. Mereghetti, F. Perotti, P.
Caraveo (INAF/IASF Milano), A. Pellizzoni, M. Pilia (INAF/OA Cagliari), S. 
Vercellone (INAF/IASF Palermo), P. Picozza, A. Morselli (INFN Roma-2), M. 
Prest (Universita' dell'Insubria), P. Lipari, D. Zanello (INFN Roma-1), A. 
Rappoldi, P. Cattaneo (INFN Pavia) and P. Giommi, P. Santolamazza, F. 
Verrecchia (ASDC) and L. Salotti (ASI), on behalf of the AGILE Team, 
report:


The AGILE satellite detected GRB 090618 (P. Schady et al. GCN #9512)
at about 36 degrees off axis.
 
Super-AGILE, operating in the 18-60 keV energy range, triggered and 
localized the burst in the 1-D region of the field of view at a position
consistent with the Swift/BAT localization. The emission from this bright 
GRB with a complex lightcurve was detected at high significance despite 
the large off-axis direction.

AGILE-MCAL, operating in the 350 keV - 100 MeV energy range, triggered
this GRB at 08:28:24.772 UT (T0).  The MCAL overall burst duration is
about 100 sec. The burst is composed by three main pulses, the
brightest starting at T0+62sec and lasting about 14 seconds.
The total MCAL spectrum between T0 and T0+120 sec can be fit by a
simple powerlaw with photon index 3.16 (-0.30, +0.39) (90% c.l.),
with reduced chi^2 0.99 (9 d.o.f.), in the 0.5-10 MeV energy range.
The estimated fluence is (3.2 +/- 0.6) 10^{-5} erg cm^-2 in the same
energy range.

From a preliminary analysis of the AGILE-GRID data in the energy range
30 MeV-30 GeV no significant gamma-ray emission above 30 MeV is detected
in the GRB error box during both the first and second main pulse for
a total duration of about 130 sec. A preliminary upper limit is 0.1
ph cm^-2 over a 130 s duration.

GRB 090618 provides a clear evidence for a class of GRBs bright below 
a few MeV, showing the lack of significant gamma-ray emission above 30 
MeV.


GRB_name: GRB090531A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9525
SUBJECT: Swift XRT observations of GRB 090531A 
DATE:    09/06/18 16:21:56 GMT
FROM:    Boris Sbarufatti at INAF-IASF-Pa  <sbarufatti@ifc.inaf.it>

B. Sbarufatti, V. Mangano (INAF-IASFPA) on behalf of the Swift-XRT team.

The XRT onboard Swift observed the field of GRB 090531A on 2009 June  
10 and 2009 June 17, after it came outside the Moon observing  
contstraint, for a total exposure of 35.5 ks in Photon Counting mode.

Three significant sources are detected inside the initial BAT error  
circle (Stamatikos, et al., GCN circ. 9454). Two of them, detected at  
a level of 1.2E-3 counts/s and 9.0E-4 counts/s, are compatible with a  
stable count-rate and are found outside the BAT refined error circle  
(Sakamoto, et al., GCN circ. 9460). The third source, detected at a  
level of 6.5E-4 counts/s is too faint to estimate if it is fading or  
not, and it is found just inside the BAT refined error circle, at a  
distance of 64.8 arcsec from the BAT refined position. Its coordinates  
are RA,Dec = 178.65539, +7.81671 which is:

RA(J2000)  =  11h 54m 37.29s
Dec(J2000) = +07d 49' 00.2"

with an uncertainty of 4.8 arcsec (radius, 90% confidence).

This circular is an official product of the Swift-XRT team.


GRB_name: GRB090618A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9526
SUBJECT: GRB 090618: SDSS host detection
DATE:    09/06/18 16:52:52 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@astro.ku.dk>

Daniele Malesani (DARK/NBI) reports:

I inspected the SDSS images of the field of GRB 090618 (Schady et al., 
GCN 9512). A faint object is visible in the r and i frames at the 
position of the optical afterglow (e.g. Schady et al., GCN 9512; Cenko, 
GCN 9513), likely the host galaxy of the GRB. Nothing convincing is 
visible in the u, g, and z images. Compared to nearby SDSS stars, the 
magnitudes are r = 22.7 +- 0.3 and i = 22.2 +- 0.4. The bright host 
magnitude is consistent with the low redshift reported by Cenko et al. 
(GCN 9518)

A supernova as bright as SN 1998bw (Galama et al. 1998, Nature, 395, 
670) would peak at r(AB) ~ 23.6 at z=0.54.


GRB_name: GRB090618A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9527
SUBJECT: GRB090618: Swift/UVOT bright afterglow detection
DATE:    09/06/18 19:00:10 GMT
FROM:    Patricia Schady at MSSL/Swift  <ps@mssl.ucl.ac.uk>

P. Schady (MSSL-UCL) reports on behalf of the Swift UVOT team:

The Swift/UVOT began settled observations of the field of GRB 090618 129s 
after the BAT trigger (Schady et al., GCN Circ. 9512) and a 
decaying source is detected in all UVOT filters at the position reported 
in Schady et al. (GCN Circ. 9512), consistent with refined XRT error 
circle (Evans et al., GCN Circ. 9521) as well as the optical afterglow 
position reported in a number of other GCNs (GCN Circ. 9512, 9514, 9515). 
The detection of the afterglow of GRB 090618 in all filters puts an upper 
limit on the redshift of z < 1.7, consistent with the redshift constraints 
reported by Cenko et al. (GCN Circ. 9518).

The magnitudes for the first UVOT observation of GRB 090618 in each filter 
are as follows:

Filter  T_start(s)  T_stop(s)  Exp(s)      Mag
white      129        279       147    14.27+/-0.01
v          671        691       19     15.60+/-0.09
b          596        616       19     15.92+/-0.06
u          340        590       246    14.62+/-0.01
uvw1       720        740       19     15.09+/-0.08
uvm2       695        715       19     15.23+/-0.12
uvw2       647        667       19     15.27+/-0.10

The values quoted above are not corrected for the Galactic extinction due 
to the reddening of E(B-V) = 0.09 in the direction of the burst 
(Schlegel et al. 1998). The photometry is on the UVOT photometric system 
described in Poole et al. (2008, MNRAS, 383, 627).


