# GCN_circulars

GRB_name: GRB090812A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9814
SUBJECT: VLA radio non-detection of GRB 090812
DATE:    09/08/16 02:03:58 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
GRB 090812 (GCN 9768) at a frequency of 8.46 GHz at two epochs, on
2009 Aug. 13.37 UT and Aug. 15.41 UT. The GRB radio afterglow is
undetected in both the observations. The peak fluxes at the P60
optical afterglow position (GCN 9769) in the two observations are
104+/-43 uJy and 63+/-62 uJy, respectively.

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


GRB_name: GRB090817A
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9815
SUBJECT: GRB 090817: a long GRB localized by INTEGRAL
DATE:    09/08/17 02:53:44 GMT
FROM:    Volker Beckmann at ISDC  <Volker.Beckmann@obs.unige.ch>

V.Beckmann (ISDC, Versoix), D.Gotz (CEA-Saclay), S.Mereghetti,
A.Paizis (IASF-Milano), A. Neronov, M. Beck (ISDC, Versoix), and J.
Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report:

A long GRB with duration of about 250 s has been detected by IBAS in
IBIS/ISGRI data at 00:51:33 UT on August 17th.

The refined coordinates (J2000) are:

   RA:   63.9659 [degrees]
   DEC: +44.1234 [degrees]

with an uncertainty of 2.6 arcmin (90% c.l.).

The light curve shows two prominent peaks at T0 and at T0+196s. A plot  
of the light curve will be posted at

http://ibas.iasf-milano.inaf.it/IBAS_Results.html

This message can be cited.


GRB_name: GRB090812A
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9816
SUBJECT: GRB 090812: Suzaku WAM observation of the prompt emission
DATE:    09/08/17 09:36:54 GMT
FROM:    Kazuhiro Noda at Miyazaki U  <kaz1206@astro.miyazaki-u.ac.jp>

K. Noda, E. Sonoda, N. Ohmori, K. Kono, H. Hayashi,
A. Daikyuji, Y. Nishioka, M. Yamauchi (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 090812 (Swift/BAT trigger #359711; 
Stamatikos et al., GCN 9768; Baumgartner et al., GCN 9775) 
triggered the Suzaku Wide-band  All-sky Monitor (WAM) which covers an 
energy range of 50 keV - 5 MeV at 2009-08-12 06:02:33.68 UT (=T0). 

The observed light curve shows a double-peaked structure, starting at 
T0-30 s and ending at T0+40 s, with a total duration (T90) of about 36 s. 
The fluence in 100 - 1000 keV was 1.50(-0.46, +0.40) x10-6 erg/cm2.
The 1-s peak flux measured from T0+2 s was 2.77(-0.35, +0.23) photons/cm2/s 
in the same energy range.

Preliminary result shows that the time-averaged spectrum from
T0-30 s to T0+40s is well fitted by a power-law with exponential cutoff model:
  dN/dE ~  E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
  alpha:     1.31(-1.09, +0.81), and
  Epeak:     340(-138, +254) keV (chi2/d.o.f. = 36.6/37).

All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.

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: GRB090813A
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9817
SUBJECT: GRB 090813: Suzaku WAM observation of the prompt emission
DATE:    09/08/17 09:43:52 GMT
FROM:    Takeshi Uehara at Hiroshima U  <uehara@hirax7.hepl.hiroshima-u.ac.jp>

GRB 090813: Suzaku WAM observation of the prompt emission

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

The long, GRB 090813 
(Swift/BAT trigger #359884 ; Cummings et al., GCN 9781; 
Fermi GBM trigger #271829444 ) 
triggered the Suzaku Wide-band  All-sky Monitor (WAM) 
which covers an energy range of 50 keV - 5 MeV at 04:10:43.2 UT (=T0). 
The observed light curve shows a double-peaked structure 
lasting from T0-0.8s to T0+1.2s followed by a long weak tail seen up
to T0+6.8s with a duration (T90) of about 7.6 seconds. 
The fluence in 100 - 1000 keV was 1.70 (-0.51, +0.61) 10^-6 erg/cm^2. 
The 1-s peak flux measured from T0-0.2s was 2.77 (-0.40, +0.35) 
photons/cm^2/s in the same  energy range.

Preliminary result shows that the time-averaged spectrum from T0-0.8s to 
T0+6.8s is well fitted by a single power-law with a photon index 
of 1.80 (-0.30, +0.40) (chi^2/d.o.f = 7.6/8).
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: GRB090814A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9818
SUBJECT: GRB 090814A: optical observations
DATE:    09/08/17 11:07:26 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

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

We observed the field of GRB 090814A (Ukwatta et al. GCN 9793; Updike et 
al., GCN 9794) with   Shajn telescope of  CrAO on Aug. 14 between  (UT) 
19:02:44 - 19:56:58 under modarate seeing of about 1.9 arcsec. We  detect 
afterglow   in a stacked image. The coordinates of the afterglow are (J2000) 
15 58 26.36 +25 37 52.32 in a full agreement with reported earlier (A. 
Updike et al., GCN 9794).  The photometry against nearby USNO-B1.0 star 15 
58 23.11  +25 39 07.2  16.64 R is following:

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

   R     51x60     22.10 +/- 0.08

We confirm the shallow decay of the afterglow (D. Xu et al., GCN 9809) with 
power law index ~0.3. 


GRB_name: GRB090817A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9819
SUBJECT: GRB 090817: Swift-XRT observations
DATE:    09/08/17 13:59:42 GMT
FROM:    Kim Page at U.of Leicester  <kpa@star.le.ac.uk>

P.A. Evans (U. Leicester), C. Guidorzi (U Ferrara) and W.H. Baumgartner
(GSFC/UMBC) report on behalf of the Swift-XRT team:

The Swift-XRT observed the field of GRB 090817 (Beckmann et al. GCN
Circ. 9815) from T0+11 ks to T0+17.5 ks gathering 1.8 ks of Photon
Counting (PC) mode data.

Inside the INTEGRAL error circle we find a single, uncatalogued X-ray
source at RA, Dec = 63.96600, 44.12900 which is equivalent to:

RA (J2000):  04 15 51.85
Dec (J2000): +44 07 44.5

with an uncertainty of 2.0 arcsec (radius, 90% confidence). The optical
source USNO-B1.0 1341-0096763 lies only 1.3 arcsec from the XRT
position. This object is point-like in USNO-B1, with magnitudes I=18.5,
R=20.0, B=20.8.

The light curve of the X-ray source shows a rapid rise from 0.04 ct/sec
at T0+11 ks to 0.1 ct s^-1 at T0+12 ks; by T0+18 ks the count rate has
returned to 0.04 ct s^-1.  A spectrum formed from the PC mode data can
be modelled with an absorbed power law with a photon index of 2.5 (+0.7,
-0.6) with an absorption column of 9.5 (+4.9, -4.0) x 10^21 cm^-2, in
excess of the Galactic value of 4.0 x 10^21 cm^-2 (Kalberla et al.
2005).

Given the light curve of this source, it is not clear whether or not
this is a GRB afterglow. A further observation has therefore been
planned, and will take place today.

No other sources are detected in the INTEGRAL error circle, with a
3-sigma upper limit of 5 x 10^-3 ct s^-1. Using the typical
counts-to-observed-flux conversion factor from Evans et al (2009, MNRAS,
397, 1177) this gives a flux limit of 1.7 x 10^-13 erg cm^-2 s^1.

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



-- 
-------------------------

Phil Evans,
Swift Development Scientist
X-ray and Observational Astronomy Group,
University of Leicester

Tel: (0116) 252 5059
pae9@star.le.ac.uk
http://www.star.le.ac.uk/~pae9


GRB_name: GRB090813A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9820
SUBJECT: GRB 090813: I-band observations from 1.5m OSN telescope
DATE:    09/08/17 15:09:25 GMT
FROM:    Javier Gorosabel at IAA-CSIC  <jgu@iaa.es>

J. Gorosabel (IAA-CSIC), A. de Ugarte Postigo (INAF-OAB), A. Sota (IAA- 
CSIC),  S. Guziy (IAA-CSIC),  M. Jelinek (IAA-CSIC), P. Kubanek (IAA- 
CSIC & IPL Univ. Valencia), A.J. Castro-Tirado (IAA-CSIC), report;

We performed I-band observations of the GRB 090813 optical afterglow  
(Gorosabel et al. GCN 9782; Cenko et al. GCN 9783; Smith et al. GCN  
9784) with the 1.5m telescope of Observatorio de Sierra Nevada. The  
observations were carried on Aug 13.8979 - 13.9667 UT with a total  
exposure time of 4950 seconds. No object brigther than I = 21.9 was  
detected at the afterglow position.


GRB_name: GRB090812A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9821
SUBJECT: GRB 090812: Konus-Wind and Swift/BAT joint spectral analysis
DATE:    09/08/17 15:28:46 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val@mail.ioffe.ru>

V. Pal'shin, S. Golenetskii, R.Aptekar, E. Mazets, D. Frederiks, and
T. Cline on behalf of the Konus-Wind team,

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),
D. Palmer (LANL), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), and T. Ukwatta (GWU)

report:

The most intense pulse of the long GRB 090812 (Swift/BAT trigger
#359711: Stamatikos et al., GCN Circ. 9768, Baumgartner et al. GCN Circ. 
9775) triggered Konus-Wind at T0(KW)=21758.942 s UT (06:02:38.942).
Since the Konus-Wind trigger record misses the early weaker part of this 
GRB, we have only Konus-Wind 3-channel spectral data for the whole burst 
which cover the energy range from 23 keV to 1.4 MeV.
We performed the Konus-Wind and Swift/BAT joint spectral analysis of
this GRB to derive the broad-band spectral and energetic parameters of
this burst.

The time interval of the spectral data is chosen from
T0(BAT)-6.7 to T0(BAT)+58.1 sec where T0(BAT) is the trigger time
of BAT at 06:02:08.897 UTC.  The energy ranges which we used in the
joint spectral analysis are 23-1400 keV and 15-150 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 15%.  No systematic residual from the
best fit model is seen in the spectral data of each instrument.  The
best fit spectral parameters are: alpha = -1.03(-0.06, +0.07) and Epeak
= 586(-152, +243) keV (chi2/dof = 59.3/57).  The best fit spectral
parameters for the GRB (Band) model fixing beta = -2.5 are:
alpha = -1.03 +/- 0.07, and Epeak = 572(-159, +251) keV (chi2/dof = 
59.6/57). The energy fluence in the 15-1400 keV band calculated by a 
power-law with exponential cutoff model for this 64.8 sec interval is 
(2.61 +/- 0.34)x10^-5 erg/cm2 (assuming the constant factor of the 
Konus-Wind is fixed to 1).

Assuming z = 2.452 (de Ugarte Postigo et al. GCN Circ. 9771) 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 = 4.4 (-0.6,
+0.7)x10^53 erg in 1 keV to 10 MeV at the GRB rest frame extrapolating
the best Band function fit fixing beta = -2.5, and the rest frame peak 
energy is Epeak_rest = 2.0(-0.5, +0.9) MeV.

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/GRB090812_T21758/


GRB_name: GRB090817A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9822
SUBJECT: GRB 090817: Swift/UVOT Upper Limits
DATE:    09/08/17 15:58:28 GMT
FROM:    Alice Breeveld at MSSL-UCL  <aab@mssl.ucl.ac.uk>

  A. Breeveld (MSSL/UCL) and W. Baumgartner (GSFC) report on behalf of  
the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 090817   
11008 s after the INTEGRAL trigger (Beckmann et al., GCN Circ. 9815).  
No new sources are found in the UVOT data at the position of the XRT  
source (P.A. Evans et al., GCN Circ. 9819). Preliminary 3-sigma upper  
limits using the UVOT photometric system (Poole et al. 2008, MNRAS,  
383, 627) and a 3 arcsec radius aperture, for the initial summed  
exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white         11516        17719          413         >21.3
v                11975        12398          416         >19.6
b                11058        17509          787         >21.2
u                11008        17157           78         >19.5

The values quoted above are not corrected for the Galactic extinction  
due to the reddening of E(B-V) = 0.66 in the direction of the burst  
(Schlegel et al. 1998).


GRB_name: GRB090817A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9823
SUBJECT: GRB 090817: Fermi GBM observation
DATE:    09/08/17 18:23:30 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 00:51:26.21 UT on 17 August 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090817 (trigger 272163088 / 090817036).
which was also detected by INTEGRAL (Beckmann et al. 2009, GCN 9815)
The GBM on-ground location is consistent with the INTEGRAL position.
 
The angle from the Fermi LAT boresight is 82 degrees.

The GBM light curve consists of an initial bright peak at the trigger time
followed by a weak broad bump about 200 s after the trigger. This burst has
a duration (T90) of about 220 s (8-1000 keV).

Spectral analysis was performed only for the bright initial peak. The
time-averaged spectrum from T0 to T0+41 s is adequately fit by a Band
function with Epeak = 115 +/- 50 keV, alpha = -1.1 +/- 0.3, and
beta = -2.2 +/- 0.6

The event fluence (8-1000 keV) over the T90 interval is
(7.3 +/- 0.1)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.15 s in the 8-1000 keV band
is 3.8 +/- 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: GRB090815C
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9824
SUBJECT: GRB 090815C: Swift refined analysis
DATE:    09/08/17 20:41:44 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), P.A. Evans (U. Leicester)
on behalf of the Swift Team:

At 23:21:39 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090815C (trigger=360068).  No GCN Notices were issued
because the trigger was below the normal acceptance level.  Also,
the spacecraft did not execute an automated slew to the location
because of an Earth observing constraint.  Later, ground-processing
using the full data set T-60 to T+303 sec determined the location to be
RA, Dec = 64.490, -65.943 deg, which is
   RA(J2000)  =  04h 17m 57.6s
   Dec(J2000) = -65d 56' 33.5"
with an uncertainty of 2.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 76%.

The BAT mask-weighted light curve shows a single weak peak.  T90 (15-350 keV)
is 0.6 +- 0.3 sec (estimated error including systematics).

The time-averaged spectrum from T-0.0 to T+0.7 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
0.90 +- 0.47.  The fluence in the 15-150 keV band is 4.4 +- 1.2 x 10^-8 erg/cm2.
The 1-sec peak photon flux measured from T-0.18 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/360068/BA/

Based on the ground-processing of the full BAT data, a ToO was executed
6.1 hours after the trigger.  Swift-XRT obtained 4.3 ks of Photon Counting
(PC) mode data, from T0+22 ks to T0+56 ks.  No source is found in the BAT
error circle, with a 3-sigma upper limit of 1.9 x 10^-3 ct/sec;
for a typical GRB, this corresponds to an upper limit on the observed
0.3-10 keV flux of 7 x 10^-14 erg cm^-2 s^-1.


GRB_name: GRB090817A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9825
SUBJECT: GRB 090817: Confirmation of the X-ray afterglow
DATE:    09/08/18 08:52:01 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

P.A. Evans (U. Leicester), C. Guidorzi (U Ferrara) and W.H. Baumgartner
(GSFC/UMBC) report on behalf of the Swift-XRT team:

Swift conducted a second observation of GRB 090817 (Beckmann et al. GCN
Circ. 9815), collecting 3.9 ks of Photon Counting (PC) mode XRT data in
the interval T0+50 ks to T0+58 ks. The source reported by Evans et al.
(GCN Circ. 9819) has faded to a level of ~0.015 ct s^-1. A power-law fit
to the light curve yields a temporal decay index of alpha=0.9+/-0.2

Inspecting the USNO-B1 catalogue within 3.5' of the GRB we find 216
objects with R2<20.0. The probability of finding a USNO-B1 source within
a 2" radius circle in this field is thus 2%. The strength of the
potential association between the XRT and USNO-B1 sources noted in GCN
Circ. 9819 is therefore fairly weak.

We therefore suggest that the XRT source is the afterglow of GRB 090817.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020108.

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


GRB_name: GRB090817A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9826
SUBJECT: GRB 090817: optical upper limit
DATE:    09/08/18 12:02:36 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

V. Rumyantsev (CrAO), A. Pozanenko (IKI), M. Andreev (Terskol Branch of 
Institute of Astronomy)  report on behalf of  larger GRB  follow-up 
collaboration:

We observed a field of the INTEGRAL GRB 090817 (Beckmann et al., GCN 9815) 
with Shajn telescope of  CrAO starting on Aug. 17 (UT) 01:07, i.e. ~17 
minutes after burst onset. A series of 37 images of 60 s exposure was 
obtained in R filter. Within XRT error circle of  the afterglow (Evans et 
al., GCN 9819, GCN 9825) we do not detect any new object. The quoted 
USNO-B1.0 star USNO-B1.0 1341-0096763 (Evans et al., GCN 9819) does not 
change its brightness within ~0.08 m during our observations. An upper limit 
of a single frame of 60 s exposure is R~21.5 m. Data reduction is 
continuing.


GRB_name: GRB090817A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9827
SUBJECT: GRB 090817: Liverpool Telescope Observations
DATE:    09/08/18 18:56:21 GMT
FROM:    Zach Cano at ARI/John Moores Liverpool  <zec@astro.livjm.ac.uk>

GRB 090817: Liverpool Telescope Observations

Z. Cano,  I.A. Steele, C.G. Mundell,  A. Melandri, S. Kobayashi, C.J.
Mottram, R.J. Smith, D. Bersier (Liverpool JMU), A. Gomboc (U. Ljubljana),
report on behalf of a large collaboration:

On August 17 2009, 1.459 hours after the burst was detected, the 2-m
Liverpool Telescope automatically began observing the INTEGRAL GRB 090817
(Beckmann et al.,GCN Circ. 9815) using g',r' and i' filters.

We do not detect any uncatalogued source inside the Swift-XRT error circle
(Evans et al. GCN Circ 9819).  Upper limits in stacked R and I images for
isolated objects are 20.6 and 20.8 respectively.

Magnitudes have been calibrated from the nearby USNO star (1341-0096766):
04:15:52.314, +44:07:50.9 using R2=17.56 and I=17.04.

We note that the upper limits presented are the limits for detecting an
isolated object in our images.  As the USNO star (1341-0096763) lies only
1.3" from the XRT position the actual upper limits will be accordingly
brighter.


GRB_name: GRB090817A
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9828
SUBJECT: GRB 090817: aphotometry of USNO-B1.0 341-0096763 
DATE:    09/08/19 21:51:06 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

V. Rumyantsev (CrAO), A. Pozanenko (IKI), M. Andreev (Terskol Branch of
Institute of Astronomy)  report on behalf of  larger GRB  follow-up
collaboration:

We report a photometry of the USNO-B1.0 object 341-0096763 in the XRT error
circle of  the X-ray afterglow (Evans et al., GCN 9819, GCN 9825) of the
INTEGRAL GRB 090817 (Beckmann et al., GCN 9815).  The observations took
place  with Shajn telescope of  CrAO on Aug.17 (Rumyantsev et al., GCN
9826). The photometry is based on the reference star USNO B1.0 1341-0096766
(04 15 48.35  +44 08 07.7) assuming R = 17.54, only statistical errors are
quoted.  Upper limits are presented for isolated object. To make any
conclusion about variability of the star or the presence in the tail of the
star other possible source we are planning second epoch observation.

Date        Time start (UT)   Upper_Limit  R_mag

2009-08-17  01 09 36.45  21.5  19.33 +/-0.05
2009-08-17  01 10 40.62  21.5  19.38 +/-0.05
2009-08-17  01 13 23.49  21.7  19.43 +/-0.04
2009-08-17  01 14 27.16  21.7  19.32 +/-0.04
2009-08-17  01 15 30.91  21.8  19.35 +/-0.04
2009-08-17  01 16 34.72  21.9  19.46 +/-0.04
2009-08-17  01 17 38.27  21.9  19.40 +/-0.04
2009-08-17  01 18 41.93  21.9  19.44 +/-0.04
2009-08-17  01 19 45.99  21.7  19.39 +/-0.04
2009-08-17  01 20 49.53  21.7  19.37 +/-0.04
2009-08-17  01 21 53.11  21.8  19.45 +/-0.04
2009-08-17  01 22 58.16  21.7  19.40 +/-0.04
2009-08-17  01 24 01.75  21.8  19.28 +/-0.04
2009-08-17  01 25 05.64  21.8  19.45 +/-0.04
2009-08-17  01 26 09.20  21.8  19.46 +/-0.04
2009-08-17  01 27 12.86  21.8  19.39 +/-0.04
2009-08-17  01 28 16.41  21.8  19.38 +/-0.04
2009-08-17  01 29 22.52  21.6  19.38 +/-0.05
2009-08-17  01 30 26.12  21.6  19.39 +/-0.05
2009-08-17  01 31 29.63  21.6  19.38 +/-0.05
2009-08-17  01 32 33.37  21.7  19.33 +/-0.04
2009-08-17  01 33 38.37  21.6  19.39 +/-0.05
2009-08-17  01 34 42.08  21.6  19.38 +/-0.05
2009-08-17  01 35 45.77  21.6  19.42 +/-0.05
2009-08-17  01 36 49.51  21.5  19.46 +/-0.06
2009-08-17  01 37 53.18  21.4  19.34 +/-0.05
2009-08-17  01 38 56.70  21.3  19.55 +/-0.08
2009-08-17  01 40 00.31  21.3  19.44 +/-0.07
2009-08-17  01 41 06.39  21.2  19.30 +/-0.07
2009-08-17  01 42 12.89  21.2  19.47 +/-0.08
2009-08-17  01 43 16.53  21.1  19.41 +/-0.08
2009-08-17  01 44 20.34  21.1  19.43 +/-0.08
2009-08-17  01 45 24.13  20.9  19.41 +/-0.10
2009-08-17  01 46 28.68  20.9  19.42 +/-0.10
2009-08-17  01 47 32.26  20.7  19.29 +/-0.11
2009-08-17  01 48 35.81  20.7  19.52 +/-0.13


GRB_name: GRB090820A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9829
SUBJECT: GRB 090820: Fermi GBM Detection of a bright burst.
DATE:    09/08/20 06:58:15 GMT
FROM:    Valerie Connaughton at MSFC  <valerie@nasa.gov>

Valerie Connaughton (UAH) reports on behalf of the Fermi GBM Team:

"At 00:38:16.19 UT on 20 August 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090820027 (trigger 272421498 / 090820027).

The on-ground calculated location, using the GBM trigger
data, is RA = 87.7, DEC = 27.0 (J2000 degrees,
equivalent to 05h 51 m, 27 d 00 '), with an uncertainty
of 1.0 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 108 degrees.

Although this burst was bright enough to result in a Fermi spacecraft
repointing maneuver and ensuing pointed observations of the burst
position, Earth avoidance constraints prevented such a maneuver
until 3100 sec after the burst trigger.

The light curve shows GBM triggered on a weak precursor,
followed by a bright pulse beginning 30 s later and lasting a
further 30 s.  The time-averaged spectrum from T0+28 s to T0+60 s
is best fit by a Band function with Epeak = 215 +/- 3 keV,
alpha = -0.69  +/- 0.01, and beta = -2.61 - 0.05.

The event fluence (8-1000 keV) in this time interval is
(6.6 +/- 0.1)E-5 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+34 s in the 8-1000 keV band
is about 58 ph/s/cm^2.

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


GRB_name: GRB090820A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9830
SUBJECT: GRB 090820: MASTER-Net  optical polarization observations 
DATE:    09/08/20 16:35:57 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.Zalognih, T.Kopytova
Ural State University, Kourovka


There are 6 MASTER Very Wide Field cameras located at Kislovodsk and Irkutsk 
with common FOW = 2000 + 1680 square degrees (http://observ.pereplet.ru/).

Four   MASTER Very Wide Field Cameras located at Kislovodsk
(4 Carl Zeiss Planar T* 85/1.4 ZF, 4x420 square degrees, 11 Mpx, 22" per 
pix  with 4 polarizers) responded to 
the bright  GRB 090820 (Fermi TRIGGER_NUM:272421498, V. Connaughton, GCN 
9829), producing images beginning 9 s after the GRB Time (first alert notice).

We took 1300 images with 5 sec exposition in different polarizations.
Individual images have limiting magnitudes~11.

Our unfiltered images are calibrated relative to Tycho stars (V) and very close 
to V band.
Other observations are required for independ error box elaboration.

The reduction is continued.

The message may be cited.

mailto: lipunov@sai.msu.ru


GRB_name: GRB090817A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9831
SUBJECT: GRB 090817: Swift/UVOT Observations of a Host Galaxy Candidate
DATE:    09/08/20 19:17:42 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <Stephen.T.Holland@nasa.gov>

S. T. Holland (CRESST/GSFC/USRA), A. Breeveld (MSSL/UCL), and
W. Baumgartner (GSFC/UMBC) report on behalf of the Swift UVOT team:

      The Swift/UVOT observed the field of GRB 090817 (Beckman et al.,
2009, GCN Circ. 9815) between 11 ks and 284 ks after the INTEGRAL
trigger.  The USNO-B1.0 source 1341-0096763 (Evans et al. 2009, GCN
Circ. 9819, Rumyantsev et al. 2009, GCN Circ. 9828) is detected inside
the XRT error circle (Evans et al., 2009, GCN Circ. 9819). We find no
evidence for variability in this source during our observations.  
Preliminary
magnitudes and 3-sigma upper limits from all of the coadded data are

Filter    Exposure      Mag  Err Sigma
--------------------------------------
v              416    19.86 0.46   2.4
b              787    20.99 0.33   3.4
u             4003    21.49 0.30   3.7
uvw1          4326   >22.0   ...   ...
white          413    21.19 0.37   3.2

The quoted magnitudes and upper limits have not been corrected for the
expected Galactic extinction along the line of sight corresponding to
a reddening of E_{B-V} = 0.66 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).

       The UVOT coordinates of this source are

  RA (J2000)  04:15:51.85  =   63.96604 (deg)
Dec (J2000) +44:07:44.5   =  +44.12902 (deg)

with an estimated uncertainty of 1.0 arcsec (radius, 90% confidence,
statistical + systematic). The dereddened colours of the source are
not consistent with a stellar spectrum. However, the colours are
consistent with an Sm or Im galaxy (de Vaucouleurs, 1961, ApJS, 5,
233). This suggests that the source may be the host galaxy of GRB
090817.  If this galaxy has an absolute magnitude similar to that of
the LMC then it is located at a redshift of approximately z = 0.05.
An intrinsically fainter galaxy would be closer. Follow-up
spectroscopy is encouraged to verify this.


GRB_name: GRB090820B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9832
SUBJECT: GRB 090820B: Fermi GBM detection
DATE:    09/08/21 07:48:55 GMT
FROM:    Arne Rau at MPE  <arau@mpe.mpg.de>

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

"At 12:13:16.70 UT on 20 August 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090820B (trigger 272463198 / 090820509).

The on-ground calculated location, using the GBM trigger
data, is RA = 318.3, DEC = -18.6 (J2000 degrees,
equivalent to 21 h 13 m, -18 d 36 '), with an uncertainty
of 9.6 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 32 degrees.

The GBM light curve consists of two narrow peaks
with a duration (T90) of about 11.2 s (8-1000 keV).
The time-averaged spectrum from T0-0.128 s to T0+12.160 s is
best fit by a power law function with an exponential
high energy cutoff.  The power law index is -1.44 +/- 0.18 and
the cutoff energy, parameterized as Epeak, is 38.8 +/- 4.4 keV
(chi squared 336 for 356 d.o.f.)

The event fluence (8-1000 keV) in this time interval is
(1.16 +/- 0.07)E-06 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0-0.128 s in the 8-1000 keV band
is 6.1 +/- 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: GRB090820A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9833
SUBJECT: GRB 090820: detection of a strong burst by RT-2 on board CORONAS PHOTON
DATE:    09/08/24 06:34:33 GMT
FROM:    Sandip K. Chakrabarti at S.N. Bose Nat. Centre for Basic Sci.  <chakraba@bose.res.in>

GRB 090820: RT-2 detection of a strong burst


S. K. Chakrabarti, A. Nandi, D. Debnath, T. C. Kotoch (ICSP, Kolkata, 
India), A. R. Rao, J. P. Malkar, M. K. Hingar, V. K. Agrawal (TIFR, Mumbai, 
India),  T. R. Chidambaram, P. Vinod, S. Sreekumar (VSSC, 
Thiruvananthapuram, India), Y. D. Kotov, A. S. Buslov, V. N. Yurov, V. G. 
Tyshkevich, A. I. Arkhangelskij, R. A.Zyatkov (MephI, Moscow, Russia) report:

The RT-2 Experiment onboard the CORONAS-PHOTON satellite has detected GRB 
090820 (FERMI, Trigger No.- 272421498, V. Connaughton, GCN 9829) which 
is     triggered at T0 = 00h 38m 16s (UT) (Onboard processor switch/toggle 
to Flare mode from Quiet mode). The satellite was in the GOOD/LIGHT mode  
with Earth latitude = -64.09 and longitude = 169.11. with GOOD time 
observation of 600 sec starting at 00h 29m 16sec (UT) and ending at 00h 39m 
16sec (UT). After 30 sec, the satellite completely entered into BAD mode of 
high charge particle region.

The GRB light curve shows a simple profile of a strong emission peak at 
T0+34 sec with a weak precursor (T0). The time duration of the brightest 
emission is around 19 sec with ~1100 cts/sec.
 
Both RT-2/S and RT-2/G detectors have registered this burst profile in the 
energy band of 15 - 1000 keV with strongest emission in the energy range of 
above 100 keV to 330 keV. It is also noted that the burst width decreases 
with the increase in the energy band, a quite natural phenomena of GRB burst 
profile. 

This analysis is preliminary. Analysis of time resolved spectral data is 
going on, however
the light curve is available at the web-site: 
http://csp.res.in/rt2_files/grb090820-lc.html


GRB_name: GRB090817A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9834
SUBJECT: GRB 090817: Swift/UVOT Observations of a Possible Late-Time Brightening
DATE:    09/08/24 18:58:29 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <Stephen.T.Holland@nasa.gov>

S. T. Holland (CRESST/GSFC/USRA), A. Breeveld (MSSL/UCL), and
W. Baumgartner (GSFC/UMBC) report on behalf of the Swift UVOT team:

      Swift/UVOT observed the USNO-B1.0 source 1341-0096763 (Evans et
al. 2009, GCN Circ. 9819; Rumyantsev et al. 2009, GCN Circ. 9828;
Holland et al. 2009, GCN Circ. 9831), which is located inside the XRT
error circle (Evans et al., 2009, GCN Circ. 9819), at approximately 6
and 7 days after the INTEGRAL trigger (Beckman et al., 2009, GCN
Circ. 9815).  A preliminary examination of the UVOT data yields weak
evidence that the source may have brightened by approximately 0.5 mag
in the UVOT v band between approximately 6.5 and 7.1 days.  Our
observations are consistent with a supernova rising to maximum light.
However, we stress that further observations are needed to confirm
this.  Follow-up photometric and spectroscopic observations of this
source are strongly encouraged.


GRB_name: GRB090823A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9835
SUBJECT: GRB 090823 Long burst with IPN triangulation and BAT position
DATE:    09/08/25 01:36:20 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <jayc@milkyway.gsfc.nasa.gov>

J. R. Cummings (NASA/GSFC/CRESST) on behalf of the
Swift-BAT team,

S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin,
D. Frederiks, and T. Cline on behalf of the Konus-Wind team,

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

K. Yamaoka, M. Ohno, Y. Fukazawa, T. Takahashi, M. Tashiro,
Y. Terada, T. Murakami, K. Makishima, and Y. Hanabata on
behalf of the Suzaku-WAM team,

and K. Hurley for the IPN

At 16:11:12 on 2009-08-23, GRB 090823 triggered the
Suzaku WAM.  The IPN was notified, and the burst was
also observed by KONUS-Wind, Agile-MCAL, and (during a
slew maneuver) Swift-BAT. A source was found in ground
analysis of BAT event data, which is routinely collected
during many pre-planned slews, and the source location
was confirmed by IPN triangulation.

The BAT position is RA, Dec 228.711, 60.660 which is
equivalent to

      RA, Dec (J2000): 15:14:50.6,  60d 39' 36"

with an uncertainty radius of 4 arcmin (estimated 90%
containment, stat+sys).

We have triangulated GRB 090823 to a Konus-WAM annulus
centered at RA(2000)=141.472 (09h 25m 53s)
Dec(2000)=+9.275 (+9d 16' 31"), whose radius is
52.640  4.346 deg (3 sigma). The BAT source is
0.384 deg (0.27 sigma) from the center line of the
annulus.

As observed in Suzaku-WAM and Agile-MCAL, the burst had
two peaks at about T+1 and T+4 seconds, and had emission
above 700 keV but not above 1.4 MeV. The BAT lightcurve
shows that the emission began with a slow rise beginning
about T-3 seconds, and decayed back to background rates
by about T+20 seconds. The BAT event data, from which
mask-weighted spectra and images are constructed, began
at about T+10.5 seconds, missing 99% of the burst.

A Swift Target of Opportunity has been requested and
approved to follow up this burst with the Swift XRT and
UVOT about 32 hours after the burst.


GRB_name: GRB090823A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9836
SUBJECT: Konus-Wind observations of GRB 090823
DATE:    09/08/25 10:11:26 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

The long GRB 090823 (Cummings et al., GCN 9835)
triggered Konus-Wind at T0=58270.606 s UT (16:11:10.606)
This burst was also observed by the Suzaku WAM, Agile-MCAL, and
(during a slew maneuver) Swift-BAT.

The burst had a smooth structure with a duration of ~10 s.
The Konus-Wind light curves of this GRB are available at
http://www.ioffe.ru/LEA/GRBs/GRB090823_T58270/

As observed by Konus-Wind the burst had
a fluence of 8.9(-0.3,+0.5)x10-6 erg/cm2, and
a 256-ms peak flux, measured from T0+3.072,
of 2.8(-0.25,+0.25)x10-6 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).

The time-integrated spectrum of the burst (from T0 to T0+14.848 s)
is well fitted (in the 20 keV - 2 MeV range)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with Alpha = -0.49(-0.15,+0.17),
and  Ep = 188(-15,+18)keV (chi2 = 56/61 dof).
Fitting by the GRB (Band) model yields to the same Alpha and Ep
values with the high energy photon index Beta of -7 (< -2.7)

The spectrum at the maximum count rate, measured from
T0 + 0.256s to T0 + 6.656s, is well fitted (in the 20 keV - 2 MeV range)
by the GRB (Band) model with:
Alpha = -0.45(-0.14,+0.16),
Beta  = -3.0(-2.2,+0.4), and
Ep    = 182(-18,+18)keV (chi2 = 63/60 dof).

All the quoted values are preliminary.
All the quoted errors are at the 90% confidence level.


GRB_name: GRB090817A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9837
SUBJECT: GRB 090817: No host galaxy, no supernova
DATE:    09/08/25 11:16:13 GMT
FROM:    Jules Halpern at Columbia U.  <jules@astro.columbia.edu>

J. P. Halpern and J. Ruan (Columbia U.) report:

We obtained R-band photometry of the USNO-B1.0 object 341-0096763
on 2009 August 21 10:46 UT using the McGraw Hill 1.3m telescope.
In five 300 s exposures in seeing of 1.5"-1.8", there is no evidence
to support the hypothesis of Holland et al. (GCN Circ. 9831) that this
object is the host galaxy of GRB 090817.  The image is consistent
with the stellar point spread function.  Using the reference star of
Rumyantsev et al. (GCN Circ. 9828), we measure R = 19.39+/-0.04,
consistent with their photometry on Aug. 17.

On Aug. 25 09:56 UT, we again obtained five 300 s exposures in seeing
of 1.5".  We measure R = 19.42+/-0.03, 8.4 days after the burst,
which is consistent with all previous measurements.  Thus, there is
no evidence for brightening suggested by Holland et al. (GCN Circ. 9834)
from Swift UVOT observations between 6.5 and 7.1 days.  The set of
consistent magnitudes from day zero in GCN Circ. 9828 to days 4 and 8
in this report are indicative of a chance coincidence with a normal star.


GRB_name: GRB090823A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9838
SUBJECT: GRB 090823 Correction to BAT position
DATE:    09/08/25 12:56:41 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <jayc@milkyway.gsfc.nasa.gov>

J. R. Cummings (NASA/GSFC/CRESST)

Due to a typographical error, the RA of the source quoted
for GRB 090823 in GCN #9835 was incorrect by a large
amount. The correct BAT position was 128.711, 60.660 which
is equivalent to

     RA, Dec (J2000): 8:34:50.7, 60d 39' 36"

with an uncertainty radius of 4 arcmin (estimated 90%
containment, stat+sys).

I apologize for the error.


GRB_name: GRB090823A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9839
SUBJECT: GRB 090823: Confirmation of Swift-BAT position by BAT Slew Survey
DATE:    09/08/25 19:12:25 GMT
FROM:    Antonio Copete at Harvard U  <acopete@head.cfa.harvard.edu>

A. Copete, J. Grindlay (Harvard)
S. Barthelmy, C. Markwardt, N. Gehrels (NASA/GSFC)

We hereby report confirmation of the Swift-BAT position of GRB 090823  
reported by Cummings et al. (GCN 9835, 9838), from an independent  
analysis of the BAT event-mode data done by the BAT Slew Survey  
(BATSS), in the slew that started at 16:10:02 UT and lasted 178 sec.  
The BATSS-calculated position is RA, Dec = 128.671, +60.641 deg, which  
is:

RA (J2000) =  08h 34m 41s
Dec(J2000) = +60d 38' 29"

with an uncertainty of 4.51 arcmin (90% confidence, including  
systematics). The burst was detected with a significance of 6.2 sigma  
and 6.7 sigma from imaging in the 15-50 keV and 15-150 keV energy  
bands, respectively. Consistent with the report in GCN 9835, the  
lightcurve in the slew data only spans a 15-sec trailing edge of the  
prompt emission of the burst before it fades into the background.


GRB_name: GRB090823A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9840
SUBJECT: GRB 090823: Swift XRT possible detection of the X-ray afterglow 
DATE:    09/08/25 19:20:00 GMT
FROM:    Dirk Grupe at PSU/Swift-XRT  <grupe@astro.psu.edu>

D. Grupe (PSU), E. Hoversten (PSU) and Jay Cummings (NASA/GSFC)
report on behalf of the Swift  team:

We have analysed the XRT and UVOT data of the IPN burst GRB090823
(Cummings et al. GCN Circ. 9835), beginning on 2009-08-24 at
22:17, 30 hours after the Suzaku WAM trigger. The data contain 4.7
ks in XRT  photon counting mode. We clearly detect a possible X-ray
afterglow within the 4' BAT error circle given by Cummings and Copete
et al. (GCN circs. 9838 and 9839, respectively) at
  RA-2000,Dec-2000=128.67676, +60.65169 which corresponds to

RA-2000 = 08h 34m 42.42s
Dec-2000 = +60d 39' 06.1"
with an uncertainty of 5.5"

During the 4.7 ks observation on 2009-08-24 the X-ray source had a
count rate of (5.7+/-1.1)e-3 counts s-1 in the XRT which converts
to an observed flux in the 0.3-10 keV band of (2.9+/-0.5)e-13
ergs s-1 cm-2 assuming a typical GRB afterglow spectrum.


The Swift/UVOT began settled observations of the field of GRB 090823
108380 s after the BAT trigger (Cummings, et al., GCN Circ. 9835).
No optical afterglow consistent with the XRT position
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 initial exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white        109194       115699         1464         >21.8
v               110009       116640         1680         >20.1
u               108380       114954         1597         >20.7

The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.06 in the direction of the burst
(Schlegel et al. 1998).

Swift is planning to re-observe the field of GRB 090823 on
2009-08-27 for 10 ks in order to see if the X-ray source has faded.


This circular is an official product of the Swift team.


GRB_name: GRB090817A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9841
SUBJECT: GRB090817: Keck/LRIS Spectroscopy
DATE:    09/08/26 08:22:47 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko@srl.caltech.edu>

S. B. Cenko, L. M. Walkowicz (UC Berkeley), M. M. Kasliwal, V. Bhalero, S.
R. Kulkarni, F. A. Harrison (Caltech), I. Arcavi (Weizmann Institute) and
W. H. Baumgartner (GSFC/UMBC) report on behalf of a larger collaboration:

We have obtained a spectrum of the putative host galaxy of GRB09817
(Holland et al., GCNs 9831 and 9834) with the Low Resolution Imaging
Spectrometer mounted on the 10 m Keck I telescope.  Our spectra were taken
in twilight conditions at Aug 25.55 UT and cover a wavelength range from
3500 - 9000 A.

After correcting for the large Galactic extinction, the source exhibits
a blue continuum with superposed absorption features from the H Balmer
series (H-alpha, -beta, -gamma, and -delta) and Ca (H+K and the NIR
triplet), all consistent with their rest wavelengths.  As suggested by
Halpern and Ruan (GCN 9837), the object is therefore a foreground star
(likely a hot, ~ A-type) and likely unrelated to GRB090817.


GRB_name: GRB090817A
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9842
SUBJECT: GRB 090817 - TLS Observations
DATE:    09/08/27 00:27:50 GMT
FROM:    Alexander Kann at TLS Tautenburg  <kann@tls-tautenburg.de>

D. A. Kann, F. Cusano and F. Ludwig (TLS Tautenburg) report:

We observed the field of the INTEGRAL/Fermi GRB 090817 (Beckmann et al., 
GCN 9815, Wilson-Hodge, GCN 9823) with the 1.34m Tautenburg Schmidt 
telescope under good conditions. We obtained 3 x 600 sec Rc images at a 
mid-time of 8.015 days after the GRB.

At the position of the X-ray afterglow (Evans, Guidorzi & Baumgartner, 
GCN 9819, GCN 9825), the USNO-B1.0 object 1341-0096763 is clearly 
detected. Using the comparison star of Rumyantsev, Pozanenko & Andreev 
(GCN 9828), we find Rc = 19.54 +/- 0.03 mag. This is in agreement 
with the reports of non-variability (Rumyantsev, Pozanenko & Andreev, 
GCN 9828, Halpern & Ruan, GCN 9837) of this proposed host galaxy/SN 
candidate (Holland, Breeveld & Baumgartner, GCN 9831, GCN 9834), and a 
stellar PSF is in full agreement with it being a foreground star (Halpern 
& Ruan, GCN 9837, Cenko et al., GCN 9841).

No further observations are planned.

This message may be cited.


GRB_name: GRB090828A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9844
SUBJECT: GRB 090828: Fermi GBM detection
DATE:    09/08/28 17:12:22 GMT
FROM:    Sheila McBreen at MPE  <smcbreen@mpe.mpg.de>

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

"At 02:22:48.20  UT on 28 August 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090828 (trigger 273118970 / 090828099 ).

The on-ground calculated location, using the GBM trigger
data, is RA = 124.4, DEC = -26.1 (J2000 degrees,
equivalent to 08 h 18 m, -26 d 06 '), 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 95 degrees.
This burst was also independently detected by INTEGRAL SPI-ACS.

The GBM light curve consists of three pulses
with a duration (T90) of about 100 s (8-1000 keV).
The time-averaged spectrum from T0-0 s to T0+103 s is
well  fit by
a Band function with Epeak = 136.5 (+16.0/-13.7) keV,
alpha = -1.23 (+0.06/-0.05), and beta = -2.12 (+0.08/-0.11)
(chi squared 549 for 485 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(2.52 +/- 0.08)E-5 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+52.2 s in the 8-1000 keV band
is 16.2 +/- 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: GRB090826A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9845
SUBJECT: GRB 090826: Fermi GBM detection
DATE:    09/08/28 20:27:44 GMT
FROM:    Charles Meegan at NASA/MSFC  <charles.a.meegan@nasa.gov>

Charles Meegan (USRA) reports on behalf of the Fermi GBM Team: 

"At 01:37:31.85 UT on 26 August 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090826 (trigger 272943453 / 090826068).

The on-ground calculated location, using the GBM trigger
data, is RA = 140.6, DEC = -0.1 (J2000 degrees,
equivalent to 09 h 22 m, -0 d 6'), with an uncertainty
of 9.7 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 35 degrees.

The GBM light curve consists of two pulses
with a duration (T90) of about 8.5 s (8-1000 keV).
The time-averaged spectrum from T0-4.096 s to T0+9.216 s is
well fit by a power law function with an exponential
high energy cutoff.  The power law index is -0.96 (+0.32/-0.28)
and the cutoff energy, parameterized as Epeak, is
172 (+132/-64) keV (chi squared 232.84 for 241 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(1.26 +/- 0.27)E-6 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+7.168 s in the 8-1000 keV band
is 3.28 +/- 0.35 ph/s/cm^2.

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


GRB_name: GRB090827A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9846
SUBJECT: GRB 090827 Burst discovered in BAT ground analysis
DATE:    09/08/28 20:39:11 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <jayc@milkyway.gsfc.nasa.gov>

J. R. Cummings (GSFC/UMBC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC/UMD), and D. M. Palmer (LANL),
on behalf of the Swift-BAT team

At 19:06:26 on 2009-08-27, GRB 090827 triggered Swift-BAT
(trigger #361029). No source was found onboard.  A source
was found in ground analysis of BAT event data.  The burst
consisted of a single pulse of 7 seconds.  This burst also
triggered Konus-Wind and INTEGRAL-SPI-ACS (V. Pal'shin,
private communication).

The BAT position is RA, Dec 18.435, -50.899, which is
equivalent to:

       RA, Dec (J2000): 01:13:44.4, -50d 53' 58"   

with an uncertainty radius of 2.8 arcmin (estimated 90%
containment, stat+sys). The source was 3% coded.

Because of the extreme partial coding, the spectral parameters
can be defined only poorly.  The spectrum is best fit by a
simple powerlaw relation.  The photon index is 1.0 +/- 0.3.
The fluence was (4 +/- 2) x 10^-6 ergs/cm2. The errors are
estimated 1-sigma.

A Swift TOO has been requested and will take place
starting approximately 26 hours after the burst.


GRB_name: GRB090827A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9847
SUBJECT: GRB 090827: Swift XRT and UVOT observations
DATE:    09/08/29 09:38:48 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

P.A. Evans (U. Leicester) and S.R. Oates (MSSL-UCL) report on behalf of
the Swift team:

The Swift-XRT observed the field of GRB 090827 (Cummings et al. GCN
Circ. 9846), gathering 7.1 ks of Photon Counting (PC) mode data from
T0+92 ks to T0+122 ks. Inside the BAT error circle we find a single,
uncatalogued source at a location of RA,Dec = 18.4495, -50.8957 which is
equivalent to:

RA (J2000)  = 01h 13m 47.88s
Dec (J2000) = -50d 53' 44.0"

with an uncertainty of 6.4 arcsec (radius, 90% condfidence).
There are only 14 counts detected from this source, giving it a count
rate of (3+/-1) x 10^-3 ct/sec. It is impossible to say whether this
source is fading.

A spectrum formed from all available data can be well fitted using an
absorbed power law, with a photon index of 1.6 (+0.9, -0.8) and  an
absorption column density consistent with the Galactic value of 1.6 x
10^20 cm^-2 (Kalberla et al. 2005).

The Swift-UVOT began settled observations of the field 91.6 ks after the
BAT trigger. We do not detect any source at the XRT position.

The 3-sigma upper limits for the finding chart exposure is:

Filter   T_start(s)   T_stop(s)   Exp(s)  Mag (3-sigma upper limit)
-------------------------------------------------------------
U         91644        120333      5671        > 21.94
-------------------------------------------------------------

The quoted upper limits have not been corrected for the expected
Galactic extinction along the line of sight of E_(B-V) = 0.01 mag.
All photometry is on the UVOT photometric system described in Poole et
al. (2008, MNRAS, 383, 627).

This circular is an official product of the Swift team.


GRB_name: GRB090827A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9848
SUBJECT: Konus-Wind observations of GRB 090827
DATE:    09/08/30 15:23:12 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

The long GRB 090827 (Cummings et al., GCN 9846)
triggered Konus-Wind at T0=68787.702 s UT (19:06:27.702)

The burst time profile had a FRED-like structure with a duration of ~8 s.
The Konus-Wind light curves of this GRB are available at
http://www.ioffe.ru/LEA/GRBs/GRB090827_T68787/

As observed by Konus-Wind the burst had
a fluence of 3.0(-0.5,+0.6)x10-6 erg/cm2, and
a 256-ms peak flux, measured from T0-0.256,
of 1.7(-0.5,+0.7)x10-6 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).

The time-integrated spectrum of the burst (from T0 to T0+8.848 s)
is well fitted (in the 20 keV - 2 MeV range)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.6(-0.45,+0.58),
and  Ep = 200(-39,+69)keV (chi2 = 62/57 dof).

Fitting by the GRB (Band) model yields the same alpha and Ep
values with the high energy photon index Beta of -9 (< -2.3)

All the quoted values are preliminary.
All the quoted errors are at the 90% confidence level.


GRB_name: GRB090829A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9849
SUBJECT: GRB090829: Fermi GBM Detection
DATE:    09/08/31 01:54:07 GMT
FROM:    Colleen A. Wilson at NASA/MSFC/NSSTC  <colleen.wilson@nasa.gov>

Colleen A. Wilson-Hodge reports on behalf of the Fermi GBM Team:

"At 16:07:38.86 UT on 29 August 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090829 (trigger 273254860 / 090829672).

The on-ground calculated location, using the GBM trigger data, is
RA = 329.2, DEC = -34.2 (J2000 degrees, equivalent to 21 h 57 m, 34 d 11'),
with an uncertainty of 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 47 degrees.
This burst triggered an automatic repoint of Fermi.

The GBM light curve, with a duration (T90) of about 85 s (8-1000 keV),
consists of a weak precursor followed by a bright peak. The
time-averaged spectrum from T0-6.1 s to T0+92 s is adequately fit by
a Band function with Epeak = 183 +/- 31 keV, alpha = -1.44 +/- 0.04,
and beta = -2.1 +/- 0.1

The event fluence (8-1000 keV) in this time interval is
(1.02 +/- 0.02)E-4 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+46 s in the 8-1000 keV band is 51.5 +/- 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: GRB090831A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9850
SUBJECT: GRB 090831: Fermi GBM detection
DATE:    09/08/31 10:11:30 GMT
FROM:    Arne Rau at MPE  <arau@mpe.mpg.de>

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

"At 07:36:36.58 UT on 31 August 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090831 (trigger 273396998 / 090831317).

The on-ground calculated location, using the GBM trigger
data, is RA = 145.1, DEC = 51.0 (J2000 degrees,
equivalent to 09 h 40m m, +51 d 00 '), with an uncertainty
of 1.9 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 107 degrees.

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

The GBM light curve consists of two structured main pulses
with a duration (T90) of about 69.1 s (8-1000 keV).
The time-averaged spectrum from T+0.0 s to T0+47.7 s is
best fit by a power law function with an exponential
high energy cutoff.  The power law index is -1.57 +/- 0.03 and
the cutoff energy, parameterized as Epeak, is 399.6 +/- 86.2 keV
(chi squared 443 for 415 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(1.66 +/- 0.05)E-05 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+8.784 s in the 8-1000 keV band is 9.4 +/- 0.4 ph/s/cm^2.

A Band function fits the spectrum equally well (chi squared 441 for 414 
d.o.f.)
with Epeak= 243.8 +/- 85.3 keV, alpha = -1.52 +/- 0.06 and beta = -1.96 
+/- 0.14.

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


GRB_name: GRB090831B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9851
SUBJECT: GRB 090831B: Swift detection of a possible burst
DATE:    09/08/31 18:26:54 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

M. De Pasquale (UCL-MSSL), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), D. N. Burrows (PSU),
P. A. Evans (U Leicester), S. T. Holland (CRESST/USRA/GSFC),
J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA),
C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC),
C. Pagani (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL),
P. Romano (INAF-IASFPA), M. Stamatikos (OSU/NASA/GSFC),
R. L. C. Starling (U Leicester) and T. N. Ukwatta (GSFC/GWU) report
on behalf of the Swift Team:

At 18:01:14 UT, the Swift Burst Alert Telescope (BAT) triggered and
located possible GRB 090831B (trigger=361477).  Swift slewed immediately 
to the location.  The BAT on-board calculated location is 
RA, Dec 3.619, +27.970 which is 
   RA(J2000)  =  00h 14m 29s
   Dec(J2000) = +27d 58' 12"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows nothing significant
as is typical for an image trigger. 

The XRT began observing the field at 18:03:44.9 UT, 149.9 seconds after
the BAT trigger. No source was detected in the promptly available XRT
data. We are waiting for the full dataset to detect and localise the
XRT counterpart. 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 153 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. 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. 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
0.03. 

Due to the lack of detection by XRT, we cannot confirm
that this is a true astrophysical source.  Further analysis
of the downlinked data (available in ~3 hours) will be required. 

Burst Advocate for this burst is M. De Pasquale (mdp 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: GRB090831A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9852
SUBJECT: GRB 090831: MAXI GSC detection
DATE:    09/08/31 19:22:52 GMT
FROM:    Nobuyuki Kawai at Tokyo Tech  <nkawai@hp.phys.titech.ac.jp>

M. Matsuoka (JAXA), S. Miyoshi, M. Nakajima, H. Negoro, R. Ishiwata (Nihon
Univ.), K. Kawasaki, S. Ueno, H. Tomida, M. Suzuki, M. Ishikawa (JAXA),
T. Mihara, M. Kohama, Y.E. Nakagawa, M. Sugizaki, T. Yamamoto (RIKEN), 
N. Kawai, M. Morii, K. Sugimori (Tokyo Tech), A. Yoshida, K. Yamaoka, 
S. Nakahira (Aoyama G. Univ.), H. Tsunemi, M. Kimura (Osaka Univ.), 
Y. Ueda, N. Isobe, S. Eguchi and K. Hiroi (Kyoto Univ.) report on behalf of
the MAXI team:

The Gas Slit Camera (GSC) of MAXI, the all-sky X-ray monitor on the ISS,
detected a bright X-ray source at the position consistent with GRB 090831
(Rau et al, GCN 9850) in the energy range of 2-30 keV.  
The nominal location of the source as measured by GSC is 

(R.A., Dec.) = (145.4 deg, +51.4 deg) = (09:41:36, +51:24:00) (J2000)

with an estimated systematic uncertainty of about 1 degree.

The source was detected for 60 seconds during the transit of GSC over 
the source starting approximately at 07:36:35 UT on 31 August 2009, 
very close to the Fermi GBM trigger time.
The X-ray flux at the peak of the transit was about 3 Crab.
There are significant time structure within the transit light curve, 
which would be simply triangular for a steady source.

The all-sky image and the transit light curve is shown at the MAXI web site
http://maxi.riken.jp/ in the "News" section.

MAXI is currently in the commissioning phase that runs for three months.
The systematic uncertainty in localization will be significantly improved
with the progress of the alignment calibration.


GRB_name: GRB090831B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9853
SUBJECT: GRB 090831B, RIMOTS optical upper limits
DATE:    09/08/31 20:02:34 GMT
FROM:    Kenta Kono at Miyazaki U  <kenta0514@astro.miyazaki-u.ac.jp>

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

We have observed the field covering the error circle of
GRB 090831B (Swift trigger 361477, GCN 9851, M. De Pasquale et al.)
with the unfiltered CCD camera on the 30-cm telescope
at University of Miyazaki.
The observation was started 18:03:42 UT, about 2.5 min
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 9851, M. De Pasquale et al.)

the upper limits are as follows:
--------------------------------------------------------------
Start(UT) End(UT) Num. of frames Limit (mag.)
--------------------------------------------------------------
18:03:42    18:04:12         1            15.4
18:03:42    18:40:05        27            17.2
---------------------------------------------------------------


GRB_name: GRB090831C
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9854
SUBJECT: GRB 090831C: Swift detection of a burst
DATE:    09/08/31 21:42:30 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

P. Schady (MSSL-UCL), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester),
J. R. Cummings (NASA/UMBC), P. A. Evans (U Leicester),
C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC),
J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA),
C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC),
C. Pagani (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL),
A. Rowlinson (U Leicester), M. H. Siegel (PSU),
M. Stamatikos (OSU/NASA/GSFC) and M. A. Stark (PSU) report on behalf
of the Swift Team:

At 21:30:25 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090831C (trigger=361489).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 108.278, -25.100 which is 
   RA(J2000)  =  07h 13m 07s
   Dec(J2000) = -25d 06' 00"
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 ~800 counts/sec (15-350 keV), at ~3 sec after the trigger. 

The XRT began observing the field at 21:32:23.5 UT, 117.5 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source located at RA, Dec 108.29307, -25.11934 which
is equivalent to:
   RA(J2000)  = 07h 13m 10.34s
   Dec(J2000) = -25d 07' 09.6"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 85 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
3.24e+21 cm^-2 (Kalberla et al. 2005). 


UVOT took a finding chart exposure of 150 seconds with the White filter
starting 120 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. Results from the 2.7'x2.7' sub-image
are not available at this time. The coverage of the XRT error circle by the
8'x8' region for the list of sources generated on-board is uncertain because
the large number of sources filled the available telemetry. No correction has
been made for the expected extinction corresponding to E(B-V) of 0.38. 




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: GRB090831C
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9855
SUBJECT: GRB 090831C: Enhanced Swift-XRT position
DATE:    09/09/01 02:31:50 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 3607 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 090831C, 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 = 108.29453, -25.11859 which is equivalent
to:

RA (J2000): 07h 13m 10.69s
Dec (J2000): -25d 07' 06.9"

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: GRB090829B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9856
SUBJECT: GRB 090829B: Fermi GBM Detection
DATE:    09/09/01 02:58:06 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 16:50:40.13 UT on 29 August 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090829B (trigger 273257442 / 090829702).

The on-ground calculated location, using the GBM trigger data, is
RA = 355.0, DEC = -9.4 (J2000 degrees, equivalent to 23 h 40 m, -9 d 22'),
with an uncertainty of 3.2 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 42 degrees.

The GBM light curve consists of two widely spaced peaks with a duration
(T90) of about 100 s (8-1000 keV). The time-averaged spectrum from
T0-1.5 s to T0+31.2 s is best fit by a Band function with
Epeak = 143 +/- 30 keV, alpha = -0.7 +/- 0.2, and beta = -2.4 +/- 0.5

The event fluence (8-1000 keV) in this time interval is
(6.4 +/- 0.7)E-6 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+4.6 s in the 8-1000 keV band is 3.2 +/- 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: GRB090831C
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9857
SUBJECT: GRB 090831C: Swift XRT Refined Analysis
DATE:    09/09/01 07:03:06 GMT
FROM:    Antonia Rowlinson at U.of Leicester  <bar7@star.le.ac.uk>

A. Rowlinson (U. Leicester) and P. Schady (MSSL-UCL) report on behalf of
the Swift-XRT team:

We have analysed 8.4 ks of XRT data for GRB 090831C (Schady et al. GCN
Circ. 9854), from 121 s to 21.8 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 9855).

The light curve has two flares at T+186 s and T+440 s, while the
underlying decay can be modelled with a power-law decay with a decay
index of alpha=0.83 (+0.17, -0.11).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.84 (+0.21, -0.15). The
best-fitting absorption column is 3.254 (+1.001, -0.014) x 10^21 cm^-2,
consistent with the Galactic value of 3.2 x 10^21 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 (7.2 x 10^-11) erg
cm^-2 count^-1.

If the light curve continues to decay with a power-law decay index of
0.83, the count rate at T+24 hours will be 0.0029 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.4 x
10^-13 (2.1 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/00361489.

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


GRB_name: GRB090831B
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9858
SUBJECT: GRB 090831B: MITSuME optical upper limits
DATE:    09/09/01 09:35:30 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 090831B (De Pasquale et al. GCN
9851) 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 2009-08-31 18:03:21 UT
(2m 7s after the burst). We did not find any new point source
in the BAT error circle reported by De Pasquale et al. (GCN 9851)
in all the three bands.

Three sigma upper limits of the OT are listed below. We used
GSC2.3 catalog for flux calibration.

#PDAY      MID-UT   T-EXP      g'     Rc      Ic
--------------------------------------------------
0.00505  18:09:49    540.0   >19.0   >18.8   >18.1
0.03482  18:52:41   4200.0   >19.9   >19.7   >19.0
--------------------------------------------------


GRB_name: GRB090831C
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9859
SUBJECT: GRB090831C: Swift/UVOT upper limits
DATE:    09/09/01 10:42:09 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 090831C 121s 
after the BAT trigger (Schady et al., GCN Circ 9854). No new source is 
detected within the XRT error circle (Evans et al., GCN Circ 9855) in any 
of the individual or combined UVOT filters.

The 3-sigma upper limits of detecting a source at the position of the 
X-ray afterglow in the first white band finding chart (fc) observation and 
in consecutive coadded observations for each of the UVOT filters are as 
follows:

Filter T_start(s) T_stop(s) Exp(s) Mag 3-sig UL
wh (fc)    121       270     147      > 20.78
wh         561       1183    206      > 20.73
vv         610       1060    58       > 18.47
bb         536       1159    58       > 19.30
uu         279       1134    285      > 19.95
w1         660       1109    58       > 18.74
m2         635       1084    58       > 18.48
w2         586       1209    78       > 18.95


The values quoted above are not corrected for the Galactic extinction due 
to the large reddening of E(B-V) = 0.38 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: GRB090831B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9860
SUBJECT: Swift Trigger 361477, called GRB090831B, is probably not real.
DATE:    09/09/01 12:45:04 GMT
FROM:    Massimiliano de Pasquale at MSSL-UCL  <mdp@mssl.ucl.ac.uk>

J.R. Cummings (NASA/UMBC), P.A. Evans (U. Leicester), J.A. Kennea (PSU), 
C. Pagani (PSU), and M. De Pasquale (MSSL/UCL) on behalf of the Swift 
team report:

The ground analysis of BAT data from trigger 361477 (De Pasquale et al., 
GCN Circ. 9851) shows a very weak excess in the low energy bands only. 
The response is consistent with a somewhat unusually large noise 
fluctuation in the image domain caused by the presence of a bright source 
in the BAT partially coded field of view (Cyg-X1).

The XRT observed the field for 3.23 ks between T0+150 s and T0+10 ks. The 
data are entirely in Photon Counting mode. We do not find any source in 
the field of view. A 3-sigma upper limit on covering the BAT onboard error 
circle is 2.7 x 10^-3 ct/sec.

  No new source is found in the UVOT white filter finding chart (153-303s 
after the trigger) inside the BAT error circle down to a 3 sigma upper 
limit of 20.9.

  We conclude that the trigger is unlikely to be due to a GRB or any other 
astrophysical source.


GRB_name: GRB090831A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9861
SUBJECT: Konus-Wind observations of GRB 090831A
DATE:    09/09/01 13:40:48 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

GRB 090831A (Rau, GCN 9850; Matsuoka et al., GCN 9852)
triggered Konus-Wind at T0=27393.820 s UT (07:36:33.820)

The burst started with a short (~250 ms) spike which resembles
a classical short/hard GRB. The spike is followed by a structured
profile with a total duration of ~50 s.
The Konus-Wind light curves of this GRB are available at
http://www.ioffe.ru/LEA/GRBs/GRB090831_T27393/

As observed by Konus-Wind, the burst had
a fluence of 1.33(-0.2,+0.25)x10-5 erg/cm2, and
a 16-ms peak flux, measured from T0,
of 9.3(-2.2,+3.2)x10-6 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).

The time-integrated spectrum of the burst (from T0 to T0+49.408 s)
is well fitted (in the 20 keV - 2 MeV range)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep), with
alpha = -1.53(-0.14,+0.16),  and
Ep = 253(-69,+162)keV (chi2 = 69/61 dof).
Fitting by the GRB (Band) model yields to the same alpha and Ep
values with the high energy photon index beta of -9 (< -2.1)

The spectrum at the maximum count rate,
measured from T0 to T0 + 0.256s  (initial short pulse),
is well fitted (in the 20 keV - 2 MeV range)
by the GRB (Band) model with:
alpha = -1.28(-0.3,+0.7),
beta  = -2.5( < -1.7), and
Ep    = 273(-212,+331)keV (chi2 = 12/22 dof).

All the quoted values are preliminary.
All the quoted errors are at the 90% confidence level.


GRB_name: GRB090831C
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9862
SUBJECT: GRB 090831C: GROND upper limits
DATE:    09/09/01 18:45:16 GMT
FROM:    Thomas Kruehler at MPE/MPI  <kruehler@mpe.mpg.de>

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

We observed the field of GRB 090831C (Swift trigger #361489; Schady et al., 
GCN #9854) 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 LaSilla 
Observatory (Chile).

Observations started at 08:07 UT on September 1st, 2009, 10.6 hr after the 
burst. At this time the position of the burst was becoming visible above 
the pointing constraints of the telescope. Observations suffer from high 
airmass and large seeing of around 2". In stacked images of 74 min total 
integration time in griz and 60 min in JHK, we do not detect any object 
within the enhanced XRT error circle (Evans et al., GCN #9855), down to the 
following limiting magnitudes (all in the AB system):

g' > 23.5
r' > 24.0
i' > 23.3
z' > 22.9
J > 21.4
H > 21.1
K > 20.0

These upper limits were derived using the GROND zeropoints and 2MASS field 
stars as reference and are not corrected for significant Galactic 
foreground extinction corresponding to a reddening of E(B-V)=0.38 mag 
(Schlegel et al., 1998).


GRB_name: GRB090831C
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9863
SUBJECT: GRB 090831C BAT refined analysis
DATE:    09/09/02 01:30:11 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <jayc@milkyway.gsfc.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), P. Schady (MSSL-UCL), M. Stamatikos (OSU),
J. Tueller (GSFC), T. N. Ukwatta (GWU)
(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 090831 (trigger #361489)
(Schady, et al., GCN Circ. 9854).  The BAT ground-calculated position is
RA, Dec = 108.294, -25.112 deg which is
    RA(J2000)  =  07h 13m 10.6s
    Dec(J2000) = -25d 06' 44.0"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 84%.

The mask-weighted light curve shows a single roughly symmetrical peak.
T90 (15-350 keV) is 3.3 +- 1.0 sec (estimated error including systematics).

The time-averaged spectrum from T+0.6 to T+4.9 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.33 +- 0.29.  The fluence in the 15-150 keV band is
1.5 +- 0.3 x 10^-07 erg/cm2.  The 1-sec peak photon flux measured from
T+1.94 sec in the 15-150 keV band is 0.5 +- 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/361489/BA/


GRB_name: GRB090831A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9864
SUBJECT: GRB 090831A: IPN Triangulation
DATE:    09/09/02 04:31:29 GMT
FROM:    Valerie Connaughton at MSFC  <valerie@nasa.gov>

S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and T.
Cline on behalf of the Konus-Wind team,

V. Connaughton, M. Briggs, and C. Meegan, on behalf of the Fermi GBM
team,

K. Yamaoka, M. Ohno, Y. Fukazawa, T. Takahashi, M. Tashiro, Y. Terada,
T. Murakami, K. Makishima, and Y. Hanabata on behalf of the Suzaku-WAM
team,

M. Suzuki, A. Yoshida, N. Kawai, S. Nakahira, Y.E.  Nakagawa, M. Kohama
and M. Matsuoka on behalf of the MAXI team

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

GRB 090831A, reported in GCN 9850 (Rau)  as Fermi/GBM trigger
273396998 / 090831317,  and as a MAXI event  in GCN 9852 (Matsuoka et al.),
and as a Konus event in GCN 9861 (Golenetskii et al.), was also detected by
Suzaku-WAM and INTEGRAL (SPI-ACS).

We have triangulated this burst to a Konus-GBM annulus centered at
RA(2000)=155.584 (10h 22m 20s) Dec(2000)=+3.772 (+3d 46' 21"),
with a radius of 49.244  0.177 deg (3 sigma).

The Konus-WAM  annulus is centered at
RA(2000)=155.807 (10h 23m 14s)  Dec=+3.771 (+3d 46' 16"), with a
radius of 49.210  0.249 deg (3 sigma).

The Konus-SPI-ACS annulus is centered at
RA(2000)=156.539 (10h 26m  09s)  Dec(2000)=-3.361 (-3d 21' 41"), with
radius of 56.520  0.412 deg (3 sigma).

A map is posted at http://www.ioffe.ru/LEA/GRBs/GRB090831_T27393/IPN/
showing the GBM best-fit position (blue star), the MAXI localization circle
and best-fit position (pink star), and the IPN annuli (solid lines with
centers dot-dashed). The shaded area shows the intersection of the
Konus-GBM annulus with the 1-deg MAXI localization circle.
The maximum distance between points on this overlapping region is 1.47 deg,
at coordinates RA, Dec = 143.985 (09h 35m 56s) +51.878 (+51d 52'
40") and 146.304 (09h 45m 13s)   +52.229 (+52d 13' 46").
The area of this region is 0.160 sq. deg.

This map will also be posted at http://ssl.berkeley.edu/ipn3/090831A.

The IPN localization may be improved.


GRB_name: GRB090902A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9865
SUBJECT: GRB 090902: Fermi GBM detection
DATE:    09/09/02 16:44:07 GMT
FROM:    Elisabetta Bissaldi at MPE  <ebs@mpe.mpg.de>

E. Bissaldi and A. von Kienlin (MPE)
report on behalf of the Fermi GBM Team: 


"At 09:38:05.49 UT on 2 September 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090902 (trigger 273577087 / 090902401).
The on-ground calculated location, using the GBM trigger
data, is RA = 291.0, DEC = 53.1 (J2000 degrees,
equivalent to 19h 24m, 53d 06'), with an uncertainty
of 3.8 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 82 degrees.

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

The GBM light curve consists of a single peak
with a duration (T90) of about 1.2 s (8-1000 keV).
The time-averaged spectrum from T0-0.256 s to T0+0.896 s is
best fit by a Band function with Epeak = 388 (+82/-102) keV,
alpha = 0.30 (+0.5/-0.26), and beta = -2.05 (+0.29/-0.24)
(chi squared 372 for 356 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(2.11 +/- 0.14)E-06 erg/cm^2. The 64-msec peak photon flux measured
starting from T0+608 s in the 8-1000 keV band
is 11.4 +/- 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: GRB090902B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9866
SUBJECT: GRB 090902B: Fermi GBM detection of a bright burst
DATE:    09/09/02 21:19:03 GMT
FROM:    Elisabetta Bissaldi at MPE  <ebs@mpe.mpg.de>

Elisabetta Bissaldi (MPE) and Valerie Connaughton (UAH)
report on behalf of the Fermi GBM Team: 


"At 11:05:08.31 UT on 2 September 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090202B (trigger 273582310 / 090902462).
The on-ground calculated location, using the GBM trigger
data, is RA = 264.5, DEC = 26.5 (J2000 degrees,
equivalent to 17h 38m, 26d 30'), with an uncertainty
of 1.0 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 52 degrees.
Moreover, this burst was bright enough to result in
a Fermi spacecraft repointing maneuver.

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

The GBM light curve consists of a bright pulse
with a duration of about 21 s.
The time-averaged spectrum between 50 keV and 40 MeV
from T0 to T0+22 s is well fit by a Band function
with Epeak = 775 +/- 11 keV, alpha = -0.696 +/- 0.012 
and beta = -3.85 (+0.21/-0.31).

The event fluence (50 keV - 10 MeV) in this time interval is
(3.74 +/- 0.03)E-04 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+14 s in the 50 keV - 10 MeV band
is 46.1 +/- 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: GRB090902B
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9867
SUBJECT: GRB 090902B: Fermi LAT detection
DATE:    09/09/02 22:48:18 GMT
FROM:    Hiroyasu Tajima at SLAC  <htajima@slac.stanford.edu>

Francesco de Palma (Universit e INFN Bari), Johan Bregeon (INFN,  
Pisa) and Hiro Tajima (SLAC) report on behalf of the Fermi LAT team:

At 11:05:15 UT on 2 Sep 2009, the Fermi Large Area Telescope (LAT)  
detected gamma rays from the long GRB 090902B, which was triggered and  
located by the Fermi Gamma-ray Burst Monitor (GBM) (trigger  
273582310/090902462, GCN9866). The angle of the GBM best position (RA,  
Dec= 264.5, 26.5) with respect to the LAT boresight was 51 degrees at  
the time of the trigger, which is close the edge of our field of view.

The data from the Fermi LAT show a significant increase in the event  
rate within 1 degree of the GBM location after the GBM trigger that is  
spatially and temporally correlated with the GBM emission with high  
significance. More than 200 photons above 100 MeV and more than 30  
photons above 1 GeV are observed within 100 seconds. The highest  
energy photon is a 33.4 GeV event which is observed 82 seconds after  
the GBM trigger.

The best LAT on-ground localization is found to be (RA,Dec=265.00,  
27.33) with a 90% containment radius of 0.06 deg (statistical; 68%  
containment radius: 0.04 deg, preliminary systematic error is less  
than 0.1 deg) which is consistent with the GBM localization. A Swift  
TOO request has been issued.

Further analysis is ongoing.

The point of contact for this burst is

Francesco de Palma (francesco.depalma@ba.infn.it)


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: GRB090902B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9868
SUBJECT: GRB 090902B: Swift/XRT Afterglow Candidate
DATE:    09/09/03 03:00:57 GMT
FROM:    Jamie A. Kennea at PSU/Swift-XRT  <kennea@astro.psu.edu>

J. A. Kennea (PSU) and G. Stratta (ASDC) report on behalf of the Swift/XRT 
team:

At 23:36 UT, September 2nd, 2009, Swift began a Target of Opportunity 
observation of the Fermi GBM/LAT discovered burst GRB 090902B (de Palma et 
al., GCN #9867, Bissaldi et al., GCN #9866), approximately 12.5 hours 
after the Fermi detection. In early data we detect an uncatalogued point 
source at the following location, RA, Dec = 264.93984, 27.32405, which is 
equivalent to:

RA (J2000) = 17h 39m 45.6s
Dec (J2000) = +27d 19' 26.6''

with an estimated uncertainty of 4.2 arcseconds radius (90% confidence). 
This position is 3.2 arcmin from the reported LAT position, inside the LAT 
error radius.

At this time we cannot confirm if the point source is fading. Observations 
of this field are on-going.


GRB_name: GRB090902B
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9869
SUBJECT: GRB090902B: Swift/UVOT observations
DATE:    09/09/03 04:57:44 GMT
FROM:    Craig Swenson at PSU/Swift  <cswenson@astro.psu.edu>

C. A. Swenson (PSU) and M. H. Siegel (PSU) report on behalf of the Swift
UVOT team:

The Swift/UVOT began observations of the field of GRB090902B
approximately 12.5 hours after the Fermi GBM/LAT trigger (de Palma et
al., GCN #9867, Bissaldi et al., GCN #9866).  Within the initial 4.2"
XRT error circle (Kennea et al., GCN #9868) we find a very faint source:

Filter    T_start(s)    T_stop(s)    Exp(s)      Mag

u         273627410     273634846     2691     20.41 +- 0.20 (5.5-sigma)

This source does not seem to appear in the DSS; however, its proximity
to another DSS source, also within the XRT error circle, makes
identifying this source as the afterglow difficult.  We await an
enhanced XRT position and/or ground-based detection to confirm the
nature of this potential afterglow candidate.

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: GRB090902B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9870
SUBJECT: GRB 090902B: Optical afterglow candidate
DATE:    09/09/03 05:30:08 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>

D. A. Perley, I. K. W. Kleiser, and J. M. Rex (UC Berkeley) report:

We imaged the location of the Swift-XRT candidate afterglow (GCN 9868, 
Kennea et al.) of extremely bright Fermi GRB 090902B (GCN 9866, Bissaldi 
et al.) with the Nickel 1-meter telescope at Lick Observatory.  We 
marginally detect a faint source in individual 600-second exposures at 
the western edge of the XRT error circle with a magnitude comparable to 
the Digitized Sky Survey limit.  This is likely the same source observed 
by the UVOT (GCN 9868, Swenson et al.).

We cannot confirm fading behavior at this time, and further observations 
are encouraged.  A finding chart showing the XRT error circle and the 
putative afterglow is available at the following URL:

http://lyra.berkeley.edu/~dperley/090902b/090902b_lick.jpg


GRB_name: GRB090902B
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9871
SUBJECT: GRB 090902B: Enhanced Swift-XRT position
DATE:    09/09/03 06:25:14 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.

Using 2.7 ks of XRT Photon Counting mode data and 2 UVOT images for GRB 
090902B, 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 = 264.93859, 27.32448 which is equivalent to:

RA (J2000): 17h 39m 45.26s
Dec (J2000): +27d 19' 28.1"

with an uncertainty of 2.1 arcsec (radius, 90% confidence).

Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) 
and Evans et al. (2009, MNRAS, 397, 1177).

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


GRB_name: GRB090902B
Detection_method: Fermi LAT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9872
SUBJECT: GRB 090902B: Fermi LAT and GBM refined analysis.
DATE:    09/09/03 07:36:42 GMT
FROM:    Valerie Connaughton at MSFC  <valerie@nasa.gov>

F. de Palma (Universit e INFN Bari), E. Bissaldi (MPE), H. Tajima (SLAC),
S. Guiriec (UAH),  N. Omodei (INFN Pisa), V. Vasileiou (NASA GSFC/UMBC)
and V. Connaughton (UAH) report for the Fermi LAT and GBM teams:

Further analysis of GRB 090902B (Bissaldi et al. GCN 9866, de Palma et al.
 GCN 9867, Kennea et al. GCN 9868) reveals it is detected in the Fermi
Large Area Telescope (LAT) at least until 300 s after the Fermi
Gamma-Ray Burst Monitor (GBM) trigger time, T0=11:05:08.31 UT.

Spectral analysis of the main emission episode, from T0 to T0+25 s, shows a
deviation from the Band function obtained from fitting GBM data between
50 keV and 40 MeV (GCN 9866). This deviation is apparent both below 50
keV in the GBM and above 100 MeV in the LAT. It is well-fit by a single
power-law, with a well-constrained index that is retrieved from a fit of 
the
GBM data alone, the LAT data alone, and when jointly fitting the entire
data set.

The parameters for this multi-component fit are Band_alpha =
0.61  0.01, Band_beta = 3.87  0.16, Band_EPeak = 798  7 keV,
and a power-law index of 1.94  0.01 that shows no evidence for a
spectral cut-off below 100 GeV. The fluence between 8 keV and 30
GeV is 4.86  0.06 x 10-4 ergs/cm2.

The points of contact for this burst are:

Francesco de Palma (francesco.depalma@ba.infn.it) and
Elisabetta Bissaldi (ebs@mpe.mpg.de).

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: GRB090902B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9873
SUBJECT: GRB 090902B: Gemini-N absorption redshift
DATE:    09/09/03 08:23:17 GMT
FROM:    Antonino Cucchiara at PSU  <cucchiara@astro.psu.edu>

A. Cucchiara, D. B. Fox (PSU), N. Tanvir (U. Leicester),
E. Berger (Harvard U.) report on behalf of a large collaboration.

"On 2009 September 3.27 UT we observed the Fermi/LAT GRB 090902B
(Bissaldi et al., GCN 9866, de Palma 9867) with the Gemini-N
telescope equipped with the GMOS spectrograph.

A single object has been found at the position of the Swift/XRT
afterglow (Kennea et al. GCN 9868, Perley et al., GCN 9870) in
our acquisition image.

A pair of 900 sec exposures spectra were obtained with a wavelength
coverage of 4500-7500A under good conditions.
The spectrum reveals a series of metal absorption features,
MgII[2796,2803], MgI[2853],MnII[2606], FeII[2600], MnII[2594],
FeII[2586], FeII[2260], SiII[1808], SiII*[1816].

All these features are consistent with a redshift of z = 1.822,
which, therefore, we conclude is the redshift of GRB 090902B.


We thank the Gemini-N staff for performing this observation,
in particular Ricardo Schiavon."


GRB_name: GRB090902B
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9874
SUBJECT: GRB 090902B: GROND NIR Afterglow Observations
DATE:    09/09/03 09:14:50 GMT
FROM:    Thomas Kruehler at MPE/MPI  <kruehler@mpe.mpg.de>

F. Olivares, P. Afonso, J. Greiner (all MPE Garching), S. McBreen (MPE + 
UCD), T. Kruehler, A. Rau, A. Yoldas, G. Kanbach (all MPE), and S. Klose 
(TLS Tautenburg) report on behalf of the GROND team:

The field of GRB 090902B, (Fermi GBM trigger 273582310/090902462, Bissaldi 
et al., GCN #9866) which was detected by the LAT (de Palma et al., GCN 
#9867), was observed 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 LaSilla 
Observatory (Chile).

Observations started at 00:21 UT on September 3, 2009, 13.25 hours after 
the GRB trigger. They were performed at a seeing of around 2", at an 
average air mass larger than 2.0 and under variable sky conditions. We 
detect a NIR source within the Swift/XRT error circle reported by Kennea et 
al. (GCN #9868) and on the edge of the Swift/XRT enhanced position (Evans 
et al. GCN #9871), at:

RA (J2000) = 17h 39m 45.41s
DEC (J2000) = +27d 19' 27.1"

with an uncertainty of 0.5" in each coordinate.

This position seems consistent with the object reported by Perley et al. 
(GCN #9870) and is very likely the source reported by Swenson & Siegel (GCN 
#9869).

The source is not in the field of view of the griz channels, so no 
statement can be made about the optical bands.

The afterglow (Cucchiara et al. GCN #9873) has the following preliminary AB 
magnitude and shows tentative evidence of fading within the observations.

midtime         J_AB mag
  -----------------------------------------------
01:09:31 UT     20.26 +/- 0.07

Calibrations was done against 2MASS catalog stars. No Galactic extinction 
correction was applied.


GRB_name: GRB090902B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9875
SUBJECT: GRB 090902B: Faulkes Telescope North observations
DATE:    09/09/03 10:09:22 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

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

On 2009 September 03 at 07:50:02 UT we began observing
the Fermi GRB 090902B (Bissaldi et al., GCN 9866; de Palma
et al. GCN 9867, 9872) with the Faulkes Telescope North
using the R filter.

Within the Swift UVOT-enhanced XRT error circle (Evans et al.
GCN 9871) we clearly detect the afterglow candidate (Swenson et
al. GCN 9869, Perley et al. GCN 9870, Cucchiara et al. GCN 9873,
Olivares et al. GCN 9874) at the following position (J2000):

RA:   17:39:45.35
Dec: +27:19:27.1

with an uncertainty of 0.7". At the mid epoch of 21.01 hours
post burst we measure R=21.03 +- 0.11 mag.
Calibration was performed with the USNOB-1 star RA=17:39:42.74
Dec=+27:19:13.76 assuming R2=17.46.


GRB_name: GRB090902B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9876
SUBJECT: GRB090902B: Swift XRT refined analysis
DATE:    09/09/03 15:30:29 GMT
FROM:    Giulia Stratta at ASDC  <stratta@asdc.asi.it>

G. Stratta, V. D'Elia, M. Perri (ASDC) report on behalf of the
Swift XRT team:

At 23:36 UT, September 2nd, 2009, Swift began a Target of Opportunity
observation of the Fermi GBM/LAT discovered burst GRB 090902B (de
Palma et al., GCN 9867, Bissaldi et al., GCN 9866) about 12.5 hours
after the trigger.

We confirm that the X-ray source reported by Kennea et al. (GCN
Circ. 9868) shows a decaying behavior and is likely the afterglow of
GRB 090902B.

The enhanced XRT position for this burst was given by Evans
(GCN. Circ 9871).

The X-ray light curve from T+12.53 hr to T+17.38 hr can be fit with
a single power-law model with a decay index of -1.3+/-0.9 (90% confidence
level).

With 4.8 ks of integration time, the X-ray spectrum from T+12.53 hr to T+17.38 hr
after the Fermi/GBM trigger can be fit by an absorbed power-law model
with a photon index of 2.1 (+0.3,-0.3) and a rest frame column density of
(3.4+/-0.9) x 10^22 cm^-2 at z=1.822 (Cucchiara et al., GCN 9873)
in addition to the Galactic column density
in the direction of the burst (3.88 x 10^20 cm^-2, Kalberla et al. 2005).
Errors are at 90% confidence level.
The observed 0.3-10.0 keV flux is 3.2 x 10^-12 erg cm^-2 s^-1 which
corresponds to an unabsorbed flux of 4.1 x 10^-12  erg cm^-2 s^-1.

Providing the source continues to decay at the same rate, we predict an
observed flux of about 8.7 x 10^-13 erg cm^-2 s^-1 at T+2 days.

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

[GCN OPS NOTE(03sep09): Per author's request, the missing Cucchiara
reference was added.] 


GRB_name: GRB090902B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9877
SUBJECT: GRB 090902B:  Swift/UVOT refined analysis
DATE:    09/09/03 19:55:45 GMT
FROM:    Craig Swenson at PSU/Swift  <cswenson@astro.psu.edu>

C. A. Swenson (PSU) and G. Stratta (ASDC) report on behalf of the
Swift/UVOT team:

The Swift/UVOT began observations of the field of GRB 090902B
approximately 12.5 hours after the Fermi GBM/LAT trigger (de Palma
et al., GCN Circ. 9867; Bissaldi et al., GCN Circ. 9866).  We can
now confirm the detection of the optical afterglow (Swenson et al.,
GCN Circ. 9869; Perley et al., GCN Circ. 9870; Cucchiara et al.,
GCN Circ. 9873; Olivares et al., GCN Circ. 9874; Guidorzi et al.,
GCN Circ. 9875) coincident with the enhanced Swift-XRT position (Evans,
GCN Circ. 9871).  We also observe a decay in the optical afterglow.

The observed magnitudes using the UVOT photometric system (Poole et
al. 2008, MNRAS, 383, 627) are:

Filter       T_start(s)     T_stop(s)      Exp(s)         Mag

u              45096          46188         1075        20.26  0.19
u              50891          58703         3613        20.50  0.11
u              62457          81106         8756        20.85  0.10

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: GRB090902B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9878
SUBJECT: GRB 090902B: ROTSE-III Detection of Optical Afterglow
DATE:    09/09/03 20:40:17 GMT
FROM:    Shashi Bhushan Pandey at ROTSE  <shaship@umich.edu>

S. B. Pandey, W. Zheng, F. Yuan and C. Akerlof (U Mich), report on behalf
of the
ROTSE collaboration:

ROTSE-IIIa, located at the Siding Spring Observatory Australia, responded ~
283 sec after the GBM trigger 273582310 (Bissaldi E. & Connaughton V. GCNC
9866). The Set of images starting ~ 1.4 hours after the trigger covered the
GRB 090902B location. The OT (Perley et al. GCNC 9870, Kennea & Stratta
GCNC 9868) was detected at 15.9+-0.2 mag in the sum of 30x60 sec exposures.

The images taken by ROTSE-IIIc (located naer the H.E.S.S. site at Mt.
Gamsberg, Namibia) around 6.6 hours after the burst marginally detect the
OT, indicating a decay of ~ 2 magnitudes. The unfiltered images were
calibrated relative to USNO B1.0. Further analysis is in progress.


GRB_name: GRB090904A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9879
SUBJECT: GRB 090904: Swift detection of a burst
DATE:    09/09/04 01:18:05 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

M. Perri (ASDC), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), V. D'Elia (ASDC),
S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),
F. E. Marshall (NASA/GSFC), M. H. Siegel (PSU),
M. Stamatikos (OSU/NASA/GSFC), M. A. Stark (PSU) and
T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:

At 01:01:06 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090904 (trigger=361830).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 100.882, +50.206 which is 
   RA(J2000) = 06h 43m 32s
   Dec(J2000) = +50d 12' 23"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a small peak at T_zero
and then two large peaks at T+130 and T+175 sec with a duration
of at least 200 sec.  The peak count rate
was ~2500 counts/sec (15-350 keV), at ~T+130 sec after the trigger. 

The XRT began observing the field at 01:05:38.6 UT, 271.7 seconds after
the BAT trigger. XRT found a bright, uncatalogued, fading X-ray source located
at RA, Dec 100.8816, +50.2040 which is equivalent to:
   RA(J2000)  = 06h 43m 31.58s
   Dec(J2000) = +50d 12' 14.4"
with an uncertainty of 5.2 arcseconds (radius, 90% containment). This
location is 7.3 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. 

The XRT prompt light curve shows a large flare peaking about 30s 
after the start of the XRT observations. 

The initial flux in the 2.5 s image was 1.71e-09 erg cm^-2 s^-1 (0.2-10
keV). 


UVOT took a finding chart exposure of 150 seconds with the White filter
starting 141 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. Because part of the 2.7'x2.7'
sub-image was not received, the overlap with the XRT error circle is uncertain. 
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
0.10. 




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: GRB090904A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9880
SUBJECT: GRB 090904A: ROTSE-III Optical Limits
DATE:    09/09/04 01:25:32 GMT
FROM:    Shashi Bhushan Pandey at ROTSE  <shaship@umich.edu>

S. B. Pandey (U Mich), W. Rujopakarn (Steward), W. Zheng (U Mich) report on
behalf of the ROTSE collaboration:

ROTSE-IIId, located at the Turkish National Observatory at Bakirlitepe,
Turkey, responded to GRB 090904A (Swift trigger 361830; Perri M., GCN
9879), producing images beginning 9.5 s after the GCN notice time. An
automated response took the first image at 01:02:31.6 UT, 84.7 s after the
burst, and during the gamma-ray emission, under fair conditions. We took 10
5-sec, 10 20-sec and 10 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 or the XRT error circle, for both single
images and coadding into sets of 10. Individual images have limiting
magnitudes ranging from 15.8-16.6; we set the following specific limits.

start UT       end UT      t_exp(s)   mlim   t_start-tGRB(s)  Coadd?
--------------------------------------------------------------------
01:02:31.5   01:02:36.5         5     15.8           84.6       N
01:04:48.1   01:09:27.0       278     17.8          221.2       Y


GRB_name: GRB090904B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9881
SUBJECT: GRB 090904B: Swift detection of a burst
DATE:    09/09/04 01:50:16 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

V. D'Elia (ASDC), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU),
J. R. Cummings (NASA/UMBC), S. T. Holland (CRESST/USRA/GSFC),
J. A. Kennea (PSU), C. B. Markwardt (CRESST/GSFC/UMD),
F. E. Marshall (NASA/GSFC), C. Pagani (PSU), M. Perri (ASDC),
M. H. Siegel (PSU), M. Stamatikos (OSU/NASA/GSFC), M. A. Stark (PSU)
and T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:

At 01:24:18 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090904B (trigger=361831).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 264.191, -25.212 which is 
   RA(J2000)  =  17h 36m 46s
   Dec(J2000) = -25d 12' 43"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows multiple overlapping peaks
starting at T-5 sec with a duration of about 60 sec.  The peak count rate
was ~1800 counts/sec (15-350 keV), at ~3 sec after the trigger. 

The XRT began observing the field at 01:26:32.3 UT, 134.2 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 264.1854, -25.2138
which is equivalent to:
   RA(J2000)  = 17h 36m 44.50s
   Dec(J2000) = -25d 12' 49.7"
with an uncertainty of 2.4 arcseconds (radius, 90% containment). This
location is 19 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 (3.28e+21
cm^-2, Kalberla et al. 2005), with an excess column of 4.8
(+5.33/-4.01) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the White
filter  starting 137 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 8'x8'
region for the list of sources generated on-board covers 100% of the
XRT error circle.  Because of the density of catalogued stars,further
analysis is required to report an upper limit for any afterglow in the
region. 

We note that this is a separate burst from the "A" burst.  
But there may be some confusion resulting from overlapping GCN Notices. 

Burst Advocate for this burst is V. D'Elia (delia 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: GRB090904B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9882
SUBJECT: GRB090904B: REM observations
DATE:    09/09/04 03:03:22 GMT
FROM:    Angelo Antonelli at Obs. Astro. di Roma  <a.antonelli@oa-roma.inaf.it>

S. Covino, L.A. Antonelli, P. D'Avanzo, D. Fugazza, S. Campana, G. Chincarini,
V. D'Elia,  F. D'Alessio, F. Fiore, P. Goldoni, C.  Guidorzi, E. Maiorano, L.
Nicastro, E. Palazzi, E. Pian, S. Piranomonte, L. Stella, G. Tagliaferri, G.
Tosti, V. Testa, S.D. Vergani, F. Vitali report on behalf of the REM team:

The REM 60-cm robotic telescope located at ESO-La Silla reacted promptly after
the Swift alert for GRB09094B. Observations began 108 seconds after the GRB time
(40 s after the trigger) with the R and H bands and continued with all the
available filters (VRIJHK). No transient was singled out in the images, although
a not varying 2MASS star with H=11.95 seems to be coincident with the XRT position.
The field is located very close to the Galactic Center (LII = 2.12 deg, BII =
3.64 deg) and is heavily reddened and crowded, requiring further analyses to
evaluate the chance for this positional coincidence.

Further observations are in progress.




-------------------------------------------------
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GRB_name: GRB090902B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9883
SUBJECT: GRB 090902B: WSRT Radio Observation
DATE:    09/09/04 07:17:14 GMT
FROM:    Alexander van der Horst at NASA/MSFC  <Alexander.J.VanDerHorst@nasa.gov>

A.J. van der Horst (NASA/MSFC/ORAU) A.P. Kamble, R.A.M.J. Wijers
(U of Amsterdam) and C. Kouveliotou (NASA/MSFC) report on behalf of
a large collaboration:

"We observed the position of the GRB 090902B afterglow with the
Westerbork Synthesis Radio Telescope at 4.8 GHz at September 3 12.72 UT
to September 4 0.35 UT, i.e. 1.07 - 1.55 days after the burst (GCN 9866).
We detect a radio source at the 4-sigma level with a flux density
of 111 +/- 28 microJy at the position of the optical counterpart
(GCN 9869, GCN 9874).

We would like to thank the WSRT staff for scheduling and obtaining these
observations."


GRB_name: GRB090904A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9884
SUBJECT: GRB 090904A: NOT observations
DATE:    09/09/04 10:50:17 GMT
FROM:    Pall Jakobsson at U of Iceland  <pja@raunvis.hi.is>

D. Malesani (DARK/NBI), P. Jakobsson (U. Iceland), N. Tanvir
(U. Leicester) and I. Ilyin (AIP) report on behalf of a larger
collaboration:

We observed the field of GRB 090904A (Perri et al., GCN 9879)
with the Nordic Optical Telescope equipped with StanCam.
Observations were carried out on 2009 Sept 4.17 (3.1 hr after
the GRB) in the R- and I-bands. No objects are detected inside
the XRT error circle to a limit of R > 23. However, just outside
the error circle at

RA(J2000)  =  06:43:32.33
Dec(J2000) = +50:12:12.4

there is an object with R = 22 +/- 0.2 mag (calibrated against
several nearby USNO-B1 stars). If weather permits, further
observations are planned tonight to estimate whether the object
is fading.


GRB_name: GRB090904A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9885
SUBJECT: GRB 090904A: Enhanced Swift-XRT position
DATE:    09/09/04 12:16:03 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 1030 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 090904A, 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 = 100.88052, +50.20366 which is equivalent
to:

RA (J2000): 06h 43m 31.33s
Dec (J2000): +50d 12' 13.2"

with an uncertainty of 2.0 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, MNRAS, 397, 1177).

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


GRB_name: GRB090904A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9886
SUBJECT: GRB090904A: Correction to enhanced XRT position
DATE:    09/09/04 12:32:00 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 automatic enhanced XRT position (GCN 9885) was incorrect and should 
be disregarded. The position was obtained by averaging all the PC data 
from the first orbit, however the degree of pile up in this period 
changes by much more than is normal (see the  light curve at: 
http://www.swift.ac.uk/xrt_curves/00361830/). As a result, the PSF of 
the image did not match any of our calibrated PSFs. We apologise for any 
confusion.

The best XRT position available is the enhanced SPER position, which was 
distributed as an XRT Position Update GCN notice about at 01:27 UT. This 
position is RA, Dec = 100.8858, 50.2038, which corresponds to

RA(J2000) =  06h 43m 32.59s
Dec (J2000) = +50d 12' 13.6"

with an uncertainty of 2.3 arcsec (radius, 90% confidence).

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


GRB_name: GRB090904B
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9887
SUBJECT: GRB 090904B: Enhanced Swift-XRT position
DATE:    09/09/04 12:55:48 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 1190 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 090904B, 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 = 264.18534, -25.21305 which is equivalent
to:

RA (J2000): 17h 36m 44.48s
Dec (J2000): -25d 12' 47.0"

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, MNRAS, 397, 1177).

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


GRB_name: GRB090904A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9888
SUBJECT: GRB 090904A: Swift-BAT refined analysis
DATE:    09/09/04 13:16:39 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. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), 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-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090904A (trigger #361830)
(Perri, et al., GCN Circ. 9879).  The BAT ground-calculated position is
RA, Dec = 100.855, 50.235 deg, which is 
   RA(J2000)  =  06h 43m 25.2s 
   Dec(J2000) = +50d 14' 06.9" 
with an uncertainty of 3.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 75%.
 
The mask-weighted light curve shows low level emission starting at ~T-40 sec,
with a small peak at ~T+5 sec. Then there was a larger peak at ~T+50 sec,
and then the largest peak (FRED-like) starting at ~T+123 sec, peaking at
~T+128 sec.  Riding on that tail is a peak ~T+173.  The event is over
in the BAT energy band at ~T+240 sec.  T90 (15-350 keV) is 122 +- 10 sec
(estimated error including systematics).
 
The time-averaged spectrum from T+29.3 to T+186.3 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.01 +- 0.10.  The fluence in the 15-150 keV band is 3.0 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+127.07 sec in the 15-150 keV band
is 1.9 +- 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/361830/BA/


GRB_name: GRB090902B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9889
SUBJECT: GRB 090902B: VLA radio detection
DATE:    09/09/04 13:23:07 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 (VLA) to observe the field of view towards
the GRB 090902B (GCN 9866) at a frequency of 8.46 GHz on 2009 Sep.
03.94 UT. We clearly detect the GRB afterglow at the GROND NIR afterglow
position (GCN 9874) at a flux density of 141+/-39 uJy.

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: GRB090904B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9890
SUBJECT: GRB 090904B: Swift-BAT refined analysis
DATE:    09/09/04 13:27:29 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), V. D'Elia (ASDC), E. E. Fenimore (LANL),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD),
D. M. Palmer (LANL), 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+303 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090904B (trigger #361831)
(D'Elia, et al., GCN Circ. 9881).  The BAT ground-calculated position is
RA, Dec = 264.194, -25.219 deg, which is 
   RA(J2000)  =  17h 36m 46.5s 
   Dec(J2000) = -25d 13' 09.0" 
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 8%.
 
The mask-weighted light curve shows the burst starting at ~T-30 sec, with
several overlapping peaks between T-5 to T+20 sec and another series
from T+30 to T+50 sec. The burst is over by ~T+70 sec  T90 (15-350 keV)
is 47.0 +- 1.7 sec (estimated error including systematics).
 
The time-averaged spectrum from T-2.5 to T+49.7 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.59 +- 0.07.  The fluence in the 15-150 keV band is 1.1 +- 0.0 x 10^-5 erg/cm2.
The 1-sec peak photon flux measured from T+12.42 sec in the 15-150 keV band
is 5.3 +- 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/361831/BA/


GRB_name: GRB090904A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9891
SUBJECT: GRB 090904A: Enhanced Swift XRT position
DATE:    09/09/04 14:28:45 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.

With 6 ks of XRT data, and 5 UVOT images from recent data downlinks we 
have generated an enhanced XRT position for GRB 090904A, which does not
include the problematic first image and is thus reliable.

The enhanced position is RA, Dec = 100.88480, +50.20300 which is
equivalent to:

RA (J2000): 06h 43m 32.35s
Dec (J2000): +50d 12' 10.8"

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, MNRAS, 397, 1177).

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

[GCN OPS NOTE(04sep09):  Per operator's desire, the Subject-line
was changed from "090404A" to "090904A". F.Marshall noticed this.]


GRB_name: GRB090904B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9892
SUBJECT: GRB 090904B: MOA-II Optical observation
DATE:    09/09/04 15:29:08 GMT
FROM:    Kenta Nishimoto at Nagoya U/MOA-II  <nishimo@stelab.nagoya-u.ac.jp>

K. Nishimoto, T. Sako, and D. Suzuki (STE Lab, Nagoya Univ.)
on behalf of the MOA Collaboration  report:

We searched for an optical afterglow of GRB090904B (GCN9881, V. D'Elia
et al.) starting from 07:34:56.9 UT on 2009 Sep 4 (6 hours after the
burst) with the MOA-II 1.8m telescope at Mt.John observatory in New Zealand.
In a single image of a 60 sec 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 9887),
except a USNO-B1.0 catalog star, 0647-0516939, which has I mag=15.10 and
the separation of 1.8 arcsec from the center of the position.

Quick estimation of the limiting magnitude is >20.5 calibrated by using
USNO-B1.0 catalog. 


GRB_name: GRB090904B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9893
SUBJECT: GRB 090904B: Swift XRT Refined Analysis
DATE:    09/09/04 16:49:07 GMT
FROM:    Valerio D'Elia at INAF-OAR  <delia@mporzio.astro.it>

V. D'Elia, G. Stratta, M. Perri (ASDC) report on behalf of
the Swift-XRT team:

We have analysed 6.2 ks of XRT data for GRB 090904B (D'Elia et al. GCN
Circ. 9881), from 159 s to 37.1 ks after the BAT trigger. The data are
entirely in Photon Counting (PC) mode. The enhanced XRT position for
this burst was given by Osborne et al. (GCN. Circ 9987).

The light curve, after an initial rise, peaks at T+260 s, while the 
following
decay can be modelled with a power-law with a decay
index of alpha=1.20+-0.05 (90% confidence level).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.67 (+0.26, -0.24, 90%
confidence level). The best-fitting absorption column is 6.3
(+2.5, -1.1) x 1021 cm-2, in excess with respect to the Galactic value of
3.3 x 1021 cm-2 (Kalberla et al. 2005). The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum is 6.8 x 10-11 (1.1 x 10-10) 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 0.0040 count s-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.7 x
10-13 (4.4 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/00361831.

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


GRB_name: GRB090904A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9894
SUBJECT: GRB 090904A: Swift-XRT refined analysis
DATE:    09/09/04 16:56:03 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 12 ks of XRT data for GRB 090904A (Perri et
al.,
GCN Circ. 9879), from 134 s to 29.6 ks after the BAT trigger. The enhanced
XRT position for this burst was given by Evans (GCN. Circ. 9891).

During the first Swift orbit, the light-curve shows a steep decay
with a large superimposed flare peaking at about T+300 s. Starting
from T+1000 s, the curve is well described by a broken power-law model
with temporal decay indices alpha1=0.2+/-0.1, alpha2=0.9+/-0.3 and a
temporal break at around T+12 ks.

A spectrum extracted from the PC mode data from T+460 s to T+29.6 ks can
be fitted with an absorbed power-law model with a photon spectral index of
2.46 (+0.16,-0.26) and an absorption column density of
1.03 (+0.66,-0.64)e21 cm-2 in excess of the Galactic value of
9.3e20 cm-2 (Kalberla et al. 2005). The counts-to-observed (-unabsorbed)
0.3-10 keV flux conversion factor deduced from this spectrum is
3.3e-11 (6.2e-11) erg cm-2 count-1. Errors are given at the
90% confidence level.

If the light curve continues to decay with a power-law index of
0.9, the count rate at T+24 hours will be 6e-3 count s-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of
2.0e-13 (3.7e-13) erg cm-2 s-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00361830.

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


GRB_name: GRB090904B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9895
SUBJECT: GRB 090904B: Fermi GBM detection
DATE:    09/09/04 22:01:47 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 01:24:13.93 UT on 04 September 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090904B (trigger 273720255 / 090904058), 
which was also detected by the SWIFT-BAT (D'Elia et al. 2009, GCN 9881).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 113 degrees.

The GBM light curve consists of three bright peaks
with a duration (T90) of about 71 s (8-1000 keV). 
The time-averaged spectrum from T0-9.2 s to T0+65.5 s is 
well fit by a power law function with an exponential
high energy cutoff.  The power law index is 1.41 +/- 0.08 and
the cutoff energy, parameterized as Epeak, is 149.30 +/- 22.10 keV
(chi squared 243.6 for 238 d.o.f.).

The event fluence (8-1000 keV) in this time interval is 
(2.44 +/- 0.15)E-05 erg/cm^2. The 1-sec peak photon flux measured 
starting from T0+21.5 s in the 8-1000 keV band 
is 9.8 +/- 0.7 ph/s/cm^2.

A Band function fits the spectrum equally well 
(chi squared 239.0 for 237 d.o.f.) with Epeak= 106.30 +/- 24.60 keV, 
alpha = -1.26 +/- 0.15 and beta = -2.18 +/- 0.18. 


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


GRB_name: GRB090829A
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9896
SUBJECT: GRB 090829A: Suzaku WAM observation of the prompt emission
DATE:    09/09/05 03:02:48 GMT
FROM:    Kazuhiro Noda at Miyazaki U  <kaz1206@astro.miyazaki-u.ac.jp>

K. Noda, E. Sonoda, N. Ohmori, K. Kono, H. Hayashi,
A. Daikyuji, Y. Nishioka, M. Yamauchi (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 090829A (Fermi-GBM trigger #273254860 / 090829672 ;
Colleen et al., GCN9849)
triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an
energy range of 50 keV - 5 MeV at 2009-08-29 16:08:14.99 UT (=T0).

The observed light curve shows a multi-peaked structure, starting at
T0-40 s and ending at T0+60 s, with a total duration (T90) of about 30 s.
The fluence in 100 - 1000 keV was 5.65(-1.19, +0.34) x10-5 erg/cm2.
The 1-s peak flux measured from T0+12 s was 13.07(-1.00, +0.81)
photons/cm2/s
in the same energy range.

Preliminary result shows that the time-averaged spectrum from
T0-40 s to T0+60s is well fitted by a power-law with exponential cutoff
model:
dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
alpha: 1.52(-0.29, +0.26), and
Epeak: 344(-52, +91) keV (chi2/d.o.f. = 50.7/36).

All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.

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: GRB090902B
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9897
SUBJECT: GRB 090902B: Suzaku WAM observation of the prompt emission
DATE:    09/09/05 04:36:48 GMT
FROM:    Kazutaka Yamaoka at Aoyama Gakuin U  <yamaoka@phys.aoyama.ac.jp>

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

The Fermi detected long GRB 090902B (Bissaldi et al., GCN 9866, 
 de Palma et al. GCN 9867) triggered the Suzaku Wide-band All-sky 
Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 
11:05:08.446 UT (=T0). The observed light curve shows a multi-peaked 
structure lasting from T0-0.5 s to T0+24.5 s with a duration (T90) of about 
19 seconds. The fluence in 100 - 1000 keV was 1.45 (-0.04, +0.03)x10^-4 erg/cm^2. 
The 1-s peak flux measured from T0+14.5 s was 21.3 (-1.3, +0.9) photons/cm^2/s
in the same energy range.

Preliminary result shows that the time-averaged spectrum from
T0-0.5 s to T0+24.5 s is well fitted by a power-law with exponential 
cutoff model:
  dN/dE ~  E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
  alpha:      0.91 +/- 0.10, and
  Epeak:      885 (-38, +39) keV (chi^2/d.o.f. = 25.5/24).

Due to this GRB brightness, a 3% systematcic error was 
 added for low energy channels.  In addition, there might be 
  some calibration uncertainties in fluence because the GRB 
  photons came into the WAM through the base plate of the satellite. 
All the quoted errors are at 90% confidence level. 

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: GRB090904B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9898
SUBJECT: GRB 090904B: Swift/UVOT Refined Analysis
DATE:    09/09/05 05:45:47 GMT
FROM:    Tyler Pritchard at PSU  <tapritchard@astro.psu.edu>

T. A. Pritchard (PSU) and D'Elia (ASDC) report on behalf of the
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 090904B,
138 seconds
after the BAT trigger (D'Elia et al., GCN Circ. 9881). We do not detect
any source
at the UVOT-enhanced XRT position (J.P. Osbourne et al., GCN Circ.9887).

The 3-sigma upper limits for the exposures are:

Filter   T_start(s)   T_stop(s)   Exp(s)  Mag (3-sigma upper limit)
-------------------------------------------------------------
white      138          1357       369      > 22.17
v          625          1237        78      > 19.08
b          551           1335        78      > 20.08
u          295            545       246      > 20.41
-------------------------------------------------------------

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


GRB_name: GRB090904A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9899
SUBJECT: GRB 090904A: Swift/UVOT Refined Analysis
DATE:    09/09/05 05:46:33 GMT
FROM:    Tyler Pritchard at PSU  <tapritchard@astro.psu.edu>

T. A. Pritchard (PSU), C. A. Swenson (PSU) and M. Perri (ASDC) report on 
behalf of the
Swift/UVOT team:

The Swift/UVOT began settled observations of GRB 090904A,  141 seconds 
after the
BAT trigger (M. Perri et al., GCN Circ. 9879). We do not detect any 
source at the
UVOT-enhanced XRT position (M.R. Goad, GCN Circ. 9885).

The 3-sigma upper limits for the exposures are:

Filter   T_start(s)   T_stop(s)   Exp(s)  Mag (3-sigma upper limit)
-------------------------------------------------------------
white      141       1189       341      > 21.57
v          629        1078        58      > 18.72
b          555          1177        58      > 19.59
u          299        1152       285      > 20.43
uvw1    679  1127     58      > 19.11
uvm2    827  847     19      > 17.61
uvw2    605  1054     58      > 19.17
-------------------------------------------------------------

The quoted upper limits have not been corrected for the expected
Galactic extinction corresponding to a reddeningalong the line of sight of
E_(B-V) = 0.1 mag (Schlegel et al., 1998, ApJS, 500, 525).  All 
photometry is on the
UVOT photometric system described in Poole et  al. (2008, MNRAS, 383, 627).


GRB_name: GRB090831A
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9900
SUBJECT: GRB 090831A: Suzaku WAM observation of the prompt emission
DATE:    09/09/05 07:59:58 GMT
FROM:    Norisuke Ohmori at Miyazaki U  <ohmori@astro.miyazaki-u.ac.jp>

N. Ohmori, K. Noda, E. Sonoda, K. Kono, H. Hayashi, 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 090831A (Fermi-GBM trigger 273396998 / 090831317;
Arne et al., GCN 9850, MAXI-GSC; Matsuoka et al., GCN 9852) 
triggered the Suzaku Wide-band All-sky 
Monitor (WAM) which covers an energy range of 50 keV - 5 MeV
at 07:36:36.472 UT (=T0).

The observed light curve shows main three peaks starting at T0s, 
ending at T0+10s, followed by a long weak tail seen up to T0+48s.
The total T90 duration is about 53 seconds.

The fluence in 100 - 1000 keV was 6.8 (-1.8, +1.0)x10-6 erg/cm2.
The 1-s peak flux measured from T0+4 s was 1.8 (-0.2, +0.3) photons/cm2/s 
in the same energy range.

Preliminary result shows that the time-averaged spectrum from
T0 s to T0+48 s is well fitted by a power-law with exponential cutoff model:
  dN/dE ~  E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
  alpha        0.89(-0.91, +0.65), and
  Epeak        286(-57, +88) keV (chi2/d.o.f. = 93/80).
 
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: GRB090904B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9901
SUBJECT: GRB 090904B: GROND detection of the optical afterglow
DATE:    09/09/07 12:54:08 GMT
FROM:    Thomas Kruehler at MPE/MPI  <kruehler@mpe.mpg.de>

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

The field of GRB 090904B (Swift trigger 361831, D'Elia et al., GCN #9881, 
also GBM trigger 273720255/090904058, Goldstein, GCN #9895) was observed 
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 01:28 UT, on September 4, 2009, 4 minutes 
after the GRB trigger. The field was observed during a second epoch, 
starting at 01:28 UT, on September 5, 2009, 24.07 hours after the GRB 
trigger. Image subtraction between the two epochs reveals a fading source 
on the edge of the enhanced Swift/XRT error circle (Osborne et al., GCN 
#9887). The position of the afterglow is

RA (J2000) = 17h 36m 44.59s
DEC (J2000) = -25d 12' 46.5"

with an uncertainty of 0.5" in each coordinate.

The afterglow is located roughly 1.1" South/East of the 2MASS/USNO star 
reported by REM (Covino et al., GCN #9882) and MOA-II (Nishimoto et al., 
GCN #9892), and both sources are strongly blended in the GROND images of 
1.0" seeing.

At a midtime of 6.5 minutes after the burst, we measure rough preliminary 
AB magnitudes of the optical afterglow of r' ~ 22.2, i ~ 20.6 and z' ~ 19.7.

Calibrations were done against GROND zero points, and given magnitudes are 
not corrected for the significant Galactic extinction corresponding to a 
reddening of E(B-V) = 1.76 mag (Schlegel et al. 1998). The object is 
detected in all bands except g', which, given the large Galactic foreground 
extinction, does not constrain the redshift.


GRB_name: GRB090823A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9902
SUBJECT: GRB 090823: Swift XRT confirmation of the X-ray afterglow 
DATE:    09/09/08 17:33:53 GMT
FROM:    Dirk Grupe at PSU/Swift-XRT  <grupe@astro.psu.edu>

D. Grupe (PSU)  reports on behalf  of the Swift XRT team:

Swift has observed the field of IPN burst GRB090823 (Cummings et
al. GCN Circ. 9835) twice after the initial 4.7 ks observation
on 2009-08-24 (Grupe et al., GCN Circ. 9840) for 9.5 ks on
2009-08-27 and 7.5 ks on 2009-09-05. During the 2009-08-27
observation the X-ray source was clearly detected again at a level
of (2.3+/-0.6)e-3 counts s-1 (about 1.1e-13 ergs s-1 cm-2), roughly
half of the flux during the first observation. During the
2009-09-05 observation however, the X-ray source is definitely
gone and we can only derive a 3-sigma upper limit at a level of
1.9e-3 counts s-1 (9.4e-14 ergs s-1 cm-2). We can confirm that the
source listed in GCN circ. 9840 is the X-ray afterglow of
GRB 090823.


GRB_name: GRB090814A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9903
SUBJECT: GRB 090814A: Skynet/DSO & GORT Observations
DATE:    09/09/09 00:41:59 GMT
FROM:    Josh Haislip at U.North Carolina  <haislip@physics.unc.edu>

J. Haislip, D. Reichart, K. Ivarsen, A. Smith, D. Caton, L. Hawkins, L. 
Cominsky, K. McLin, T. Graves, G. Spear, A. LaCluyze, A. Foster, J. Moore, 
A. Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. Nysewander 
report:

Skynet observed the Swift/BAT localization of GRB 090814A (Ukwatta et al., 
GCN 9793) with the 14" Dark Sky Observatory telescope in North Carolina 
beginning 71.1 minutes after the trigger in RI through variable cloud 
cover.

Skynet continued observing with the 14" GORT telescope at Hume Observatory 
in California beginning 3.3 hours after the the trigger in RI.

We do not detect the afterglow (Updike et al., GCN 9794).  Stacking only 
images that increase the limiting magnitude yields:

mean
time                                    3-sigma    secondary
since                                   limiting   calibration
trigger  telescope  exposures   filter  magnitude  stars *

75.4 m   DSO-14     2 x 160 s   I       18.5       13 SDSS 6
                     + 1 x 80 s
86.4 m   DSO-14     4 x 160 s   R       19.2       9 SDSS 6
96.6 m   DSO-14     3 x 160 s   I       17.8       13 SDSS 6
105.3 m  DSO-14     1 x 160 s   R       16.9       9 SDSS 6
4.7 h    GORT       35 x 80 s   I       20.1       8 SDSS 6
5.2 h    GORT       40 x 80 s   R       20.8       7 SDSS 6
24.9 h   DSO-14     11 x 160 s  R       20.0       9 SDSS 6

* Transformed using Jester et al., 2005, ApJ, 130, 873.


GRB_name: GRB090910A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9904
SUBJECT: GRB 090910: Fermi GBM detection
DATE:    09/09/11 19:32:46 GMT
FROM:    Vandiver Chaplin at UAH/Fermi-GBM  <chapliv@email.uah.edu>

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

"At 19:29:48.81 UT on 10 SEP 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090910 (trigger 274303790 / 090910812).

The on-ground calculated location, using the GBM trigger
data, is RA = 296.2, DEC = 72.3 (J2000 degrees,
equivalent to 19h 44m, 72 d 18'), with an uncertainty
of 1.0 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 107 degrees.

The on-board GBM Flight Software localization for this event,
as reported in the GCN notice, was consistent with a position
near the Earth's limb.  Furthermore, the trigger occurred as
the spacecraft was at a high magnetic latitude.  The resulting
autonomous classification for the event was "Distant Particles",
which is erroneous.

The GBM light curve consists of three distinct pulses
close in time from T0-5s to about T0+45s, with a smaller pulse
visible in several detectors at about T0+70s.  The duration (T90)
of this event is approximately 62s (8-1000 keV).
The time-averaged spectrum from T0-7.2 s to T0+44 s is
best fit by a Band function with Epeak = 274.8 +/- 56.1 keV,
alpha = -0.9 +/- 0.1, and beta = -2.0 +/- 0.2 (chi squared 397.41
for 360 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(9.2 +/- 0.7)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+2 s in the 8-1000 keV band
is 2.3 +/- 0.6 ph/s/cm^2.

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


GRB_name: GRB090912A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9905
SUBJECT: GRB 090912: Swift detection of a burst
DATE:    09/09/12 16:15:11 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

T. N. Ukwatta (GSFC/GWU), S. D. Barthelmy (GSFC), M. M. Chester (PSU),
S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),
V. Mangano (INAF-IASFPA), K. L. Page (U Leicester),
P. Romano (INAF-IASFPA), T. Sakamoto (NASA/UMBC),
B. Sbarufatti (INAF-IASFPA), R. L. C. Starling (U Leicester) and
E. Troja (NASA/GSFC/ORAU) report on behalf of the Swift Team:

At 15:50:29 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090912 (trigger=362633).  Swift executed a delayed slewed
to the burst. 
The BAT on-board calculated location is 
RA, Dec 188.092, +61.513, which is 
   RA(J2000)  =  12h 32m 22s
   Dec(J2000) = +61d 30' 45"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows two peaks at T+0 and
at T+90 with a total duration of about 130 sec.  The peak count rate
was ~1000 counts/sec (15-350 keV), at ~5 sec after the trigger. 

The XRT began observing the field at 16:03:42.4 UT, 792.6 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 188.0422, 61.4843 which
is equivalent to:
   RA(J2000)  = 12h 32m 10.13s
   Dec(J2000) = +61d 29' 03.5"
with an uncertainty of 2.2 arcseconds (radius, 90% containment). This
location is 134 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 (1.28e+20
cm^-2, Kalberla et al. 2005), with an excess column of 6.2
(+4.43/-3.60) x 10^21 cm^-2 (90% confidence). 


UVOT took a finding chart exposure of 150 seconds with the White filter
starting 795 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 0.01. 




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: GRB090912A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9906
SUBJECT: GRB 090912: Enhanced Swift-XRT position
DATE:    09/09/12 19:00:06 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 1374 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 090912, 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 = 188.04297, +61.48454 which is equivalent
to:

RA (J2000): 12h 32m 10.31s
Dec (J2000): +61d 29' 04.4"

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, MNRAS, 397, 1177).

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


GRB_name: GRB090912A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9907
SUBJECT: GRB 090912 optical upper limit
DATE:    09/09/13 10:17:51 GMT
FROM:    AAVSO GRB Network at AAVSO  <matthewt@aavso.org>

Arto Oksanen (Hankasalmi Obs., Hankasalmi, Finland) reports to the AAVSO 
International High Energy Network the following optical observations of 
the field of GRB090912 (GCN Circ. #9905, Ukwatta et al.):

A. Oksanen reports an upper limit on the optical afterglow of CR=21.6, 
measured relative to USNO-A2.0 1500-05568008 (R=15.7).  The X-ray 
afterglow position (Beardmore et al., GCN #9906) was observed using the 
0.4-m Hankasalmi Observatory RC telescope with an SBIG STL-1001E CCD 
camera and clear filter.  A total of 57 one-minute exposures were 
obtained, with the mid-point of the exposures at 2009 Sept 12 19:33 UT, 
approximately 3.7 hours post-burst.  Two faint stars near the burst 
location are present in DSS2 images, but there is no transient source at 
the burst location to a limit of CR=21.6.

A detailed report of these observations may be found at the following URL:
ftp://ftp.aavso.org/grb/ArtoOksanen_GRB090912_2455087.38910_.txt

A fits image is also available at
ftp://ftp.aavso.org/grb/ArtoOksanen_GRB090912_2455087.38910_.fits

The AAVSO thanks the Curry Foundation for its support of the
AAVSO International High Energy Network.


GRB_name: GRB090912A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9908
SUBJECT: GRB 090912: Swift/UVOT Upper Limits
DATE:    09/09/13 12:54:57 GMT
FROM:    Peter Curran at MSSL  <pac@mssl.ucl.ac.uk>

P.A. Curran (MSSL-UCL) and T. N. Ukwatta (GSFC/GWU) report on behalf of 
the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 090912 796s after 
the BAT trigger (Ukwatta et al., GCN 9905). No optical afterglow consistent 
with the enhanched Swift XRT position (Beardmore et al., GCN 9906)  is detected 
in the 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) and subsequent exposures are:


Filter         T_start(s)   T_stop(s)     Exp(s)      Mag

white          796          946           147         >20.50 (FC)
white          796          7707          608         >21.09
v              1129         8118          294         >19.04
b              1228         7502          254         >19.91
u              1204         7297          313         >19.58
w1             1179         7092          313         >19.82
m2             6688         8273          344         >19.78
w2             7713         7913          197         >19.78

The values quoted above are not corrected for the Galactic extinction due to 
the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 
1998).


GRB_name: GRB090912A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9909
SUBJECT: GRB 090912, Swift-BAT refined analysis
DATE:    09/09/13 18:49:52 GMT
FROM:    Tilan Ukwatta at GSFC/GWU  <tilan.ukwatta@gmail.com>

T. N. Ukwatta (GSFC/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), 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-240 to T+962 sec from the recent
telemetry downlink,we report further analysis of BAT
GRB 090912 (trigger #362633) (Ukwatta, et al.,
GCN Circ. 9905). The BAT ground-calculated position is
RA, Dec = 188.046, 61.475 deg which is
   RA(J2000)  =  12h 32m 11.1s
   Dec(J2000) = +61d 28' 29.4"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90%
containment). The partial coding was 30%.

The mask-weighted light curve shows two peaks. The first
start around T-4 sec, shows three sub peaks at ~T+0 sec,
~T+4 sec, and ~T+7 sec, and ends around T+25 sec. The
second peak starts at ~T+70 sec, peaks at ~T+88, and ends
around T+145 sec. T90 (15-350 keV) is 144.0 +- 22.6 sec
(estimated error including systematics).

The time-averaged spectrum from T-15.9 to T+160.1 sec is
best fit by a power law with an exponential cutoff.
This fit gives a photon index 0.91 +- 0.44, and Epeak
of 69.3 +- 19.5 keV (chi squared 42.50 for 56 d.o.f.).
For this model the total fluence in the 15-150 keV band
is 4.5 +- 0.3 x 10^-6 erg/cm2 and the 1-sec peak flux
measured from T+87.56 sec in the 15-150 keV band is
1.0 +- 0.1 ph/cm2/sec.  A fit to a simple power law
gives a photon index of 1.66 +- 0.09
(chi squared 52.84 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/362633/BA/


GRB_name: GRB090912A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9910
SUBJECT: GRB 090912: Swift-XRT refined analysis
DATE:    09/09/13 20:38:38 GMT
FROM:    Boris Sbarufatti at INAF-IASF-Pa  <sbarufatti@ifc.inaf.it>

Sbarufatti B., Mangano V. (INAF-IASFPA) and T. Ukwatta (GSFC/GWU)
report on behalf of the Swift Team:

We have analyzed the first 22.5 ks of of Swift-XRT data of
GRB 090912 (trigger 362633; Ukwatta, et al., GCN Circ. 9905).
The data are entirely in Photon Counting (PC) mode, from T+806 s to
T+66 ks. The enhanced XRT position for this burst was given by
Beardmore et al. (GCN. Circ 9906).

The 0.3-10 keV X-ray light curve is best fitted by a power-law
with decay index -0.75+/-0.03. Faint flaring activity is
detected along the decay. If decaying at the present rate, the
predicted rate for T+ 48h is 1.0e-2 counts/s.

The average spectrum is best fit by a power-law with index
2.1+/-0.1. The absorbing column is NH = (5.2+/-0.7)E20 cm^-2,
in excess with respect to the Galactic value of 1.3E20 cm^-2
(Kalberla et al. 2005). The average observed (unabsorbed) fluxes are
3.0(5.7)E-12 ergs cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00362633 .

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


GRB_name: GRB090827A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9911
SUBJECT: GRB 090827: Confirmation of the X-ray afterglow 
DATE:    09/09/14 13:16:35 GMT
FROM:    Kim Page at U.of Leicester  <kpa@star.le.ac.uk>

P.A. Evans, K.L. Page (U. Leicester) and S.R. Oates (MSSL-UCL) report on 
behalf of the Swift-XRT team:

Swift reobserved the field of GRB 090827 (Cummings et al. GCN Circ. 9846) 
on 2009 September 9th and 13th, 13 and 17 days after the trigger, 
respectively. The XRT gathered 14 ks of Photon Counting mode data in this 
time.

The source reported by Evans & Oates (GCN Circ. 9847) is not detected,
with a 3-sigma upper limit of 8.6 x 10^-4 count s^-1, significantly below
the level of the previous detection. We thus conclude that this source
was the afterglow of GRB 090827.

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


GRB_name: GRB090915A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9912
SUBJECT: GRB 090915 Swift-BAT detection of a burst in ground analysis
DATE:    09/09/16 03:11:44 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <james.r.cummings@nasa.gov>

J. R. Cummings (NASA/GSFC/CRESST) and
C. B. Markwardt (NASA/GSFC/CRESST)
on behalf of the Swift-BAT team

At 15:35:36 Swift-BAT triggered on GRB 090915. This was
probably the same event as Fermi-GBM trigger 274721737. No
source was found onboard. A weak but significant source was
found in ground analysis, 15 degrees from the GBM ground-
calculated (2nd version) position as reported at
http://gcn.gsfc.nasa.gov/fermi_grbs.html. The GBM position
was also in the BAT FOV.

The BAT ground-calculated position is
RA, Dec = 237.990, +15.480 deg which is
    RA(J2000)  =  15h 51m 57.6s
    Dec(J2000) = +15d 28' 48"
with an uncertainty of 3 arcmin, (radius, sys+stat, 90%
containment). The partial coding was 12%.

The mask-weighted light curve shows a single weak peak.
T90 (15-350 keV) is 8 +- 2 sec
(estimated error including systematics).

The time-averaged spectrum from T-3 to T+5 sec is best fit
by a power law. This fit gives a photon index 1.0 +- 0.2.
For this model the total fluence in the 15-150 keV band
is 5 +- 2 x 10-7 erg/cm2 and the 1-sec peak flux measured
from T+2 sec in the 15-150 keV band is 0.8 +- 0.3 ph/cm2/sec.
All the quoted errors are at the 90% confidence level.

A Swift TOO has been requested and approved. The narrow-
field instruments will observe the location approximately
13 hours after the burst.


GRB_name: GRB090916A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9913
SUBJECT: GRB 090916: Swift detection of a short burst
DATE:    09/09/16 07:30:36 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

E. Troja (NASA/GSFC/ORAU), A. P. Beardmore (U Leicester),
E. A. Hoversten (PSU), H. A. Krimm (CRESST/GSFC/USRA),
C. B. Markwardt (CRESST/GSFC/UMD), P. T. O'Brien (U Leicester),
K. L. Page (U Leicester), D. M. Palmer (LANL),
P. Romano (INAF-IASFPA), A. Rowlinson (U Leicester) and
M. H. Siegel (PSU) report on behalf of the Swift Team:

At 07:00:44 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090916 (trigger=362818).  Swift did not slew to the GRB
due to a Moon constraint.  The BAT on-board calculated location is 
RA, Dec 126.579, +25.933 which is 
   RA(J2000) = 08h 26m 19s
   Dec(J2000) = +25d 55' 60"
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 ~0.4 sec, followed
by ~8 seconds of low-energy emission.  The peak count rate
was ~2500 counts/sec (15-350 keV), at ~0 sec after the trigger. 

Due to an observing constraint, Swift cannot immediately slew to
the BAT position.  There will thus be no XRT or UVOT data for this 
trigger until later today. 

Burst Advocate for this burst is E. Troja (eleonora.troja 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: GRB090915A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9914
SUBJECT: GRB 090915: Swift-XRT detection of a fading X-ray counterpart
DATE:    09/09/16 11:19:58 GMT
FROM:    Andy Beardmore at U Leicester  <apb@star.le.ac.uk>

A. P. Beardmore, K. L. Page (U. Leicester) and T. Sakamoto (NASA/UMBC)
report on behalf of the Swift-XRT team :

The Swift-XRT started observing the field of GRB 090915 (Cummings and
Markwardt, GCN Circ. 9912) at 2009-09-16 03:59 UT, 12.4 hours after
the trigger. In 5ks of photon counting mode data, spanning two orbits,
we detect a source which fades from 0.0099 +/- 0.0022 count/s to
0.0033 +/- 0.0016 over a interval of 5.9ks.

Using 1678 s of XRT Photon Counting mode data and 1 UVOT image, 
we find an astrometrically corrected X-ray position (using the
XRT-UVOT alignment and matching UVOT field sources to the USNO-B1
catalogue) for the source of RA, Dec (J2000) = 238.02021, 15.48775
which is equivalent to :

RA  (J2000):  15 52 4.85
Dec (J2000): +15 29 15.9

with an uncertainty of 3.3 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, MNRAS, 397, 1177).

The spectrum of the data from 44.6 ks to 52.8 ks after the trigger can
be fit by an absorbed powerlaw with a photon index of 1.20 +0.97/-0.54 
and a column density upper limit of 1.4 x 10^21 cm^-2, consistent with
the Galactic value of 3.2 x 10^20 cm^-2 in the direction of the
burst. The observed 0.3-10 keV flux for this spectrum is 4.9 +3.3/-4.9
x 10^-13 erg cm^-2 s^-1 which corresponds to an unabsorbed 0.3-10 keV
flux of 5.1 x 10^-13 erg cm^-2 s^-1.

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


GRB_name: GRB090916A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9915
SUBJECT: GRB 090916, Swift-BAT refined analysis 
DATE:    09/09/16 12:54:14 GMT
FROM:    Hans Krimm at NASA-GSFC  <hans.a.krimm@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),
E. Troja (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):

Using the data set from T-239 to T+963 sec from the recent telemetry 
downlink,
we report further analysis of the short BAT GRB 090916 (trigger #362818)
(Troja, et al., GCN Circ. 9913).  The BAT ground-calculated position is
RA, Dec = 126.582, 25.941 deg which is
  RA(J2000)  =  08h 26m 19.6s
  Dec(J2000) = +25d 56' 27.3"
with an uncertainty of 2.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 34%.

The mask-weighted light curve consisted of a single peak of 0.32 sec 
duration
starting at T-0.128 sec, followed by low-level emission extending out to 
about
T+70 sec. T90 (15-350 keV) is 63.4 +- 15.2 sec (estimated error including
systematics).

The time-averaged spectrum from T-0.0 to T+68.5 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.42 +- 0.33.  The total fluence in the 15-150 keV band is
9.5 +- 1.8 x 10-7 erg/cm2. The peak second starting from T-0.036 sec is
best fit by a simple power-law model. The power law index of the peak-second
spectrum is 1.41 +- 0.28.  The 1-sec peak fluence in the 15-150 keV band is
1.5 +- 0.26 x 10-7 erg/cm2. The 1-sec peak photon flux in the
15-150 keV band is 1.9 +- 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/362818/BA/


GRB_name: GRB090902B
Detection_method: Fermi LAT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9916
SUBJECT: GRB 090902B: Skynet/PROMPT Observations
DATE:    09/09/16 20:05:51 GMT
FROM:    Josh Haislip at U.North Carolina  <haislip@physics.unc.edu>

J. Haislip, D. Reichart, K. Ivarsen, A. LaCluyze, A. Foster, J. Moore, A. 
Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. Nysewander 
report:

Skynet observed the Fermi/LAT localization of GRB 090902B (de Palma et al., 
GCN 9867) with four of the 16" PROMPT telescopes at CTIO beginning 13.3 
hours after the trigger in BVRI through variable cloud cover.

We do not detect the afterglow (Kennea et al., GCN 9868; Swenson & Siegel, 
GCN 9869).  Stacking only images that increase the limiting magnitude 
yields:

mean                                                       1-sig.   1-sig.
time                                3-sig.                 sys.     stat.
since                               lim.     cal.          cal.     cal.
trig.   tel.       exp.      fil.   mag.     stars         unc.     unc.
(h)                (# x s)                                 (mag)    (mag)

14.4    PROMPT-4   18 x 80   R      19.8     240 USNO B1   0.185    0.001
14.4    PROMPT-3   18 x 80   B      19.0     100 USNO B1   0.296    0.002
14.4    PROMPT-5   18 x 80   I      19.0     278 USNO B1   0.234    0.001
14.4    PROMPT-2   17 x 80   V      19.0     217 NOMAD     0.255    0.001


GRB_name: GRB090702A
Detection_method: IBAS
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9917
SUBJECT: GRB 090702: Skynet/GORT Observations
DATE:    09/09/16 20:08:45 GMT
FROM:    Josh Haislip at U.North Carolina  <haislip@physics.unc.edu>

J. Haislip, D. Reichart, L. Cominsky, K. McLin, T. Graves, G. Spear, K. 
Ivarsen, M. Schubel, A. LaCluyze, A. Foster, J. Moore, A. Oza, J. Styblova, 
A. Trotter, J. A. Crain, and M. Nysewander report:

Skynet observed the INTEGRAL/IBAS localization of GRB 090702 (Paizis et 
al., GCN 9603) with the 14" GORT telescope at Hume Observatory in 
California beginning 18.2 hours after the the trigger in I.

We do not detect the afterglow (Sbarufatti & Mangano, GCN 9607).  Stacking 
only images that increase the limiting magnitude yields:

mean                                                 1-sig.   1-sig.
time                            3-sig.               sys.     stat.
since                           lim.     cal.        cal.     cal.
trig.   tel.   exp.      fil.   mag.     stars*      unc.     unc.
(h)            (# x s)                               (mag)    (mag)

18.2    GORT   2 x 80    I      17.7     32 SDSS 7   0.051    0.007

* Transformed using Jester et al., 2005, ApJ, 130, 873.


GRB_name: GRB090915A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9918
SUBJECT: GRB 090915: Swift/UVOT detection of an optical afterglow candidate
DATE:    09/09/16 22:01:24 GMT
FROM:    Erik Hoversten at Swift/Penn State  <hoversten@astro.psu.edu>

E. A. Hoversten (PSU) and T. Sakamoto (NASA/UMBC) report on behalf of  
the
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 090915
44647 s after the BAT trigger (Cummings & Markwardt, GCN Circ. 9912).
A faint source is detected with 5.6-sigma confidence in the summed
UVOT observations at the position RA, Dec (J2000) = 238.02016,15.48772
which is equivalent to:

      RA (J2000) = 15:52:04.84
     Dec (J2000) = 15:29:15.8

with an estimated uncertainty of 0.8 arcsec (radius, 90% confidence).
This position is 0.2 arcsec from the UVOT-enhanced XRT position
(Beardmore, et al. GCN Circ. 9914) and the two positions agree within
the error bars.  It is unclear at this point if the source is fading,
but follow-up Swift observations are being planned.

The observed magnitudes using the UVOT photometric system (Poole et
al. 2008, MNRAS, 383, 627) for the initial exposures are:

Filter   T_start(s)   T_stop(s)   Exp(s)          Mag
=======================================================================
white      45492       52117       1647     22.15 +/- 0.24 (4.7 sigma)
v          46338       52837       1583     21.08 +/- 0.39 (2.8 sigma)
u          44647       51275       1647     21.40 +/- 0.43 (2.5 sigma)


The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.05 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB090912A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9919
SUBJECT: GRB 090912: optical observation
DATE:    09/09/16 22:13:56 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

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

We observed the field of  the Swift GRB 090912 (Ukwatta  et al., GCN 9905) 
with Zeiss-600 telescope of  SAI MSU Crimean branch in  R-filter on Sep.12 
between  (UT) 17:41:36 - 19:08:10.  Within XRT error circle (Beardmore et 
al., GCN  9906) we do not detect any source. However  in a stacked image we 
detect faint source at the coordinates RA(J2000)=  12 32 09.82 Dec(J2000)= 
+61 29 04.54 with uncertainty of 0.5 arcsec. It is 3.5" apart from XRT 
center of the circle of 1.8" radius. We suggest the detected source as 
afterglow candidate and urge  deep observation to confirm variable nature of 
the source.

The photometry of the source against nearby USNO-B1.0 star 1515-0196640 
RA(J2000)= 12:32:18.77 Dec(J2000)= +61:30:00.3 assuming R=19.06 is 
following:

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

0.1086  R     4620     21.8 +/- 0.3 


GRB_name: GRB090915A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9920
SUBJECT: GRB 090915: SARA detection of afterglow candidate
DATE:    09/09/16 22:34:15 GMT
FROM:    Adria C. Updike at Clemson U  <aupdike@clemson.edu>

Adria C. Updike, Dieter H. Hartmann (Clemson University), Brian Murphy
(Butler University), and Kenneth Rumstay (Valdosta State University)
report:

We observed the field of GRB 090915 (Cummings & Markwardt GCN 9912,
Fermi-GBM trigger 274721737) using the 0.9m SARA telescope located at Kitt
Peak National Observatory beginning 44173 seconds after the burst and
continuing for about half an hour.  Observations were carried out under
good weather conditions at high airmass.

In 21 minutes of stacked exposures, we marginally detect a source within
the XRT error circle (Beardmore, Page, & Sakamoto, GCN 9914) at R ~ 20.5
+/- 0.3 (as compared to field stars using the USNO B1.0 catalog).  The
object is not found in the DSS catalog.  Variability can not be
established from these single-epoch observations.  It is likely that the
above source is the same identified by Hoversten & Sakamoto (GCN 9918). 
To establish the decay, follow-up observations are encouraged.

This message may be cited.


GRB_name: GRB090916A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9921
SUBJECT: Short-Duration GRB 090916: Skynet/PROMPT Observations
DATE:    09/09/17 02:52:44 GMT
FROM:    Josh Haislip at U.North Carolina  <haislip@physics.unc.edu>

J. Haislip, D. Reichart, K. Ivarsen, A. LaCluyze, A. Foster, J. Moore, A. 
Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. Nysewander 
report:

Skynet observed the Swift/BAT localization of short-duration GRB 090916 
(Troja et al., GCN 9913) with four of the 16" PROMPT telescopes at CTIO 
beginning 2.6 hours after the trigger in UVRI through high airmass.

We do not detect any uncatalogued sources.  Stacking only images that 
increase the limiting magnitude yields:

mean                                                    1-sig.   1-sig.
time                               3-sig.               sys.     stat.
since                              lim.     cal.        cal.     cal.
trig.   tel.       exp.     fil.   mag.     stars*      unc.     unc.
(h)                (# x s)                              (mag)    (mag)

2.7     PROMPT-3   6 x 80   U      17.7     14 SDSS 7   1.137    0.011
2.7     PROMPT-2   6 x 80   V      18.8     88 SDSS 7   0.020    0.001
2.7     PROMPT-5   6 x 80   I      18.6     56 SDSS 7   0.073    0.000
2.7     PROMPT-4   6 x 80   R      19.4     44 SDSS 7   0.005    0.000

* Transformed using Jester et al., 2005, ApJ, 130, 873.


GRB_name: GRB090915A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9923
SUBJECT: GRB 090915: GROND upper limits
DATE:    09/09/17 20:18:51 GMT
FROM:    Robert Filgas at MPI  <filgas@mpe.mpg.de>

P. Afonso (MPE Garching), A. Updike (Clemson University), J. Greiner and R.
Filgas (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 090915
(Cummings and Markwardt 2009, GCN #9912) simultaneously in the g'r'i'z'JHK
bands.

With 8 min total integration time in JHK and 7.7 min in g'r'i'z',
observations started on September 17, at 00:19 UTC (32.7 h = 117.8 ksec
after the burst) and were done at high air mass and under variable sky
conditions.

Inside the enhanced XRT error circle we do not detect the object reported
by Beardmore et al. (GCN #9914), Hoversten and Sakamoto (GCN #9918) and
Updike et al. (GCN #9920), down to the following limiting magnitudes (all
in the AB system):

g' > 23.7
r' > 23.2
i' > 22.7
z' > 21.3
J  > 21.1
H  > 20.2
K  > 19.2

The upper limits were obtained using SDSS and 2MASS catalogs
field stars as reference. No correction has been made for the expected
extinction corresponding to E(B-V) = 0.05 mag in the direction of the burst
(Schlegel et al. 1998).

The non-detection of the source suggests this was indeed the
afterglow of GRB 090915.


GRB_name: GRB090807A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9924
SUBJECT: GRB 090807: Skynet/DSO Observations
DATE:    09/09/18 06:01:13 GMT
FROM:    Josh Haislip at U.North Carolina  <haislip@physics.unc.edu>

J. Haislip, D. Reichart, A. Smith, D. Caton, L. Hawkins, K. Ivarsen, M. 
Schubel, A. LaCluyze, A. Foster, J. Moore, A. Oza, M. Schubel, J. Styblova, 
A. Trotter, J. A. Crain, and M. Nysewander report:

Skynet observed the Swift/BAT localization of GRB 090807 (Cannizzo et al., 
GCN 9746) with the 14" Dark Sky Observatory telescope in North Carolina 
beginning 10.4 hours after the trigger in I.

We do not detect the afterglow (Cannizzo et al., GCN 9746).  Stacking only 
images that increase the limiting magnitude yields:

mean                                                      1-sig.   1-sig.
time                               3-sig.                 sys.     stat.
since                              lim.     cal.          cal.     cal.
trig.   tel.     exp.       fil.   mag.     stars         unc.     unc.
(h)              (# x s)                                  (mag)    (mag)

10.7    DSO-14   10 x 160   I      18.9     807 USNO B1   0.489    0.000


GRB_name: GRB090916A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9925
SUBJECT: GRB 090916: Swift-XRT upper limit
DATE:    09/09/18 15:44:29 GMT
FROM:    Andy Beardmore at U Leicester  <apb@star.le.ac.uk>

A. P. Beardmore, K. L. Page (U. Leicester) and E. Troja (NASA/GSFC/ORAU)
report on behalf of the Swift-XRT team :

Due to a Moon constraint, the Swift-XRT could not observe the field of
the BAT short GRB 090916 (Troja et al., GCN Circ. 9913) until 9.3
hours after the trigger. In 12.3 ks of Photon Counting mode data (from
33.5 to 126.6 ks after the trigger) we do not detect any source
within the BAT refined error circle of Barthelmy et al. (GCN Circ. 9915).
The 3 sigma upper limit 0.3-10 keV count rate is 8 x 10^-4 count s^-1,
which corresponds to an observed flux limit of 3 x 10^-14 erg cm^-2 s^-1
(assuming a typical count-to-observed flux conversion factor of
3.8 x 10^-11 erg cm^-2 ct^-1, Evans  et al., 2009, MNRAS, 397, 1177).

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


GRB_name: GRB090726A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9926
SUBJECT: GRB 090726: Skynet/GORT Observations
DATE:    09/09/19 20:44:14 GMT
FROM:    Josh Haislip at U.North Carolina  <haislip@physics.unc.edu>

J. Haislip, D. Reichart, L. Cominsky, K. McLin, T. Graves, G. Spear, K. 
Ivarsen, A. LaCluyze, A. Foster, J. Moore, A. Oza, M. Schubel, J. Styblova, 
A. Trotter, J. A. Crain, and M. Nysewander report:

Skynet observed the Skynet/BAT localization of GRB 090726 (Page et al., GCN 
9706) with the 14" GORT telescope at Hume Observatory in California 
beginning 5.9 hours after the the trigger in I.

We do not detect the afterglow (Page et al., GCN 9707; Moskvitin, 
Fatkhullin & Valeev, GCN 9709).  Stacking only images that increase the 
limiting magnitude yields:

mean                                                   1-sig.   1-sig.
time                            3-sig.                 sys.     stat.
since                           lim.     cal.          cal.     cal.
trig.   tel.   exp.      fil.   mag.     stars         unc.     unc.
(h)            (# x s)                                 (mag)    (mag)

6.2     GORT   15 x 80   I      19.8     84 USNO B1    0.213    0.002
6.8     GORT   8 x 80    R      20.2     178 USNO B1   0.235    0.001


GRB_name: GRB090715B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9927
SUBJECT: GRB 090715B: Skynet/PROMPT Detections
DATE:    09/09/21 04:34:58 GMT
FROM:    Josh Haislip at U.North Carolina  <haislip@physics.unc.edu>

J. Haislip, D. Reichart, K. Ivarsen, A. LaCluyze, A. Foster, J. Moore, A. 
Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. Nysewander 
report:

Skynet observed the Swift/BAT localization of GRB 090715B (Vetere et al., 
GCN 9668) with three of the 16" PROMPT telescopes at CTIO beginning 3.1 
hours after the trigger in UBRI.

We detect the afterglow (Vetere et al., GCN 9668).  Stacking only images 
that increase the limiting magnitude yields:

mean                                                          1-sig. 
1-sig.
time                                                          sys.    stat.
since                                              cal.       cal.    cal.
trig.  tel.      exp.     fil.  magnitude          stars*     unc.    unc.
(h)              (# x s)                                      (mag)   (mag)

3.4    PROMPT-3  12 x 80  U     > 17.5 (3 sig.)    10 SDSS 7  0.094   0.001
3.8    PROMPT-5  40 x 80  I     19.80 +0.40 -0.29  93 SDSS 7  0.268   0.000
3.8    PROMPT-4  41 x 80  R     20.31 +0.20 -0.17  78 SDSS 7  0.151   0.000
4.0    PROMPT-3  29 x 80  B     > 20.8 (3 sig.)    37 SDSS 7  0.134   0.000

* Transformed using Jester et al., 2005, ApJ, 130, 873.


GRB_name: GRB090922A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9929
SUBJECT: GRB 090922A: Fermi GBM detection
DATE:    09/09/23 07:26:52 GMT
FROM:    Arne Rau at MPE  <arau@mpe.mpg.de>

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

"At 12:56:42.14  UT on 22 September 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090922A (trigger 275317004  / 090922539).

The on-ground calculated location, using the GBM trigger
data, is RA = 17.1, DEC = 74.3 (J2000 degrees,
equivalent to 17h 06m, 74d 18'), with an uncertainty
of 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 19 degrees.
Moreover, this burst was bright enough to result in
a Fermi spacecraft re-pointing maneuver.

The GBM light curve shows a bright peak of approximately 10s duration
followed by a weaker pulse approx. 60s later. The burst duration (T90) 
is 92 +/ 3 s (8-1000 keV).
The time-averaged spectrum of the main peak from T+0.003 s to T0+10.240 
s is
best fit by a Band function with Epeak = 139.3 +/- 6.6 keV,
alpha = -0.77 +/- 0.05, and beta = -2.28 +/- 0.07 (chi squared 1217/921 
d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(1.14 +/- 0.02)E-05 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+2.048 s in the 8-1000 keV band
is 15.6 +/- 0.04 ph/s/cm^2.

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


GRB_name: GRB090922A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9930
SUBJECT: GRB090922A: correction to Fermi location
DATE:    09/09/23 12:18:37 GMT
FROM:    Arne Rau at MPE  <arau@mpe.mpg.de>

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

"There has been a typo in the GBM localization of GRB 090922A (Rau, 
GCN#9929). The
correct location is:

RA=17.1deg (01h08min) and Dec=74.3deg (74d18')

with an uncertainty of 1 degree (radius, 1-sigma containment,  
statistical only; there is
additionally a systematic error which is currently estimated to be 2 to 
3 degrees).

I thank S. Holland for realizing this."


GRB_name: GRB090904B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9931
SUBJECT: GRB090904B : IRSF NIR upper limit
DATE:    09/09/25 02:00:32 GMT
FROM:    Kenta Nishimoto at Nagoya U/MOA-II  <nishimo@stelab.nagoya-u.ac.jp>

K. Nishimoto, T. Sako(Nagoya Univ.) on behalf of the MOA Collaboration,
M. Kurita on behalf of the IRSF Collabration, T. Yosikawa(Kyoto Univ.),
T. Suenaga(Soken Univ.) report:

We searched for a NIR afterglow of GRB090904B (GCN9881, V. D'Elia et
al.) starting from 17:6:57.7 UT on 2009 Sep 4 (15.71 hours after the burst)
with the SIRIUS on the IRSF 1.4m telescope at SAAO in South Africa.
In images of a 300sec exposure with J, H and Ks filter, we did not find
any object except the reported star (GCN9882, Covino et al and GCN9892,
Nishimoto et al.) within the error circle of the Swift XRT source
position (GCN9887, J.P. Osborne et al.).

Quick estimation of the limiting magnitude calibrated by using 2MASS
catalog:

J > 17.14
H > 16.57
K > 15.79


GRB_name: GRB090925A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9932
SUBJECT: GRB 090925: Fermi GBM detection
DATE:    09/09/25 14:54:03 GMT
FROM:    Elisabetta Bissaldi at MPE  <ebs@mpe.mpg.de>

E.Bissaldi and D.Gruber (all MPE) 
report on behalf of the Fermi GBM Team: 


"At 09:20:33.67 UT on 25 September 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090925 (trigger 275563235 / 090925389).
The on-ground calculated location, using the GBM trigger
data, is RA = 333.2, DEC = +14.3 (J2000 degrees,
equivalent to 22h 13m, 14d 18'), 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 116 degrees.

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

The GBM light curve consists of a FRED-like pulse
with a duration (T90) of about 50 s (8-1000 keV).
The time-averaged spectrum from T0-1 s to T0+20 s is
adequately fit by a Band function with
Epeak = 156 (+25/-20) keV, alpha = -0.60 (+0.14/-0.13),
and beta = -1.91 (+0.07/-0.09) (C-stat 369 for 357 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(9.46 +/- 0.26)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+6 s in the 8-1000 keV band is 4.2 +/- 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: GRB090926A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9933
SUBJECT: GRB 090926: Fermi GBM detection
DATE:    09/09/26 14:27:11 GMT
FROM:    Elisabetta Bissaldi at MPE  <ebs@mpe.mpg.de>

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


"At 04:20:26.99 UT on 26 September 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090926 (trigger 275631628 / 090926181).
The on-ground calculated location, using the GBM trigger
data, is RA = 354.5, DEC = -64.2 (J2000 degrees,
equivalent to 23h 38m, -64d 12'), with an uncertainty
of 1.0 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 48 degrees.
Moreover, this burst was bright enough to result in
a Fermi spacecraft repointing maneuver.

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

The GBM light curve consists of single pulse
with a duration (T90) of 20 +/- 2 s (8-1000 keV).
The time-averaged spectrum from T0 to T0+21 s is
best fit by a Band function with Epeak = 314 (+/- 4) keV,
alpha = -0.75 (+/-0.01) and beta = -2.59 (+0.04/-0.05)
(C-stat 1136 for 478 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(1.45 +/- 0.04)E-04 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+3 s in the 8-1000 keV band
is 80.8 +/- 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: GRB090926A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9934
SUBJECT: GRB 090926: Fermi LAT detection
DATE:    09/09/26 19:39:23 GMT
FROM:    Takeshi Uehara at Hiroshima U  <uehara@hirax7.hepl.hiroshima-u.ac.jp>

GRB 090926: Fermi LAT detection

Takeshi Uehara, Hiromitsu Takahashi (Hiroshima University) and
Julie McEnery (NASA/GSFC) report on behalf of the Fermi LAT team:

At 04:20:26.99 (UT) on 26 Sep 2009, the Fermi Large Area Telescope
(LAT) detected gamma rays from the long GRB 090926, which was
triggered and located by the Fermi Gamma-ray Burst Monitor (GBM)
(trigger 275631628 / 090926181, GCN9933). The angle of the GBM best
position (RA, Dec= 354.5, -64.2) with respect to the LAT boresight was
~52 degrees at the time of the trigger, which is close the edge of our
field of view.

The data from the Fermi LAT shows a significant increase in the event
rate within 2.5 degrees of the GBM location 7 s after the GBM trigger
that is spatially and temporally correlated with the GBM emission with
high significance. More than 150 photons above 100 MeV and more
than 20 photons above 1 GeV are observed up to more than 200 s after
the GBM trigger. The highest energy photon is a 19.6 GeV event which is
observed 26 seconds after the GBM trigger.

The best LAT on-ground localization is found to be (RA, Dec = 353.56,
-66.34) with a 90% containment radius of 0.07 deg (statistical; 68%
containment radius: 0.04 deg, preliminary systematic
error is less than 0.1 deg) which is consistent with the GBM localization.
A Swift TOO request has been issued.

Further analysis is ongoing.

The points of contact for this burst is

Takeshi Uehara : uehara@hep01.hepl.hiroshima-u.ac.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: GRB090926B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9935
SUBJECT: GRB 090926B: Swift detection of a burst
DATE:    09/09/26 22:20:28 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

D. Grupe (PSU), S. D. Barthelmy (GSFC), J. R. Cummings (NASA/UMBC),
J. A. Kennea (PSU), P. T. O'Brien (U Leicester),
P. Romano (INAF-IASFPA), M. Stamatikos (OSU/NASA/GSFC),
M. A. Stark (PSU) and L. Vetere (PSU) report on behalf of the Swift
Team:

At 21:55:48 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090926B (trigger=370791).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 46.318, -39.011 which is 
   RA(J2000)  = 03h 05m 16s
   Dec(J2000) = -39d 00' 40"
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 20 sec.  The peak count rate
was ~1600 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 21:57:16.8 UT, 88.3 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source located at RA, Dec 46.30693,
-39.00545 which is equivalent to:
   RA(J2000)  = 03h 05m 13.66s
   Dec(J2000) = -39d 00' 19.6"
with an uncertainty of 3.6 arcseconds (radius, 90% containment). 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
1.91e+20 cm^-2 (Kalberla et al. 2005). 

The initial flux in the 2.5 s image was 3.15e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 98 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 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: GRB090926A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9936
SUBJECT: GRB090926A: UVOT-enhanced XRT position
DATE:    09/09/27 00:26:28 GMT
FROM:    Loredana Vetere at PSU  <vetere@astro.psu.edu>

L. Vetere (PSU), P.A. Evans and M.R. Goad (U. Leicester) report
on behalf of the Swift-XRT team:

Using 3190 s of XRT Photon Counting mode data and 4 UVOT
images, 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 =353.40070, -66.32390 which is equivalent to:

RA (J2000):  23 33 36.18
Dec (J2000): -66 19 25.9

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, MNRAS, 397, 1177).

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


GRB_name: GRB090926A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9937
SUBJECT: GRB 090926A: Skynet/PROMPT Discovery of the Optical Afterglow
DATE:    09/09/27 01:36:29 GMT
FROM:    Josh Haislip at U.North Carolina  <haislip@physics.unc.edu>

J. Haislip, D. Reichart, K. Ivarsen, A. LaCluyze, A. Foster, J. Moore, A. 
Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. Nysewander 
report:

Skynet observed the Fermi/LAT localization of GRB 090926A (Uehara et al., 
GCN 9934) with four of the 16" PROMPT telescopes at CTIO beginning 19.0 
hours after the trigger in UBVRI.

We detect an optical source within the Swift/XRT localization (Vetre et 
al., GCN 9936) that is not in the DSS (POSS-II Red), at

RA = 23:33:36.02
DEC = -66:19:26.5

Stacking only images that increase the limiting magnitude yields:

mean
time
since                                              cal.
trig.  tel.      exp.     fil.  magnitude          stars
(h)              (# x s)

19.9   PROMPT-2  22 x 80  V     18.81 +0.10 -0.09  52 NOMAD
20.0   PROMPT-5  22 x 80  I     18.24 +0.04 -0.04  165 USNO B1
20.0   PROMPT-4  24 x 80  R     18.06 +0.03 -0.03  230 USNO B1


GRB_name: GRB090926A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9938
SUBJECT: GRB 090926A: Swift/UVOT detection of an optical afterglow
DATE:    09/09/27 02:10:34 GMT
FROM:    Caryl Gronwall at PSU/Swift-UVOT  <caryl@astro.psu.edu>

C. Gronwall (PSU) and L. Vetere (PSU) report on behalf of the
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 090926A
approximately 13 hours after the Fermi/GBM trigger (Bissaldi,
GCN Circ. 9933).  In a 357 sec observation in the white filter, we
find a candidate optical afterglow within the XRT error circle (Vetere
et al., GCN Circ. 9936) at
  RA(J2000) =  23:33:36.037 = 353.400154
  Dec(J2000) = -66:19:26.64 = 66.324067
with a 90%-confidence error radius of about 0.11 arc sec. This position
is 0.99 arc sec. from the center of the XRT error circle and is  
consistent
with the optical afterglow position found by Skynet/PROMPT (Haislip et
al., GCN Circ. 9937).  The estimated magnitude is 18.78 +/- 0.04.
This value is not corrected for the Galactic extinction due to the
reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB090926B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9939
SUBJECT: GRB 090926B: Swift-BAT refined analysis
DATE:    09/09/27 03:51:16 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <james.r.cummings@nasa.gov>

W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC),
J. R. Cummings (GSFC/UMBC), D. Grupe (PSU), 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+243 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 090926 (trigger #370791)
(Grupe, et al., GCN Circ. 9935).  The BAT ground-calculated position is
RA, Dec = 46.310, -38.997 deg which is
    RA(J2000)  =  03h 05m 14.3s
    Dec(J2000) = -38d 59' 50.9"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 26%.

The mask-weighted light curve shows a sharp rise at T-20 sec, then a
complex peak reaching a maximum at T-1 sec, followed by an approximately
exponential decay. T90 (15-350 keV) is 109.7 +- 11.3 sec (estimated 
error including systematics).

The time-averaged spectrum from T-21.6 to T+133.2 sec is best fit by a
power law with an exponential cutoff.  This fit gives a photon index
0.52 +- 0.24, and Epeak of 78.3 +- 7.0 keV (chi squared 57.75 for 56
d.o.f.).  For this model the total fluence in the 15-150 keV band is
7.3 +- 0.2 x 10^-06 erg/cm2 and the 1-sec peak flux measured from
T-1.31 sec in the 15-150 keV band is 3.2 +- 0.3 ph/cm2/sec.  A fit to a
simple power law gives a photon index of 1.54 +- 0.00 (chi squared
125.34 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/370791/BA/


GRB_name: GRB090926B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9940
SUBJECT: GRB 090926B: Swift XRT refined analysis 
DATE:    09/09/27 04:16:40 GMT
FROM:    Dirk Grupe at PSU/Swift-XRT  <grupe@astro.psu.edu>

D. Grupe (PSU), P.A. Evans and M.R. Goad (U. Leicester) report
on behalf of the Swift-XRT team:

We have analysed  the first two orbits of XRT data of GRB090926B
(Grupe et al. GCN Circ.  9935). The data comprise 307 s in Windowed
  Timing (WT) mode and 1985 s in Photon Counting (PC) mode.


Using 1692 s of XRT Photon Counting mode data and 1 UVOT
images, 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 =
46.30840, -39.00600 which is equivalent to:

RA (J2000):  03 05 14.01
Dec (J2000): -39 00 21.5

with an uncertainty of 1.7" (radius, 90% confidence). This
position is 32.7" from the BAT ground-calculated position given in
Baumgartner et al (GCN circular 9939).

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, MNRAS, 397, 1177).

A spectrum formed from the WT mode data can be fitted with an
absorbed  power-law with a photon spectral index of 1.84+/-0.07
with an   absorption column of (1.70+/-0.22)e21 cm^-2 which is in
excess of the Galactic value of 1.91 x 10^20 cm^-2 (Kalberla et al.
2005). The PC mode spectrum results is a slightly flatter X-ray
spectrum with Gamma = 1.58+0.22-0.20. The absorption column density,
however, is consistent with the WT result. Based on the excess
absorption, according to Grupe et al. (2007, AJ, 133, 2216), the
redshift of this burst is most likely less than 4.0.


The light curve can be modelled with a broken power-law decay with an
index of alpha=2.00+/-0.05, followed by a break at T+712+190/-160 s
to  an alpha of 1.23 (-0.17, +0.07). If the afterglow continues to
dacay with a slope of 1.23, the predicted count rate 24 hours after
the trigger is 3.4e-3 counts s^-1 or 1.6e-13 ergs s^-1 cm^-2.


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


GRB_name: GRB090926B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9941
SUBJECT: GRB 090926B: NOT optical observation
DATE:    09/09/27 05:05:31 GMT
FROM:    Dong Xu at DARK,NBI  <dong@astro.ku.dk>

D. Xu, D. Malesani (DARK/NBI), S. Barros (Queen Univ., Belfast), P. 
Jakobsson (Univ. Iceland), report on behalf of a larger collaboration.

We observed the field of GRB 090926B (Grupe et al., GCN 9935) with the 
NOT equipped with ALFOSC. Observations were carried out in the R and I 
bands, at high airmass (~2.5), starting on 2009 Sep 27.122 UT (4.99 hr 
after the GRB) and 27.146 UT (5.58 hr after the GRB), respectively.

No source is visible inside the enhanced X-ray error circle (Grupe et 
al., GCN 9940; http://www.swift.ac.uk/xrt_positions), down to a limiting 
magnitude R ~ 23 based on USNO-B1 stars in the field.


GRB_name: GRB090926A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9942
SUBJECT: GRB 090926A: VLT/X-shooter redshift
DATE:    09/09/27 06:48:04 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@astro.ku.dk>

D. Malesani (DARK/NBI), P. Goldoni (APC/Univ. Paris 7 and SAp/CEA), J. 
P. U. Fynbo (DARK/NBI), V. D'Elia (ASDC and INAF/OAR), S. Covino 
(INAF/OABr), H. Flores (Paris Obs.), A.J. Levan (Univ. Warwick), S. D. 
Vergani (APC/Univ. Paris 7), K. Wiersema (Univ. Leicester), report on 
behalf of the X-shooter GRB collaboration:

We observed the afterglow of GRB 090926A (Bissaldi, GCN 9933; Uehara et 
al., GCN 9934; Vetere et al., GCN 9936; Haislip et al., GCN 9937) with 
the X-shooter spectrograph mounted on the ESO-VLT UT2. Observations were 
taken as part of the instrument Science Verification phase. X-shooter is 
a broad-band single-object spectrograph covering the wavelength range 
from the UV to the infrared (3300-22000 AA).

At the beginning of the observation (22.0 hr after the GRB), the 
afterglow had R = 17.9 as measured from the acquisition image. Four 
spectra lasting 1800 s each were secured.

The spectrum has high signal to noise and shows a wealth of absorption 
features, together with a broad depression around 3780 AA, which we 
interpret as a DLA. We identify CIV 1548 and 1550, Si II 1304 and 1526, 
SiII* 1533, FeII 1608, MgII 2798 and 2803, and several others, from 
which we measure a redshift z=2.1062. We caution that the wavelength 
solution is based on archival calibration data.

We thank the ESO observing staff, in particular Joel Vernet, Thomas 
Bensby, and Stephane Brillant.


GRB_name: GRB090926B
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9943
SUBJECT: GRB 090926B: MAXI GSC detection
DATE:    09/09/27 07:27:48 GMT
FROM:    Nobuyuki Kawai at Tokyo Tech  <nkawai@hp.phys.titech.ac.jp>

M. Morii (Tokyo Tech), M. Nakajima (Nihon U.), M. Matsuoka,
K. Kawasaki, S. Ueno, H. Tomida, M. Suzuki, M. Ishikawa (JAXA),
T. Mihara, M. Kohama, Y.E. Nakagawa, M. Sugizaki, T. Yamamoto (RIKEN), 
N. Kawai, K. Sugimori (Tokyo Tech), A. Yoshida, K. Yamaoka, 
S. Nakahira (AGU), H. Tsunemi, M. Kimura (Osaka U.), H. Negoro, 
S. Miyoshi, H. Ozawa, R. Ishiwata, (Nihon U.), Y. Ueda, N. Isobe, 
S. Eguchi, K. Hiroi (Kyoto U.) report on behalf of the MAXI team:

The Gas Slit Camera (GSC) of MAXI, the all-sky X-ray monitor on the ISS,
detected a bright X-ray source at the position consistent with GRB 090926B
(Grupe et al, GCN Circ. 9935) in the energy range of 2-30 keV.
The nominal location of the source as measured by GSC is 

(R.A., Dec.) = (46.3 deg, -39.1 deg) = (03:05:12, -39:06:00)(J2000) 

with an estimated systematic uncertainty of about 1 degree.

The start time of the source detection (above 3 sigma level) was
21:55:31 UT on 26 September 2009, and seen until 21:55:55 UT.
The start time was 17 sec earlier than the Swift-BAT trigger time,
approximately consistent with the rise epoch (T-20) reported in the BAT 
refined analysis (Baumgartner et al., GCN Circ. 9939).

The X-ray flux at the peak was about 0.3 Crab (uncorrected).
There are significant time structures within the transit light curve, 
which would be simply triangular for a steady source.

The all-sky image and the light curve is shown at the MAXI web site
http://maxi.riken.jp/ at the "News" section.

MAXI is currently in the commissioning phase that runs for three months.
The systematic uncertainty in localization will be significantly improved
with the progress of the alignment calibration.


GRB_name: GRB090926B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9944
SUBJECT: GRB 090926B: optical object in error circle
DATE:    09/09/27 07:45:32 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@astro.ku.dk>

Daniele Malesani, Johan P. U. Fynbo (DARK/NBI) and V. D'Elia (ASDC and 
INAF/OAR) report on behalf of a larger collaboration:

We observed the field of GRB 090926B (Grupe et al., GCN 9935; Morii et 
al., GCN 9943) with the VLT UT1 equipped with FORS2. Seeing was 
0.8-0.9". Preliminary inspection of the image reveals a faint, slightly 
extended source at a position consistent with the revised XRT error 
circle (Grupe et al., GCN 9940; http://www.swift.ac.uk/xrt_positions). 
Its coordinates are (0.5" error):

RA(J2000) = 03:05:13.94
Dec(J2000) = -39:00:22.2

and its magnitude (based on archival zeropoints) is R ~ 23 on 2009 Sep 
27.246 UT (7.97 hr after the GRB). Inspection of the NOT images (Xu et 
al., GCN 9941) reveals a faint nebulosity, with a luminosity level 
consistent with the VLT measurement.

Presently, it is not clear whether this source is related to the GRB or 
not. It may be the host galaxy, or the blend of two faint, adjacent 
objects. Further observations are planned to evaluate its variability.

We gladly acknowledge excellent support from the ESO observing staff 
during a busy night, in particular Yuri Beletsky, and Stephane Brillant.


GRB_name: GRB090927A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9945
SUBJECT: GRB 090927: Swift detection of a short burst
DATE:    09/09/27 10:19:48 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

D. Grupe (PSU), J. R. Cummings (NASA/UMBC), C. Gronwall (PSU),
C. Guidorzi (U Ferrara), C. B. Markwardt (CRESST/GSFC/UMD),
P. T. O'Brien (U Leicester), K. L. Page (U Leicester),
D. M. Palmer (LANL), P. Romano (INAF-IASFPA), M. H. Siegel (PSU),
T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU) report on behalf of the
Swift Team:

At 10:07:16 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090927 (trigger=370846). The BAT on-board calculated 
location is RA, Dec 343.953, -70.978 which is 
   RA(J2000) = 22h 55m 49s
   Dec(J2000) = -70d 58' 38"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single peak
structure with a duration of about 1.5 sec.  The peak count rate
was ~4000 counts/sec (15-350 keV), at ~1 sec after the trigger. 

Due to an observing constraint, Swift will not slew until 
T0+33.8 minutes. There will be no XRT or UVOT data until
this time. 

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: GRB090927A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9946
SUBJECT: GRB 090927: Swift/UVOT detection of an optical afterglow
DATE:    09/09/27 10:58:19 GMT
FROM:    Caryl Gronwall at PSU/Swift-UVOT  <caryl@astro.psu.edu>

C. Gronwall and D. Grupe (PSU) report on behalf of the Swift/UVOT team:

In response to GRB090927 (Swift/BAT trigger 370846) at 10:07:16 UT,
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 2141 seconds after the BAT trigger. There is a candidate  
afterglow in
the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 22:55:53.41 = 343.97255
DEC(J2000) = -70:58:49.3 = -70.98037
with a 90%-confidence error radius of about 0.63 arc sec. This  
position is 7.2
arc sec. from the center of the XRT error circle. The estimated  
magnitude is
19.10 with a 1-sigma error of about 0.15. No correction has been made  
for the
expected extinction corresponding to E(B-V) of 0.03.


GRB_name: GRB090926B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9947
SUBJECT: GRB 090926B: VLT spectroscopy
DATE:    09/09/27 11:21:59 GMT
FROM:    Pall Jakobsson at U of Iceland  <pja@raunvis.hi.is>

Johan P. U. Fynbo, Daniele Malesani (DARK/NBI), Pall Jakobsson
(U. Iceland) and Valerio D'Elia (ASDC and INAF/OAR) report on
behalf of a larger collaboration:

We observed the afterglow of GRB 090926B (Grupe et al, GCN 9935;
Morii et al., GCN 9943). Using FORS2 on the Very Large Telescope,
we have obtained 3*30 min spectra (300V grating) of the optical
afterglow candidate (Malesani et al., GCN 9944). Observations
commenced roughly 8 hours after the burst.

The combined spectrum shows an emission line, presumably
corresponding to [O II] 3727 at z = 1.24. At his redshift we
find several other absorption features, including Mg II, Fe II
and Al III. Hence, we interpret the spectrum as a combination
of the GRB afterglow and the host galaxy.

We acknowledge excellent support from the ESO observing staff,
in particular Yuri Beletsky and Stephane Brillant.


GRB_name: GRB090926A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9948
SUBJECT: GRB090926A: Swift/UVOT observations
DATE:    09/09/27 12:41:56 GMT
FROM:    Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>

S. R. Oates (MSSL-UCL) and L. Vetere (PSU) report on behalf
of the Swift/UVOT team:

The Swift/UVOT began observerving the field of Fermi GRB 090926A
47ks after the Fermi  GBM and LAT trigger (Bissaldi., GCN Circ. 9933;
Uehara ., GCN Circ. 9934). We detect a fading optical afterglow in  
white,
v and u filters at the position reported by UVOT (Gronwall et al.,
GCN Circ. 9938) and Skynet/PROMPT (Haislip et al., GCN Circ 9937).
The lightcurve appears to rebrighten from 70ks to the end of
current observations.

Preliminary magnitudes are reported below.

Filter  T_start(s) T_stop(s)  Exposure      Mag  Err
-------------------------------------------------------
white     46977     47341      358       18.71 +/- 0.04
white     69902     70369      459       19.32 +/- 0.05
v         47348     47712      358       18.45 +/- 0.16
u         46608     46972      358       18.21 +/- 0.07
u         69429     69896      459       18.85 +/- 0.09
u         86050     86613      554       18.52 +/- 0.07
-------------------------------------------------------

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


GRB_name: GRB090926B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9949
SUBJECT: GRB090926B: Swift/UVOT Upper Limits
DATE:    09/09/27 12:42:23 GMT
FROM:    Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>

S. R. Oates (MSSL-UCL) and D. Grupe (PSU) report on behalf of the  
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of
GRB 090926B 98s after the BAT trigger (Grupe et al., GCN 9935).
We do not detect any source at the position reported by
VLT (Malesani et al., GCN 9944) and the enhanced Swift XRT
position (Grupe et al. GCN 9940).

The 3-sigma upper limits for the finding charts (FC) and summed images  
are:

Filter   T_start   T_stop   Exp(s)  Mag (3-sigma upper limit)
-------------------------------------------------------------
white(FC)  98       248      147       > 21.02
white      591      2053     303       > 21.21
v    641      2103     175       > 19.19
b    567      5976     226       > 20.32
u(FC)      310      560      246       > 20.30
u    715      5900     333       > 20.22
uvw1    691      5695     333       > 20.25
uvm2    5290     5490     197       > 19.77
uvw2    616      1389     58        > 19.09
-------------------------------------------------------------

The quoted upper limits have not been corrected for the expected
Galactic extinction along the line of sight of E_(B-V) = 0.02 mag.
All photometry is on the UVOT photometric system described in Poole et
al. (2008, MNRAS, 383, 627).


GRB_name: GRB090927A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9950
SUBJECT: GRB 090927: Enhanced Swift-XRT position
DATE:    09/09/27 13:41:20 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 1424 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 090927, 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 = 343.97291, -70.98032 which is equivalent
to:

RA (J2000): 22h 55m 53.50s
Dec (J2000): -70d 58' 49.2"

with an uncertainty of 2.0 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, MNRAS, 397, 1177).

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


GRB_name: GRB090926A
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9951
SUBJECT: GRB 090926A: Suzaku WAM observation of the prompt emission
DATE:    09/09/27 14:52:07 GMT
FROM:    Kazuhiro Noda at Miyazaki U  <kaz1206@astro.miyazaki-u.ac.jp>

K. Noda, E. Sonoda, N. Ohmori, K. Kono, H. Hayashi,
A. Daikyuji, Y. Nishioka, M. Yamauchi (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 very bright, Fermi-LAT detected GRB 090926A (Fermi-GBM trigger 
#275631628/ 090926181; Bissaldi, GCN 9933; Uehara et al., GCN 9934)
triggered the Suzaku Wide-band All-sky Monitor (WAM) 
which covers an energy range of 50 keV - 5 MeV at 04:20:27.168 UT (=T0).

The observed light curve shows a multi-peaked structure, lasting from
 T0-0.5 s to T0+16.5 s, followed by a weak tail seen up to ~T0+34.5s.
 The total duration (T90) was about 13 s and the fluence in
 100 - 1000 keV was 9.71(-0.40, +0.22)x 10-5 erg/cm2.
The 1-s peak flux measured from T0+3.5 s was 30.6(-2.3, +1.6) photons/cm2/s
in the same energy range.

Preliminary result shows that the time-averaged spectrum from
T0-0.5 s to T0+34.5 s is well fitted by a GRB Band model as follows.
the low-energy photon index alpha: -1.09 (-0.27, +0.37),
the high-energy photon index beta: -2.63 (-0.17, +0.11),
and the peak energy Epeak: 434 (-30, +32) keV (chi2/d.o.f = 29.7/23).

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


GRB_name: GRB090927A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9952
SUBJECT: GRB 090927: Swift XRT refined analysis 
DATE:    09/09/27 15:13:01 GMT
FROM:    Dirk Grupe at PSU/Swift-XRT  <grupe@astro.psu.edu>

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

Due to an observing constraint, the Swift XRT started observing the
field of GRB 090927 Grupe et al., GCN Circ. 9945) delayed at 10:43:03
UT, 2147s after the BAT trigger.

XRT found a faint, fading, uncatalogued X-ray source at
RA (J2000): 22h 55m 53.50s
Dec (J2000): -70d 58' 49.2"

with an uncertainty of 2.0 arcsec (radius, 90% confidence) as given
in Evens et al. (GCN Circular 9950).  This location is 24.8" from
the BAT on-board calculated location (Grupe et al., GCN Circular
9945), inside the BAT error circle, and 0.5" from the UVOT position
given in Gronwall & Grupe (GCN Circular 9946).

Based on the Photon Counting mode (pc) mode data of the first orbit
with an exposure time of 1421s we extracted a spectrum which can be
fitted with a single absorbed power law model with Gamma =
1.64+/-0.49 and an absorption column density consistent with the
Galactic value of 2.92 x 10^20 cm^-2 (Kalberla et al. 2005).

The light curve can be modelled with a single power-law decay with
an index of alpha=1.76+2.05/-0.96. If the afterglow continues to
decay with this slope the predicted count rate 24 hours after
the trigger is 2.5e-4 counts s^-1 or 1.3e-14 ergs s^-1 cm^-2.

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


GRB_name: GRB090926A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9953
SUBJECT: GRB 090926A: Skynet/PROMPT Continued Observations
DATE:    09/09/27 18:49:04 GMT
FROM:    Josh Haislip at U.North Carolina  <haislip@physics.unc.edu>

J. Haislip, D. Reichart, K. Ivarsen, A. LaCluyze, A. Foster, J. Moore, A. 
Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. Nysewander 
report:

Skynet continued to observe the afterglow (Haislip et al., GCN 9937) of GRB 
090926A (Bissaldi, GCN 9933) with four of the 16" PROMPT telescopes at CTIO 
throughout the night in BVRI.

We find that the light curve brightens from the beginning of our 
observations (about 19 hours after the trigger) to about 1 day after the 
trigger in all bands, which is consistent with the findings of Oates & 
Vetere (GCN 9948) in UVOT's u band.

Around 1 day, the light curve peaks at R = 17.8 mag (calibrated to 82 USNO 
B1 stars) and begins to fade.  A second, smaller rebrightening begins 
around 26 hours and peaks at R = 18.0 mag around 27 hours.


GRB_name: GRB090927A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9954
SUBJECT: Swift/UVOT observations of GRB 090927
DATE:    09/09/27 18:58:12 GMT
FROM:    Paul Kuin at MSSL  <npkuin@googlemail.com>

N.P.M. Kuin (MSSL-UCL) and D. Grupe (PSU) report on behalf
of the Swift/UVOT team:

The Swift/UVOT began a delayed observing the field of GRB 090927
2121s after the trigger due to an observing constraint (Grupe, GCN
Circ. 9945). We detect a fading optical afterglow in white, v,b,
and u filters at the position reported by UVOT (Gronwall et al.,
GCN Circ. 9946).

Preliminary magnitudes are reported below.

Filter   T_start(s) T_stop(s) Exposure(s) Magnitude
===================================================
white(FC)    2141    2291    147.4    19.13 +/- 0.09
white        2372    2920    235.6    19.40 +/- 0.09
v            2121    2617     48.6    19.0  +/- 0.37
v            3131    3331    196.6    19.37 +/- 0.25
b            2348    2542     38.9    19.50 +/- 0.31
b            2696    2716     19.5    19.09 +/- 0.34
u            2323    2517     38.9    18.77 +/- 0.26
u            2671    2691     19.5   >18.89
uvw1         2299    3576     92.8   >19.63
uvm2         2446    3536    235.6   >19.89
uvw2         2397    2592     38.9   >18.84
====================================================

The above magnitudes are not corrected for the Galactic extinction
corresponding to a reddening of E_{B-V} = 0.03 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).


GRB_name: GRB090927A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9955
SUBJECT: GRB 090927, Swift-BAT refined analysis of the possibly short burst
DATE:    09/09/27 19:36:02 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <james.r.cummings@nasa.gov>

M. Stamatikos (OSU), 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), J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):

Using the data set from T-239 to T+963 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 090927 (trigger #370846)
(Grupe, et al., GCN Circ. 9945).  The BAT ground-calculated position is
RA, Dec = 343.929, -70.973 deg which is
    RA(J2000)  =  22h 55m 42.9s
    Dec(J2000) = -70d 58' 24.2"
with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 55%.

The mask-weighted light curve shows a single irregular peak with an
overall roughly FRED shape.  T90 (15-350 keV) is 2.2 +- 0.4 sec 
(estimated error including systematics).

The time-averaged spectrum from T+0.0 to T+2.4 sec is best fit by a
simple power-law model.  The power law index of the time-averaged
spectrum is 1.80 +- 0.20.  The fluence in the 15-150 keV band is
2.0 +- 0.3 x 10^-07 erg/cm2.  The 1-sec peak photon flux measured from
T-0.01 sec in the 15-150 keV band is 2.0 +- 0.2 ph/cm2/sec.  All the
quoted errors are at the 90% confidence level.

The classification of this burst as short or long is not clear.  The
burst appears to have significant lag between energy bands, and
moreover is not particularly hard.  We expect to perform a more
quantitative lag analysis and report the results in an additional
circular.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/370846/BA/


GRB_name: GRB090927A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9956
SUBJECT: GRB 090927: Zadko Telescope observations
DATE:    09/09/27 20:29:05 GMT
FROM:    Alain Klotz at CESR-CNRS  <Alain.Klotz@free.fr>

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

A. Klotz (CESR, OHP), 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, M. Laas (OHP), P. Thierry (Airbus)

The 1.0m F/4 Zadko telescope started imaging
the field of GRB 090927 (trigger=370846, Grupe
et al., GCN 9945) 110 minutes after the Swift
trigger. A fading source was found within the
XRT error circle (GCN 9946, Gronwall et al.).
The field was observed for 50 minutes using a
preliminary version of a robotic observation
mode.

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

tmid(min) Exp. Time  R Magnitude
-------------------------------------
110           42s    >16
126          540s     19.8 +/- 0.5
158          360s     20.0 +/- 0.5

The fading seems to have low decay
which is encouraging to perform
spectrocopy in the next hours.


GRB_name: GRB090926B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9957
SUBJECT: GRB 090926B: Fermi GBM detection
DATE:    09/09/28 01:34:51 GMT
FROM:    Michael S. Briggs at UAH and MSFC  <michael.briggs@nasa.gov>

Michael S. Briggs (UA Huntsville), reports on behalf of the Fermi GBM Team:

"At 21:55:28.53 UT on 26 Sept 2009, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 090926B (trigger 275694930  / 090926.914),
which also triggered the Swift BAT 19 seconds later (D. Grupe et al.,
GCN 9935).   The GBM location is consistent with the Swift BAT location.
The angle from the Fermi LAT boresight is approximately 100 degrees.

The GBM light curve shows multiple peaks with a duration (T90)
of 81 +/- 13 s (10 to 1000 keV). The time-averaged spectrum from T0 to
T0+48.6 s is best fit by cutoff power law with Epeak = 91 +/- 2 keV and 
index
= -0.13 +/- 0.06.   The fluence (10 to 1000 keV) in this time interval is
(8.7 +/- 0.3)E-06 erg/cm^2.

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


GRB_name: GRB090927A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9958
SUBJECT: GRB 090927: VLT redshift
DATE:    09/09/28 07:44:23 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@astro.ku.dk>

Andrew J. Levan (Univ. Warwick), Johan P.U. Fynbo (DARK/NBI), Jens 
Hjorth (DARK/NBI), Daniele Malesani (DARK/NBI), Paolo D'Avanzo 
(INAF/OABr), Valerio D'Elia (INAF/OAR), report on behalf of a larger 
collaboration:

We observed the afterglow of GRB 090927 (Grupe et al., GCN 9945; 
Gronwall et al., GCN 9946), possibly short (Stamatikos et al., GCN 
9955). Using FORS2 on the Very Large Telescope, we have obtained 3x30 
min spectra (300V grism) of the optical afterglow (Gronwall & Grupe, GCN 
9946; Klotz et al., GCN 9956). Observations started on Sep 27.11 UT, 
about 16.5 hr after the burst. The afterglow had a magnitude R ~ 21.7 as 
measured from the acquisition images.

The obtained spectrum shows Mg II and Fe II absorption lines 
corresponding to z = 1.37. There is no evidence for higher redshift 
systems or a Lyman-alpha and hence z = 1.37 is the likely redshift of 
GRB 090927.

We acknowledge excellent support from the ESO observing staff, in 
particular Yuri Beletsky and Stephane Brillant.


GRB_name: GRB090926A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9959
SUBJECT: Konus-Wind and Konus-RF observations of GRB 090926A
DATE:    09/09/28 16:42:28 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, and D. Svinkin on behalf of
the Konus-Wind and Konus-RF teams, and
T. Cline on behalf of the Konus-Wind team, report:

The long bright GRB 090926A (Fermi-GBM trigger 275631628 / 090926181: 
Bissaldi, GCN 9933) localized by Fermi-LAT (Uehara et al., GCN 9934) 
triggered Konus-Wind at T0=15628.683 s UT (04:20:28.683).
It was also detected by Konus-RF instrument onboard CORONAS-PHOTON s/c 
in the waiting mode while being at high latitudes.

The burst light curve shows a multipeaked structure with a total 
duration of ~16 s, followed by a weak tail seen up to ~T0+50 s.

As observed by Konus-Wind the burst
had a fluence of 1.80(-0.07, +0.08)x10^-4 erg/cm2,
and a 16-ms peak flux measured from T0+8.944 s
of 2.91(-0.54, +0.56)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+26.880 s) can be fitted (in the 20 keV - 10 MeV
range) by GRB (Band) model for which:
the low-energy photon index alpha = -0.76 +/- 0.03,
the high energy photon index beta = -2.59(-0.13, +0.10),
the peak energy Ep = 321 +/- 12 keV (chi2 = 106.0/84 dof).
The emission is clearly seen up to ~10 MeV.

All the quoted errors are at the 90% confidence level.

Assuming z = 2.1062 (Malesani et al., GCN 9942)
and a standard cosmology model with H_0 = 70 km/s/Mpc, Omega_M = 0.27,
Omega_\Lambda = 0.73, the isotropic energy release E_iso ~2.0x10^54 erg,
the peak luminosity (L_iso)_max ~ 1.0x10^54 erg/s, and Ep_rest ~1000 keV.

The Konus-Wind light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB090926_T15628/


GRB_name: GRB090927A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9960
SUBJECT: GRB 090927: Faulkes Telescope South Detection of the Optical  Afterglow
DATE:    09/09/28 16:42:32 GMT
FROM:    Zach Cano at ARI/John Moores Liverpool  <zec@astro.livjm.ac.uk>

Z. Cano, A. Melandri, C. Mundell, D. Bersier, R.J. Smith, I. A. Steele, S.
Kobayashi, C.J. Mottram (Liverpool JMU), A. Gomboc (U. Ljubljana) report,
on behalf of the Liverpool GRB group:

The Faulkes Telescope South (Australia) observed the field of GRB
090927 (Swift trigger=370846, Grupe et al., GCN 9945) on 2009 September 27
and 28.

The afterglow candidate reported by Gronwell & Grupe (GCN 9946) is clearly
visible and fading at position:

RA(J2000):   22 55 53.42
Dec(J2000): -70 58 49.54

with the following magnitudes calibrated wrt USNO-B1 objects in the field:

I = 19.4 +/- 0.1  @ 3.66 hrs
I = 21.3 +/- 0.2  @ 27.23 hrs

R = 19.9 +/- 0.1 @ 4.21 hrs

Observations are on-going, but we derive preliminary decay rates using the
above FTS measurements and the R-band magnitude reported by Levan et al.
(GCN 9958) to be: alpha_I=0.9+/-0.2, alpha_R=1.2+/-0.2.


GRB_name: GRB090926A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9961
SUBJECT: GRB090926A: Swift-XRT refined analysis 
DATE:    09/09/28 21:59:52 GMT
FROM:    Loredana Vetere at PSU  <vetere@astro.psu.edu>

L. Vetere (PSU) reports on behalf of the Swift-XRT team:

We have analyzed the first 21.8 ks of Swift-XRT data of FERMI
GRB090926A (Bissaldi et al., GCN Circ. 9933). The UVOT-enhanced XRT
position for this burst was given in GCN Circ.9936 (Vetere et al.).

The data are entirely in Photon Counting (PC) mode from T+46.7 ks
to T+203 ks. The light curve shows a decaying behaviour with some
flaring activity. It is best fitted by a power-law with decay index
1.29+/-0.2. Assuming the X-ray emission from the burst continues
to decline at the present rate, the predicted count rate at T+3d
is 0.009 cts/s.

The average spectrum is best fit by an absorbed power-law model
with a photon spectral index of 2.6 (+0.3,-0.2) and an absorption
column density of 1.0 (+0.5,-0.3)e21 cm-2 in excess of the Galactic
value of 2.7e20 cm-2 (Kalberla et al. 2005). The counts-to-observed
0.3-10 keV flux conversion factor deduced from this spectrum is
3.5e-11 erg cm-2 count-1. The average observed (unabsorbed) fluxes
are 1.3 (1.9)E-12 ergs cm-2 s-1. Errors are given at the 90%
confidence level.

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


GRB_name: GRB090929A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9962
SUBJECT: GRB 090929A: Fermi GBM detection
DATE:    09/09/29 07:46:14 GMT
FROM:    Arne Rau at MPE  <arau@mpe.mpg.de>

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

"At 04:33:03.97  UT on 29 September 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090929A (trigger 275891585  / 090929190).

The on-ground calculated location, using the GBM trigger
data, is RA = 51.7, DEC = -7.3 (J2000 degrees,
equivalent to 03h 27m, -07d 18'), 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 122 degrees.

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

The GBM light curve consists of multiple short peaks
with a duration (T90) of about 8.5 +/- 0.4 s (8-1000 keV).
The time-averaged spectrum from T0+0.002s to T0+4.896s is
best fit by a power law function with an exponential
high energy cutoff.  The power law index is -0.52 +/- 0.06 and
the cutoff energy, parameterized as Epeak, is 610.9 +/- 44.5 keV
(chi squared 439 for 393 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(1.06 +/- 0.03)E-05 erg/cm^2. The 1.822-sec peak photon flux measured
starting from T0+0.002 s in the 8-1000 keV band is 10.9 +/- 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: GRB090929B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9963
SUBJECT: GRB 090929B: Swift detection of a burst
DATE:    09/09/29 10:37:12 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

C. Pagani (PSU), A. P. Beardmore (U Leicester), S. Campana (INAF-OAB),
V. D'Elia (ASDC), C. Gronwall (PSU), D. Grupe (PSU),
C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC),
N. P. M. Kuin (MSSL), J. Mao (INAF-OAB), P. T. O'Brien (U Leicester),
J. P. Osborne (U Leicester), K. L. Page (U Leicester),
D. M. Palmer (LANL), P. Romano (INAF-IASFPA),
B. Sbarufatti (INAF-IASFPA), T. N. Ukwatta (GSFC/GWU) and
L. Vetere (PSU) report on behalf of the Swift Team:

At 10:09:07 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 090929B (trigger=371050).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 117.705, -0.632 which is 
   RA(J2000) = 07h 50m 49s
   Dec(J2000) = -00d 37' 55"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a complex structure
with most activity in multiple peaks from T-10 sec to T+50 s, and additional
peaks at T+150 sec, during the XRT observations.  The peak count rate
was ~7000 counts/sec (15-350 keV), at ~40 sec after the trigger. 

The XRT began observing the field at 10:10:31.3 UT, 84.1 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 117.7202, -0.6574 which is equivalent to:
   RA(J2000)  = 07h 50m 52.84s
   Dec(J2000) = -00d 39' 26.6"
with an uncertainty of 5.3 arcseconds (radius, 90% containment). This
location is 106 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. 

The initial flux in the 2.5 s image was 1.49e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of  97 seconds with the White
filter  starting 93 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  0.07.  We note there is a bright (10th mag) star less than
2 arcsec from the XRT position which complicates the analysis of the
UVOT data. 

Burst Advocate for this burst is C. Pagani (pagani 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: GRB090929A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9964
SUBJECT: GRB 090929: Enhanced Swift-XRT position
DATE:    09/09/29 14:00:14 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 2438 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 090929, 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 = 117.72015, -0.65764 which is equivalent
to:

RA (J2000): 07h 50m 52.84s
Dec (J2000): -00d 39' 27.5"

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, MNRAS, 397, 1177).

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


GRB_name: GRB090929B
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9965
SUBJECT: Correction: GRB 090929B: Enhanced Swift-XRT position
DATE:    09/09/29 14:09:34 GMT
FROM:    Kim Page at U.of Leicester  <kpa@star.le.ac.uk>

K.L. Page (U. Leicester) reports on behalf of the Swift-XRT team:

GCN Circ. 9964 referred to GRB 090929 when, in fact, the position given 
is for GRB 090929B (GCN Circ. 9963). The correct text should read

Using 2438 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 090929B, 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 = 117.72015, -0.65764 which is 
equivalent
to:

RA (J2000): 07h 50m 52.84s
Dec (J2000): -00d 39' 27.5"

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, MNRAS, 397, 1177).

We apologise for any confusion.


GRB_name: GRB090929A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9966
SUBJECT: GRB 090929A BAT location of the Fermi GBM burst
DATE:    09/09/29 14:15:48 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <jayc@milkyway.gsfc.nasa.gov>

J. R. Cummings (GSFC/UMBC) and H. Krimm (GSFC/USRA) on behalf of
the Swift team

The Fermi-GBM burst GRB 090929A (Rau, GCN Circular# 9962) occurred
during a preplanned Swift slew maneuver.  A strong source was found
in a mosaic of images from BAT event data, which is often collected
during slews.  The source location was RA, Dec = 56.494, -5.952 or

RA (J2000) 03h 45m 57.9s
Dec (J2000) -05d 57' 50"

with an estimated 90% containment error radius of 3 arcmin. The
partial coding was 73-90% during the burst.

We define the trigger time as 04:33:08 UTC.  As seen in BAT, the
burst had three progressively weaker peaks, at T+1, T+4, and T+8.
The peak count rate (15-350 keV) was ~18000 counts/sec at T+2 sec.
T90 was about 10 seconds.

A Swift TOO has been requested and approved.


GRB_name: GRB090929B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9967
SUBJECT: GRB 090929B: RAPTOR Discovery of Optical Counterpart
DATE:    09/09/29 16:46:34 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
371050 (Pagani et al., GCN 9963) under good observing conditions.
Our narrow-field instruments began observing the location at
10:20:53.37 UTC, 11.77 minutes after the initial BAT trigger.
Our initial images show an R~16.8 optical counterpart at the enhanced
XRT location (Page et al., GCN 9965).  The object fades steadily
reaching R~18.0 at 10:50 UTC.  Our unfiltered images were calibrated
against the USNO-B1 R-band. Unfortunately, an 11th magnitude star is
only 19 arcseconds away, limiting our photometric accuracy.  Further
analysis is ongoing.


GRB_name: GRB090929A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9968
SUBJECT: Konus-RF observation of GRB 090929A
DATE:    09/09/29 17:45:37 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, and D. Svinkin on behalf of
the Konus-RF team, report:

The bright GRB 090929A (Fermi-GBM trigger trigger 275891585:
Rau, GCN 9962) localized by Swift-BAT (Cummings and Krimm , GCN 9966)
triggered Konus-RF at T0=16384.747 s UT (04:33:04.747).

The burst light curve shows several multipeaked pulses with a total
duration of ~6 s.

As observed by Konus-RF the burst
had a fluence of 1.24(-0.11, +0.12)x10^-5 erg/cm2,
and a 16-ms peak flux measured from T0-0.040 s
of (2.02 +/- 0.46)x10^-5 erg/cm2/s
(both in the 20 keV - 3 MeV energy range).

The time-integrated spectrum of the burst (from T0-1.2 to T0+4.5 s)
is well fitted (in the 10 keV - 3 MeV range)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep), with
alpha = -0.55(-0.11, +0.12),  and
Ep = 480(-54, +64) keV (chi2 = 120.1/119 dof).
The spectrum accumulated over the burst maximum (from T0-0.2 to T0+0.1 
s) is well fitted (in the 10 keV - 3 MeV range)
by a power law with exponential cutoff model with
alpha = -0.28(-0.14, +0.15),  and
Ep = 633(-71, +81) keV (chi2 = 44.0/56 dof).
Fitting by GRB (Band) model yields the same alpha and Ep,
and only an upper limit on the high energy
photon index: beta < -3.06 (chi2 = 44.0/55 dof).

All the quoted values are preliminary.
All the quoted errors are at the 90% confidence level.

The Konus-RF light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB090929_T16384/KRF/


GRB_name: GRB090929B
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9969
SUBJECT: GRB 090929B: Swift/UVOT Observations
DATE:    09/09/29 19:13:57 GMT
FROM:    Peter Curran at MSSL  <pac@mssl.ucl.ac.uk>

P.A. Curran (MSSL-UCL), F. Marshall (GSFC), S. Holland (GSFC) and C.
Pagani (PSU) report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 090929B 94s 
after the BAT trigger (Pagani et al., GCN Circ. 9963). No optical 
afterglow is detected in the b, u or uvw2 UVOT exposures. There is a 
detection in the white filter, consistent with the enhanced XRT position 
(Goad et al. GCN 9964, Page et al. GCN 9965), the proposed optical 
counterpart (Wren et al. GCN 9967) and a USNO catalogued star (R2=19.3). 
Since the photometry is contaminated by a bright (R = 9.5), near-by star, 
we cannot determine the nature of the source at this time.


Preliminary magnitudes and 3-sigma upper limits using the UVOT photometric 
system (Poole et al. 2008, MNRAS, 383, 627) for the initial exposures are:

Filter       T_start(s)   T_stop(s)     Exp(s)      Mag
----------------------------------------------------------------
white        94           4032          292         18.7 +/- 0.5
b            3627         3827          197         >20.5
u            3422         3622          197         >20.3
uvw2         4038         4224          183         >20.3

The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.07 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB090929B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9970
SUBJECT: GRB 090929B: Skynet/DSO Observations
DATE:    09/09/29 20:28:10 GMT
FROM:    Josh Haislip at U.North Carolina  <haislip@physics.unc.edu>

J. Haislip, D. Reichart, A. Smith, D. Caton, L. Hawkins, K. Ivarsen, M. 
Schubel, A. LaCluyze, A. Foster, J. Moore, A. Oza, M. Schubel, J. Styblova, 
A. Trotter, J. A. Crain, and M. Nysewander report:

Skynet observed the Swift/BAT localization of GRB 090929B (Pagani et al., 
GCN 9963) with the 14" Dark Sky Observatory telescope in North Carolina 
beginning 12.0 minutes after the trigger in I.

We do not detect the afterglow (Pagani et al., GCN 9963, Wren et al., GCN 
9967) within the enhanced Swift/XRT localization (Goad et al., 9964; Page, 
GCN 9965).  However, the nearby I = 9.07 mag (USNO B1) star complicates 
photometry.

mean                                                     1-sig.   1-sig.
time                              3-sig.                 sys.     stat.
since                             lim.     cal.          cal.     cal.
trig.   tel.     exp.      fil.   mag.     stars         unc.     unc.
(h)              (# x s)                                 (mag)    (mag)

12.0    DSO-14   1 x 80    I      17.1     183 USNO B1   0.400    0.001


GRB_name: GRB090929B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9971
SUBJECT: GRB 090929B: Gemini-N upper limits
DATE:    09/09/29 21:12:50 GMT
FROM:    Antonino Cucchiara at PSU  <cucchiara@astro.psu.edu>

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

On September 29.58 UT we observed the field of GRB 090929B
(Pagani et al. GCN 9963) with Gemini-North + NIRI.
We took a sequence of YJHK bands images under twilight conditions.

No clear afterglow candidate has been found in the XRT refined error
circle (GCN 9964 and 9965) to the following limits (3-sigma):

J > 21.10 mag
H > 19.53 mag
K > 18.06 mag

Our limits are estimated using detected 2MASS objects at comparable
distance to the bright star (R = 9.5) which is located near the XRT
error circle.
We note the presence of a USNO catalogued star inside the refined
error circle; the above limits are exclusive of that star.

We thank the Gemini staff for performing these observations, in
particular Ricardo Schiavon.


GRB_name: GRB090926A
Detection_method: Fermi LAT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9972
SUBJECT: GRB 090926A: Fermi LAT and GBM refined analysis
DATE:    09/09/29 21:20:20 GMT
FROM:    Elisabetta Bissaldi at MPE  <ebs@mpe.mpg.de>

Elisabetta Bissaldi (MPE), Michael S. Briggs (UA Huntsville), 
Frederic Piron (IN2P3/LPTA), Hiromitsu Takahashi and 
Takeshi Uehara (Hiroshima University) 
report on behalf of the Fermi LAT and GBM teams:


Further analysis of GRB 090926A (Bissaldi GCN 9933, Uehara et al. GCN 99934,
Vetere et al. GCN 9336) reveals it is detected in the Fermi Large Area
Telescope (LAT) at least until 300 s after the Fermi Gamma-Ray Burst Monitor
(GBM) trigger time, T0=04:20:26.99 UT, with some indication for very
extended emission up to a few kilo-seconds.

Spectral analysis of the main emission episode, from T0 to T0+20.7 s, is
well-fit by a Band function with Epeak = 268 +/- 4 keV, 
alpha = -0.693 +/ 0.009 and beta = -2.342 +/- 0.011 
(C-STAT 1277 for 699 d.o.f.). Additionally, an effective area correction 
of 0.8 and 0.85 is applied to both BGO detectors with respect to the NaI
detectors and LAT.

The brightest interval, i.e. from T0+8.5 s to T0+10.5 s, includes a bright,
narrow spike that is present from ~10 keV to >100 MeV. It shows a deviation
from the Band function. The parameters for this multi-component fit 
(C-STAT = 781 for 697 d.o.f.) are Band_Epeak = 233 +/- 8, 
Band_alpha = -0.43 +/- 0.06, Band_beta = -3.00 +/- 0.13, 
and a power-law index of -1.845 +/- 0.019 for the additional component. 
In this case, the effective area correction applied to both BGOs is 0.76.

The fluence between 10 keV and 10 GeV is (2.47 +/- 0.03)E-04 erg/cm^2 
within the 21 seconds (the GBM T90) following the GBM trigger.

The points of contact for this burst are: 

Takeshi Uehara (uehara@hep01.hepl.hiroshima-u.ac.jp) and 
Elisabetta Bissaldi (ebs@mpe.mpg.de).


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: GRB090929B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9973
SUBJECT: GRB 090929B: Swift-XRT refined analysis
DATE:    09/09/30 01:40:54 GMT
FROM:    Claudio Pagani at PSU/Swift-XRT  <pagani@astro.psu.edu>

C. Pagani and L. Vetere (PSU) report on behalf of the Swift-XRT team:

We have analysed 3.7 ks of XRT data for GRB 090929B (Pagani et al. GCN Circ.
9963), from 90 s to 16.3 ks after the BAT trigger. The first orbit of data was
entirely taken in Windowed Timing (WT) mode for a total of 100 s.  The
remaining orbits are in Photon Counting (PC) mode. The enhanced XRT position
for this burst was given by Page (GCN. Circ 9965).

The light curve shows intense flaring activity during the first orbit with the
strongest emission at approximately 180 counts s^-1 at T+150 s, during a peak
also detected by the BAT (GCN Circ. 9963).  The following orbits can be modeled
with a broken power-law decay with an shallow phase of index of alpha=0.5 (+1.0,
-0.6) followed by a steeper decay of index alpha=1.2+/-0.3 after ~T+5.6 ks.

A spectrum formed from the WT mode data can be fitted with an absorbed power-law
with a photon spectral index of 1.68 (+/-0.05). The best-fitting absorption
column is 2.2 (+/-0.1) x 10^21 cm^-2, in excess of the Galactic value of 5.4 x
10^20 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index of
2.01 (+0.18, -0.17) and a best-fitting absorption column of 1.6 (+0.5, -0.4) x
10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 4.1 x 10^-11 (5.7 x 10^-11) erg cm^-2
count^-1.

If the light curve continues to decay with a power-law decay index of 1.2, the
count rate at T+24 hours will be 0.015 count s^-1, corresponding to an observed
(unabsorbed) 0.3-10 keV flux of 6.1 x 10^-12 (8.6 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/00371050.

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


GRB_name: GRB090927A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9974
SUBJECT: GRB 090927: Fermi GBM observation
DATE:    09/09/30 13:01:46 GMT
FROM:    David Gruber at MPE  <dgruber@mpe.mpg.de>

D. Gruber (MPE), E. Bissaldi (MPE) and S. McBreen (UCD/MPE)
report on behalf of the Fermi GBM Team:


"At 10:07:17.21 UT on 27 September 2009, the Fermi Gamma-Ray Burst  
Monitor
triggered and located GRB 090927 (trigger 275738839 / 090927422),
which was also detected by the Swift-BAT (Grupe al. 2009, GCN 9945).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 85 degrees.

The GBM light curve consists of one weak pulse with
a duration of about 2 seconds.
The time-averaged spectrum from T0-0.256 s to T0+0.896 s is
adequately fit by a simple power law function
with index -1.47 +/- 0.06 (C-stat 330 for 239 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(6.1 +/- 0.5)E-07 erg/cm^2. The 128-msec peak photon flux measured
starting from T0-0.128 s in the 8-1000 keV band
is 7.2 +/- 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: GRB090929B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9975
SUBJECT: Konus-Wind observation of GRB 090929B
DATE:    09/09/30 13:30:14 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 long GRB 090929B (Swift-BAT trigger #371050: Pagani et al., GCN 
9963) triggered Konus-Wind at T0=36565.377 s UT (10:09:25.377).

The burst light curve shows a multipeaked structure with a total
duration of ~20 s.

As observed by Konus-Wind the burst
had a fluence of (1.16 +/- 0.12)x10^-5 erg/cm2,
and a 256-ms peak flux measured from T0+16.208 s
of (3.80 +/- 0.90)x10^-6 erg/cm2/s
(both in the 20 keV - 1 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+16.640 s) is well fitted (in the 20 keV - 1 MeV
range) by GRB (Band) model for which:
the low-energy photon index alpha = -0.41 (-0.77, +1.16),
the high energy photon index beta = -1.82(-0.59, +0.24),
the peak energy Ep = 282(-78, +169) keV (chi2 = 52.4/59 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/GRB090929_T36565/


GRB_name: GRB090929A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9976
SUBJECT: Konus-Wind observation of GRB 090929A
DATE:    09/09/30 16:16:53 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 bright GRB 090929A (Fermi-GBM trigger trigger 275891585:
Rau, GCN 9962) localized by Swift-BAT (Cummings and Krimm, GCN 9966)
triggered Konus-Wind at T0=16387.790 s UT (04:33:07.790).

As observed by Konus-Wind the burst
had a fluence of 1.32(-0.24, +0.23)x10^-5 erg/cm2,
and a 16-ms peak flux measured from T0+0.736 s
of 2.04(-0.61, +0.60)x10^-5 erg/cm2/s
(both in the 20 keV - 3 MeV energy range).

The time-integrated spectrum of the burst (from T0 to T0+8.448 s)
is well fitted (in the 20 keV - 3 MeV range)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep), with
alpha = -0.47(-0.22, +0.25),  and
Ep = 574(-100, +151) keV (chi2 = 66.2/65 dof).
Fitting by GRB (Band) model yields:
the low-energy photon index alpha = -0.36(-0.29, +0.62),
the high energy photon index beta = -2.16(-1.41, +0.43),
the peak energy Ep = 494(-191, +175) keV (chi2 = 62.1/64 dof).

These values are consistent with the Konus-RF results (Golenetskii et 
al., GCN 9968).

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/GRB090929_T16384/


GRB_name: GRB090929A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9977
SUBJECT: GRB 090929A: Swift-XRT non-detection
DATE:    09/09/30 16:21:47 GMT
FROM:    Kim Page at U.of Leicester  <kpa@star.le.ac.uk>

K.L. Page (U. Leicester) reports on behalf of the Swift-XRT team:

Swift performed a short Target of Opportunity observation of GRB 090929A 
about 13 hours after the burst (Rau, GCN Circ. 9962; Cummings & Krimm, GCN 
Circ. 9966; Golenetskii et al., GCN Circ. 9968). This area of sky was a 
hot target for the XRT, so only a short observation was performed, with 
1.4 ks of data being collected in Photon Counting mode.

We do not detect a source within the BAT error circle, to a 90% upper 
limit of 0.015 count s^-1 over 0.3-10 keV. Assuming a typical counts to 
flux conversion of 3.8 x 10^-11 erg cm^-2 ct^-1 (Evans et al., 2009, 
MNRAS, 397, 1177), this corresponds to an observed flux of 5.7 x 10^-13 
erg cm^-2 s^-1. We note that this is not a very constraining upper limit, 
because of the greater than usual background caused by the high XRT CCD 
temperature and the short exposure time.

Filtering out all photons below 1 keV, a more stringent upper limit of 9 x 
10^-3 count s^-1 (1-10 keV; observed flux of ~3.4 x 10^-13 erg cm^-2 s^-1) 
can be determined.

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


GRB_name: GRB090929B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9979
SUBJECT: GRB 090929B, Swift-BAT refined analysis
DATE:    09/09/30 21:04:27 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),
C. Pagani (PSU),
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-239 to T+691 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 090929 (trigger
#371050) (Pagani, et al., GCN Circ. 9963).  The BAT ground-calculated
position is RA, Dec = 117.712, -0.645 deg which is
    RA(J2000)  =  07h 50m 50.9s
    Dec(J2000) = -00d 38' 41.2"
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 63%.

The mask-weighted lightcurve shows many peaks interspersed with
intervals with no detected flux, from T-10 to T+380 sec when the source
left the coded field of view due to a observing constraint. There may
have been small and/or low-energy peaks beyond this time.  The largest
peak was at about T+30 to T+40 sec. T90 (15-350 keV) was 360 +- 20 sec
(estimated error including systematics).

The time-averaged spectrum from T-9.8 to T+371.0 sec is best fit by a
simple power-law model.  The power law index of the time-averaged
spectrum is 1.85 +- 0.08.  The fluence in the 15-150 keV band is
5.9 +- 0.3 x 10^-06 erg/cm2.  The 1-sec peak photon flux measured from
T+30.67 sec in the 15-150 keV band is 3.3 +- 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/371050/BA/


GRB_name: GRB090929A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9980
SUBJECT: GRB 090929A, Swift-BAT refined analysis
DATE:    09/09/30 21:06:52 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),
K. Page (U Leicester),
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):

We report further analysis of Fermi-GBM GRB 090929A (Rau, et al.,
GCN Circ. 9962).  The BAT ground-calculated position is the same
as stated in Cummings et al. (GCN Circ. 9966),
RA, Dec = 56.494, -5.952 or

RA (J2000) 03h 45m 57.9s
Dec (J2000) -05d 57' 50"

with an estimated 90% containment error radius of 3 arcmin. The
partial coding was 73-90% during the burst.

The mask-weighted lightcurve shows multiple peaks and spikes, at
T+1, T+2, T+4, T+5, and T+10 sec, where T0 is 04:33:07. T90 was
7 +- 2 seconds.

The time-averaged spectrum from T0 to T+12 sec is best fit by a
simple power-law model.  The power law index of the time-averaged
spectrum is 0.96 +- 0.04.  The fluence in the 15-150 keV band is
1.69 +- 0.07 x 10^-06 ergs/cm2.  The 1-sec peak photon flux
measured from T+0.5 sec in the 15-150 keV band is
5.9 +- 0.3 ph/cm2/sec. All the quoted errors are at the 90%
confidence level.


GRB_name: GRB090929A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9981
SUBJECT: GRB 090929A: Swift/UVOT Observations
DATE:    09/09/30 22:34:16 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@astro.psu.edu>

M. H. Siegel (PSU) and K. L. Page (U. Leicester) report on behalf
of the Swift/UVOT team.

Swift/UVOT began settled observations of GRB 090929A about 13 hours  
after
the burst (Rau, GCN Circ. 9962; Cummings & Krimm, GCN Circ. 9966;
Golenetskii et al., GCN Circ. 9968; Page, GCN Circ 9977).  Due to the
presence of a 9th magnitude (V) star 45" from the center of the BAT  
position,
data were only obtained in the UVM2 filter.

We do not detect any uncatalogued UV source within the BAT error circle.
The 3-sigma upper limit and summed exposure is reported below:

FILTER     T_start(s)  T_stop    Exposure     Mag/3UL
=============================================================
UVM2         47411      52924      2252            >21.26
=============================================================

This magnitude is not corrected for the Galactic extinction  
corresponding
to a reddening of E_{B-V} = 0.07 (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: GRB090926A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9982
SUBJECT: GRB 090926A: Skynet/PROMPT Observations of Post-Peak Fading
DATE:    09/10/01 04:36:16 GMT
FROM:    Josh Haislip at U.North Carolina  <haislip@physics.unc.edu>

J. Haislip, D. Reichart, K. Ivarsen, A. LaCluyze, A. Foster, J. Moore, A. 
Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. Nysewander 
report:

Skynet has continued to observe the afterglow (Haislip et al., GCN 9937) of 
GRB 090926A (Bissaldi, GCN 9933) with four of the 16" PROMPT telescopes at 
CTIO in BVRI.

Since peaking in brightness approximately 1 day after the trigger (Haislip 
et al., GCN 9953), the afterglow has been fading with a power-law index of 
approximately -1.4.

At 4.1 days after the trigger, it's magnitude is R = 20.09 +0.10 -0.09 
(statistical)  0.57 (systematic; calibrated to 172 USNO B1 stars).

Skynet's most recent BVRI light curve, calibrated to USNO B1 and NOMAD 
stars, can be found here:

http://skynet.unc.edu/grb/grb090926a.jpg


GRB_name: GRB091003A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9983
SUBJECT: GRB 091003A: Fermi GBM detection
DATE:    09/10/03 11:42:08 GMT
FROM:    Arne Rau at MPE  <arau@mpe.mpg.de>

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

"At 04:35:45.58 UT on 03 September 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 091003A (trigger 276237347 / 091003191).

The on-ground calculated location, using the GBM trigger
data, is RA = 251.1, DEC = 37.2 (J2000 degrees,
equivalent to 16h 44m, 37d 12'), with an uncertainty
of 1.0 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 13 degrees.

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

The GBM light curve consists of multiple peaks
with a duration (T90) of about 21.1 +/- 0.5s (8-1000 keV).
The time-averaged spectrum from T0-0.384s to T0+23.168s is
best fit by a Band function with Epeak = 486.2 +/- 23.6 keV,
alpha = -1.13 +/- 0.01, and beta = -2.64 +/- 0.24
(chi squared 851 for 611 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(3.76 +/- 0.04)E-05 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+18.048 s in the 8-1000 keV band
is 31.8 +/- 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: GRB090926A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9984
SUBJECT: GRB 090926A: Skynet/PROMPT Observations of Day 4 - 6 Fading Rate
DATE:    09/10/03 20:49:13 GMT
FROM:    Josh Haislip at U.North Carolina  <haislip@physics.unc.edu>

J. Haislip, D. Reichart, K. Ivarsen, A. LaCluyze, A. Foster, J. Moore, A. 
Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. Nysewander 
report:

Skynet has continued to observe the afterglow (Haislip et al., GCN 9937) of 
GRB 090926A (Bissaldi, GCN 9933) with four of the 16" PROMPT telescopes at 
CTIO in BVRI.

After peaking in brightness approximately 1 day after the trigger (Haislip 
et al., GCN 9953), the afterglow had been fading with a power-law index of 
approximately -1.4 until approximately 4 days after the trigger (Haislip, 
et al., GCN 9982).

Between 4 and 6 days after the trigger, the afterglow has been fading with 
a shallower power-law index of approximately -0.8.

At 6.1 days after the trigger, its magnitude is R = 20.40 +0.11 -0.10 
(statistical) +/-  0.57 (systematic; calibrated to 172 USNO B1 stars).

Skynet's most recent BVRI light curve, calibrated to USNO B1 and NOMAD 
stars, can be found here:

http://skynet.unc.edu/grb/grb090926a.jpg


GRB_name: GRB091003A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9985
SUBJECT: GRB 091003A: Fermi LAT detection
DATE:    09/10/03 21:46:38 GMT
FROM:    Julie McEnery at UMBC/GSFC  <mcenery@milkyway.gsfc.nasa.gov>

Julie McEnery (NASA/GSFC), Jim Chiang (SLAC) and Yoshitaka Hanabata  (Hiroshima) report on behalf of the Fermi LAT team:

At 04:35:45 (UT) on 03 Oct 2009, the Fermi Large Area Telescope (LAT) detected gamma rays from the long GRB 091003, which was triggered and located by the Fermi Gamma-ray Burst Monitor (GBM) (trigger 2756237347 / 091003191, GCN9983). The angle of the GBM best position (RA, Dec= 251.1, 37.2) with respect to the LAT boresight was ~13 degrees at the time of the trigger, which is close to the center of our field of view.

This burst was bright enough to initiate a Fermi spacecraft repointing maneuver resulting in 5 hours of pointed observations of the burst  position following the GBM trigger.

The data from the Fermi LAT shows a significant increase in the event rate after the GBM trigger that is spatially and temporally correlated with the GBM emission with high significance (>10 sigma).

The best LAT on-ground localization is found to be (RA, Dec = 251.39, 36.58) with a 90% containment radius of 0.21 deg (statistical; 68% containment radius: 0.15 deg, preliminary systematic error is less than 0.1 deg) which is consistent with the GBM localization.

A Swift TOO request has been issued.

Further analysis is ongoing.

The point of contact for this burst is

Julie McEnery : julie.mcenery@nasa.gov

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: GRB091003A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9986
SUBJECT: GRB 091003: Swift XRT analysis 
DATE:    09/10/04 00:44:01 GMT
FROM:    Rhaana Starling at U of Leicester  <rlcs1@star.le.ac.uk>

R.L.C. Starling and A.P. Beardmore (U. Leicester) report on behalf
of the Swift-XRT team:

The Swift X-ray Telescope (XRT) observed the Fermi GBM/LAT and
Integral-detected GRB 091003 (Rau GCN Circ. 9983; McEnery et al. GCN
Circ. 9985) on 2009 October 3 at 20:07:28 UT, 15.5 hours after the
Fermi trigger.

In 2.5 ks of photon counting mode data we detect an uncatalogued
X-ray source at  RA, Dec = 251.52047, 36.62548 degrees, which is
equivalent to:

RA (J2000) = 16:46:04.9
Dec (J2000) = +36:37:31.74

with an uncertainty of 3.7 arcsec (radius, 90% containment). This
is 6.85 arcmin from the Fermi LAT position and within its error circle.

A spectrum formed from these data can be fit with an absorbed power law of
photon index 1.7+/-0.3, with nH < 2e21 cm-2, and has an observed 0.3-10 keV 
count rate of 0.087+/-0.007 count/s corresponding to a flux of 3.6e-12 
erg/cm2/s.

At this stage we do not have enough data to tell if the source is fading.

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


GRB_name: GRB091003A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9987
SUBJECT: GRB 091003: Swift UVOT Detection of a Candidate UV Afterglow
DATE:    09/10/04 02:21:18 GMT
FROM:    Caryl Gronwall at PSU/Swift-UVOT  <caryl@astro.psu.edu>

C. Gronwall (PSU) and R.L.C. Starling (U. Leicester) report on behalf
of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 091003
approximately 15.5 hours after the Fermi/GBM trigger (Rau,
GCN Circ. 9983).  In a 885 sec observation in the uvw2 filter, we
find a faint candidate fading UV afterglow within the XRT error circle
(Starling & Beardmore, GCN Circ. 9986).  The estimated magnitude is
21.02 +/- 0.27.  This value is 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: GRB091003A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9988
SUBJECT: GRB 091003: UVOT-enhanced XRT position
DATE:    09/10/04 12:10:23 GMT
FROM:    Rhaana Starling at U of Leicester  <rlcs1@star.le.ac.uk>

R.L.C. Starling, P.A. Evans, A.P. Beardmore and M.R. Goad (U. Leicester) 
report on behalf of the Swift-XRT team:

Using 4881 s of XRT Photon Counting mode data and 11 UVOT 
images for GRB 091003, 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 =
251.51980, 36.62470 which is equivalent to:

RA (J2000):  16 46 4.75
Dec (J2000): +36 37 29.0

with an uncertainty of 1.7 arcsec (radius, 90% confidence). The UV 
counterpart reported in Gronwall & Starling (GCN Circ.9987) is consistent 
with this position.

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, MNRAS, 397, 1177).

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


GRB_name: GRB091003A
Detection_method: Fermi LAT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9989
SUBJECT: GRB 091003: Skynet/DSO Observations
DATE:    09/10/04 18:14:15 GMT
FROM:    Josh Haislip at U.North Carolina  <haislip@physics.unc.edu>

J. Haislip, D. Reichart, A. Smith, D. Caton, L. Hawkins, K. Ivarsen, A. 
LaCluyze, A. Foster, J. Moore, A. Oza, M. Schubel, J. Styblova, A. Trotter, 
J. A. Crain, and M. Nysewander report:

Skynet observed the Fermi/LAT localization (McEnery, Chiang & Hanabata, GCN 
9985) of GRB 091003 (Rau, GCN 9935) with the 14" Dark Sky Observatory 
telescope in North Carolina beginning 20.2 hours after the trigger in BVRI.

We do not detect the afterglow (Starling & Beardmore, GCN 9986; Gronwall & 
Starling, GCN 9987).  Stacking only images that increase the limiting 
magnitude yields:

mean                                             1-sig.  1-sig.
time                          3-sig.             sys.    stat.
since                         lim.    cal.       cal.    cal.
trig.  tel.    exp.     fil.  mag.    stars*     unc.    unc.
(h)            (# x s)                           (mag)   (mag)

21.0   DSO-14  16 x 80  V     19.6    58 SDSS 7  0.076   0.000
21.0   DSO-14  17 x 80  B     19.5    33 SDSS 7  0.087   0.001
21.0   DSO-14  16 x 80  R     19.8    64 SDSS 7  0.064   0.000
21.0   DSO-14  16 x 80  I     19.3    45 SDSS 7  0.049   0.000

* Transformed using Jester et al., 2005, ApJ, 130, 873.


GRB_name: GRB091003A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9990
SUBJECT: GRB 091003: Swift/UVOT Detection of an Optical Afterglow
DATE:    09/10/04 23:42:48 GMT
FROM:    Tyler Pritchard at PSU  <tapritchard@astro.psu.edu>

T. A. Pritchard (PSU) , E.A. Hoversten (PSU), and
R.L.C. Starling (U. Leicester) report on behalf of the
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of
GRB 091003 approximately 15.5 hours after the FERMI/GBM Trigger (Rau,
GCN Circ. 9983) A faint source is detected with 3.9-sigma confidence
in the summed UVOT observations at the Swift UVOT-enhanced XRT
position (R.L.C. Starling, et al. GCN Circ. 9988).

The observed magnitudes and upper limits using the UVOT photometric
system (Poole etal. 2008, MNRAS, 383, 627) for the initial exposures
are:

Filter   T_start(s)   T_stop(s)   Exp(s)          Mag
=======================================================================
w2        56820        64169    1150     21.08  0.28 (3.9 sigma)
w1       103712       104474     750     20.70  0.32 (3.4 sigma)
b         92252        92954     685     20.80  0.26 (4.1 sigma)

m2   98013        98715     691     > 21.63
v         86432        87195     741     > 20.27

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: GRB091003A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9991
SUBJECT: GRB 091003: Swift-XRT confirmation of fading afterglow
DATE:    09/10/05 07:59:40 GMT
FROM:    Kim Page at U.of Leicester  <kpa@star.le.ac.uk>

K.L. Page, R.L.C. Starling, P.A. Evans & A.P. Beardmore (U. Leicester) 
report on behalf of the Swift-XRT team:

We have now collected 15 ks of Swift-XRT Photon Counting mode data on the 
Fermi burst GRB 091003 (Rau, GCN Circ. 9983; McEnery, Chiang & Hanabata, 
GCN Circ. 9985), between 56 and 168 ks after the trigger. The light-curve 
is fading, with alpha = 1.02 +0.21/-0.20. We therefore confirm that the 
source given by Starling et al. in GCN Circ. 9986 and 9988 is, indeed, the 
X-ray afterglow.

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


GRB_name: GRB090929A
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9992
SUBJECT: GRB 090929A: Suzaku WAM observation of the prompt emission
DATE:    09/10/05 08:59:49 GMT
FROM:    Norisuke Ohmori at Miyazaki U  <ohmori@astro.miyazaki-u.ac.jp>

N. Ohmori, E. Sonoda, K. Kono, H. Hayashi, A. Daikyuji, 
Y. Nishioka, K. Noda, 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 090929A (Fermi-GBM trigger 275891585  / 090929190;
Arne Rau et al., GCN9962) triggered the Suzaku Wide-band All-sky 
Monitor (WAM) which covers an energy range of 50 keV - 5 MeV
at 04:33:04.634 UT (=T0).

The observed light curve shows a bright multi-peaked structure
starting at T0-1 s, ending at T0+5 s. 
The total T90 duration is about 3.8 seconds.

The fluence in 100 - 1000 keV was 4.96 (-4.47, +5.32) x10-6 erg/cm2.
The 1-s peak flux measured from T0-0.5s was 5.59 (-0.68, +0.53)
photons/cm2/s in the same energy range.
The incident angle for this burst is not good, so the fluence 
and peak flux might have large systematic uncertainties.

Preliminary result shows that the time-averaged spectrum from
T0-1s to T0+5s is well fitted by a power-law with exponential cutoff model:
  dN/dE ~  E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
  alpha       0.86(-0.80, +0.36), and
  Epeak        557(-98, +117) keV (chi2/d.o.f. = 125/98).

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: GRB090929B
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9993
SUBJECT: GRB 090929B: Suzaku WAM observation of the prompt emission
DATE:    09/10/05 09:02:34 GMT
FROM:    Norisuke Ohmori at Miyazaki U  <ohmori@astro.miyazaki-u.ac.jp>

N. Ohmori, E. Sonoda, K. Kono, H. Hayashi, A. Daikyuji, 
Y. Nishioka, K. Noda, M. Yamauchi (Univ. of Miyazaki),
K. Yamaoka (Aoyama Gakuin U.), 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), 
Y. E. Nakagawa, T. Tamagawa (RIKEN), S. Hong (Nihon U.), 
S. Sugita (Nagoya U.), N. Vasquez (Tokyo Tech.),
on behalf of the Suzaku WAM team, report:

The long GRB 090929B (Swift-BAT trigger #371050; Pagani et al., GCN 9963, 
 Krimm et al. GCN 9979) was detected by the Suzaku Wide-band All-sky 
Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 
10:09:23.633 UT (=T0).

The observed light curve shows a multi-peaked structure, starting at
T0-2 s and ending at T0+20 s, with a total duration (T90) of about 18 s.
The fluence in 100 - 1000 keV was (3.92 $B!^(B 0.63) x 10-6 erg/cm2.
The 1-s peak flux measured from T0+1 s was 1.42 (-0.25. +0.24)
photons/cm2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from
T0-2 s to T0+20 s is well fitted by a single power-law with 
 a photon index of 1.96 (-0.17, +0.20) (chi2/d.o.f = 23.4/27).
 
All the quoted errors are at statistical 90% confidence level,
in which the systematic uncertainties are not included.

The light curves for this burst will be available at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html


GRB_name: GRB091003A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9994
SUBJECT: Konus-Wind observation of GRB 091003A
DATE:    09/10/05 10:14:24 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 long bright GRB 091003A (Fermi-GBM trigger 276237347 / 091003191:
Rau, GCN 9983) localized by Fermi-LAT (McEnery et al., GCN 9985)
triggered Konus-Wind at T0=16543.801 s UT (04:35:43.801).

The burst light curve shows a multipeaked structure with a total
duration of ~23 s.

As observed by Konus-Wind the burst
had a fluence of 3.44(-0.19, +0.20)x10^-5 erg/cm2,
and a 16-ms peak flux measured from T0+18.592 s
of (1.68 +/- 0.32)x10^-5 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+26.880 s) is well fitted (in the 20 keV - 2 MeV
range) by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep), with
alpha = -1.04 +/- 0.06,  and
Ep = 381(-36, +44) keV (chi2 = 58.4/61 dof).
Fitting by GRB (Band) model yields the same alpha and Ep,
and only an upper limit on the high energy
photon index: beta < -2.22 (chi2 = 56.2/60 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/GRB091003_T16543/


GRB_name: GRB091003A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9995
SUBJECT: GRB 091003: WHT ACAM observations
DATE:    09/10/05 17:11:44 GMT
FROM:    Klaas Wiersema at U of Leicester  <kw113@star.le.ac.uk>

K. Wiersema, N. Tanvir (Leicester), A. Levan (Warwick) and C. Benn (ING) 
report on behalf of a larger collaboration:

We observed the afterglow of Fermi GRB 091003 (Rau GCN 9983; McEnery et al 
GCN 9985; Starling & Beardmore GCN 9986) with the William Herschel 
Telescope, using the ACAM instrument. We took a 60 and a 250 second 
exposure in imaging mode, starting at 21:11 UT, October 4 (1.69 days after 
burst).
The afterglow is clearly detected, with r = 21.33 +/- 0.11 (calibrated to 
SDSS field stars), at position:

RA (J2000) = 16:46:04.687
Dec (J2000) = +36:37:30.76
with uncertainty 0.3 arcseconds.

We obtained spectroscopy with ACAM immediately after, at high airmass. Two 
900 second exposures were obtained using the 400V grism and a 1 arcsecond 
slit. Faint continuum emission is detected over the 4000-9300 A range. No 
strong absorption or emission lines are detected. The detection of 
continuum at 4000A gives a upper limit to the redshift of 2.3.


GRB_name: GRB090926B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9996
SUBJECT: GRB 090926B: Skynet/PROMPT Observations
DATE:    09/10/06 04:07:49 GMT
FROM:    Josh Haislip at U.North Carolina  <haislip@physics.unc.edu>

J. Haislip, D. Reichart, K. Ivarsen, A. LaCluyze, A. Foster, J. Moore, A. 
Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. Nysewander 
report:

Skynet observed the Swift/BAT localization of GRB 090926B (Grupe et al., 
GCN 9935) with four of the 16" PROMPT telescopes at CTIO beginning 2.7 
hours after the trigger in UVRI.

We do not detect the afterglow (Grupe et al., GCN 9935; Malesani, Fynbo & 
D'Elia, GCN 9944).  Stacking only images that increase the limiting 
magnitude yields:

mean                                                1-sig.  1-sig.
time                            3-sig.              sys.    stat.
since                           lim.    cal.        cal.    cal.
trig.  tel.      exp.     fil.  mag.    stars       unc.    unc.
(h)              (# x s)                            (mag)   (mag)

2.7    PROMPT-4  4 x 80   R     19.9    40 USNO B1  0.424   0.002
2.7    PROMPT-2  4 x 80   V     18.2    11 NOMAD    0.099   0.003
2.7    PROMPT-5  3 x 80   I     18.2    32 USNO B1  0.414   0.003


GRB_name: GRB091003A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9997
SUBJECT: GRB 091003: Lick observations and possible SDSS host galaxy
DATE:    09/10/06 22:17:22 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>

D. A. Perley, J. Choi, A. J. L. Morton, and M. Ganeshalingam (UC 
Berkeley) report:

We observed the position of Fermi GRB 091003 (Rau et al., GCN9983) using 
the Nickel 1m telescope at Lick Observatory on the night of 2009-10-06 
(UT) starting at 04:06 for a series of five 600-second exposures in 
R-band.  The afterglow (Starling and Beardmore, GCN 9986; Gronwall and 
Starling, GCN 9987) is marginally detected in the combined frame.

Calibrating to nearby SDSS stars transformed to R-band using the 
equations of Lupton et al. (2005) we estimate a magnitude of

R = 21.2 +/- 0.4  (t_mid = 3.00 days)

This suggests only limited fading since the observations of Wiersama et 
al. (GCN 9995).

Further, we note that a source coincident with this position is detected 
in the SDSS survey imaging.  The object (SDSS J164604.70+363731.1) has a 
magnitude of r = 23.2 and is classified as a star, but could represent 
the host galaxy of this event.  A low redshift would also be consistent 
with the absence of absorption signatures in the spectrum of Wiersema et 
al. and with the Swift UVW2 detection (Pritchard et al., GCN 9990).  We 
encourage further observations, in particular additional spectroscopy, 
of this object.


GRB_name: GRB091003A
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9998
SUBJECT: GRB 091003A: Suzaku WAM observation of the prompt emission
DATE:    09/10/07 02:43:10 GMT
FROM:    Kenta Kono at Miyazaki U  <kenta0514@astro.miyazaki-u.ac.jp>

K. Kono, E. Sonoda, N. Ohmori, K. Noda, H. Hayashi,
A. Daikyuji, Y. Nishioka, M. Yamauchi (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 091003A
(Fermi-GBM trigger 276237347 / 091003191 ; A. Rau et al., GCN 9983 ; J.
McEnery et al., GCN 9985)
triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an
energy range of 50 keV - 5 MeV at 04:35:45.586 UT (=T0).

The observed light curve shows a multi-peaked structure
starting at T0-2 s and ending at T0+23 s, with a total duration (T90) of
about 21 s.

The fluence in 100 - 1000 keV was 1.98(-0.14, +0.08)x10-5 erg/cm2.
The 1-s peak flux measured from T0+18 s was 7.53(-1.28, +0.39)
photons/cm2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from
T0-2 s to T0+23 s is well fitted by a power-law with exponential cutoff
model:
dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
alpha 1.19(-0.36, +0.29), and
Epeak 576(-72, +106) keV (chi2/d.o.f. = 21.5/24).

Due to the brightness of this burst, a 3% systematic error
was added for low energy channels.
All the quoted errors are at 90% confidence level,

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: GRB090812A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  9999
SUBJECT: GRB 090812: Skynet/PROMPT and GORT Observations
DATE:    09/10/08 04:54:57 GMT
FROM:    Josh Haislip at U.North Carolina  <haislip@physics.unc.edu>

J. Haislip, D. Reichart, K. Ivarsen, L. Cominsky, K. McLin, T. Graves, G. 
Spear, A. LaCluyze, A. Foster, J. Moore, A. Oza, M. Schubel, J. Styblova, 
A. Trotter, J. A. Crain, and M. Nysewander report:

Skynet observed the Swift/BAT localization of GRB 090812 (Stamatikos et 
al., GCN 9768) with four of the 16" PROMPT telescopes at CTIO beginning 3.9 
minutes after the trigger in UBVRI through variable cloud cover.

Skynet continued observing with the 14" GORT telescope at Hume Observatory 
in California beginning 48.4 minutes after the the trigger in RI.

We detect the afterglow (Stamatikos et al., GCN 9768).  Stacking only 
images that increase the limiting magnitude yields:

mean                                                       1-sig. 1-sig.
time                                                       sys.   stat.
since                                            cal.      cal.   cal.
trig.   tel.     exp.     fil. magnitude         stars*    unc.   unc.
                  (# x s)                                   (mag)  (mag)

15.0 m  PROMPT-4 2 x 80   R    > 17.7 (3 sig.)   50 SDSS 7 0.008  0.010
15.0 m  PROMPT-5 2 x 80   I    > 17.0 (3 sig.)   20 SDSS 7 0.026  0.010
15.0 m  PROMPT-2 2 x 80   V    > 17.4 (3 sig.)   15 SDSS 7 0.030  0.020
32.1 m  PROMPT-3 2 x 80   B    > 18.5 (3 sig.)   25 SDSS 7 0.028  0.031
32.6 m  PROMPT-2 4 x 80   V    > 18.3 (3 sig.)   15 SDSS 7 0.039  0.010
                  + 1 x 40
32.7 m  PROMPT-4 5 x 80   R    > 18.4 (3 sig.)   50 SDSS 7 0.008  0.005
32.7 m  PROMPT-5 5 x 80   I    > 17.8 (3 sig.)   20 SDSS 7 0.026  0.005
62.0 m  GORT     6 x 80   R    > 18.8 (3 sig.)   34 SDSS 7 0.039  0.003
76.8 m  GORT     9 x 80   I    > 18.7 (3 sig.)   43 SDSS 7 0.097  0.003
117.3 m PROMPT-2 8 x 80   V    > 18.7 (3 sig.)   17 SDSS 7 0.019  0.006
119.1 m PROMPT-4 11 x 80  R    > 19.1 (3 sig.)   62 SDSS 7 0.229  0.003
119.2 m PROMPT-5 11 x 80  I    > 18.4 (3 sig.)   25 SDSS 7 0.117  0.003
120.0 m PROMPT-3 10 x 80  B    > 19.4 (3 sig.)   26 SDSS 7 0.085  0.011
3.2 h   PROMPT-3 24 x 80  B    > 21.3 (3 sig.)   26 SDSS 7 0.085  0.003
3.2 h   GORT     16 x 80  I    > 19.2 (3 sig.)   43 SDSS 7 0.097  0.002
3.4 h   GORT     20 x 80  R    > 20.0 (3 sig.)   34 SDSS 7 0.039  0.001
3.5 h   PROMPT-2 67 x 80  V    21.05 +0.35 -0.27 17 SDSS 7 0.019  0.001
3.5 h   PROMPT-5 66 x 80  I    20.60 +0.26 -0.21 25 SDSS 7 0.117  0.001
3.5 h   PROMPT-4 65 x 80  R    21.35 +0.28 -0.22 62 SDSS 7 0.229  0.001
3.6 h   PROMPT-3 37 x 80  U    > 19.5 (3 sig.)   30 SDSS 7 0.015  0.012

* Transformed using Jester et al., 2005, ApJ, 130, 873.


GRB_name: GRB090904A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10000
SUBJECT: GRB 090904A: afterglow confirmation
DATE:    09/10/08 05:16:08 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@astro.ku.dk>

Daniele Malesani (DARK/NBI), Pall Jakobsson (Univ. Iceland), and Ilya 
Ilyin (AIP), report on behalf of a larger collaboration:

We observed again the field of GRB 090904A (Perri et al., GCN 9879) with 
the NOT equipped with StanCam. Observations were carried out in the R 
band, for a total exposure time of 30 min, with a mean time September 
6.218 UT (2.176 days after the GRB trigger).

The object identified in our previous epoch of imaging (Malesani et al., 
GCN 9884) has clearly faded and is hardly detectable, if at all. A faint 
source is visible at its position, with magnitude R = 24.0 +- 0.3. If 
real, the inferred decay slope is alpha = 0.55 +- 0.12, assuming F(t) 
propto t^-alpha. The value of alpha is shallower than usually found at 
late times, and may indicate some host contribution or an unusual light 
curve.

The position of the transient is consistent with the latest available 
UVOT-enhanced XRT position (Goad et al., GCN 9885; see also 
http://www.swift.ac.uk/xrt_positions/index.php). We thus identify the 
object as the optical afterglow of GRB 090904A.

A finding chart comparing the two epochs can be found at the following URL:

http://www.astro.ku.dk/~malesani/GRB/090904A/GRB090904A_finder_NOT.jpg


GRB_name: GRB090621A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10001
SUBJECT: Short-Duration GRB 090621: Skynet/Dolomiti Observations
DATE:    09/10/08 15:11:31 GMT
FROM:    Josh Haislip at U.North Carolina  <haislip@physics.unc.edu>

J. Haislip, D. Reichart, M. Maturi, K. Ivarsen, A. LaCluyze, A. Foster, J. 
Moore, A. Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. 
Nysewander report:

Skynet observed the Swift/BAT localization of short-duration GRB 090621 
(Curran et al., GCN 9545) with the 16" telescope at the Dolomiti 
Astronomical Observatory in Italy beginning 26.2 minutes after the trigger 
in Red, which we have calibrated to R.

We do not detect the afterglow (Curran et al., GCN 9545).  Stacking only 
images that increase the limiting magnitude yields:

mean                                                 1-sig.  1-sig.
time                           3-sig.                sys.    stat.
since                          lim.    cal.          cal.    cal.
trig.  tel.    exp.      fil.  mag.    stars         unc.    unc.
(m)            (# x s)                               (mag)   (mag)

35.3   DAO-16  4 x 160   R     19.9    1518 USNO B1  0.277   0.000
                + 3 x 80


GRB_name: GRB090518A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10002
SUBJECT: GRB 090518: Skynet/PROMPT Observations
DATE:    09/10/09 03:19:09 GMT
FROM:    Josh Haislip at U.North Carolina  <haislip@physics.unc.edu>

J. Haislip, D. Reichart, K. Ivarsen, A. LaCluyze, A. Foster, J. Moore, A. 
Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. Nysewander 
report:

Skynet observed the Swift/BAT localization of GRB 090518 (Evans et al., GCN 
9386) with four of the 16" PROMPT telescopes at CTIO beginning 3.3 minutes 
after the trigger in UVRI.

We do not detect the afterglow (Evans et al., GCN 9386) within the enhanced 
Swift/XRT localization (Evans et al., GCN 9387).  Stacking only images that 
increase the limiting magnitude yields:

mean                                                  1-sig.  1-sig.
time                             3-sig.               sys.    stat.
since                            lim.    cal.         cal.    cal.
trig.  tel.      exp.      fil.  mag.    stars        unc.    unc.
(m)              (# x s)                              (mag)   (mag)

5.2    PROMPT-4  4 x 40    I    18.2     229 USNO B1  0.372   0.001
                  + 1 x 10
5.8    PROMPT-5  2 x 40    V    18.3     72 NOMAD     0.146   0.001
6.4    PROMPT-2  1 x 80    R    19.3     217 USNO B1  0.305   0.001
                  + 2 x 40


GRB_name: GRB090926A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10003
SUBJECT: GRB 090926A: Skynet/PROMPT Observations of Day 6 - 11 Fading
DATE:    09/10/09 17:24:40 GMT
FROM:    Josh Haislip at U.North Carolina  <haislip@physics.unc.edu>

J. Haislip, D. Reichart, K. Ivarsen, A. LaCluyze, A. Foster, J. Moore, A. 
Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. Nysewander 
report:

Skynet has continued to observe the afterglow (Haislip et al., GCN 9937) of 
GRB 090926A (Bissaldi, GCN 9933) with two of the 16" PROMPT telescopes at 
CTIO in RI.

After peaking in brightness approximately 1 day after the trigger (Haislip 
et al., GCN 9953) and fading with a power-law index of around -1.4 until 
approximately 4 days after the trigger (Haislip, et al., GCN 9982), the 
afterglow faded with a shallower power-law index of around -0.8 until 
approximately 6 days after the trigger (Haislip et al., GCN 9984).

Between 6 and 11 days after the trigger, the afterglow has been fading with 
a steeper power-law index of around -1.7.

At 11.1 days after the trigger, its magnitude is R = 21.45 +0.22 -0.18 
(statistical) +/- 0.57 (systematic; calibrated to 172 USNO B1 stars).

Skynet's most recent BVRI light curve, calibrated to USNO B1 and NOMAD 
stars, can be found here:

http://skynet.unc.edu/grb/grb090926a.jpg

Continued observations with larger telescopes are encouraged.


GRB_name: GRB090910A
Detection_method: superAGILE
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10004
SUBJECT: GRB 090910: SuperAGILE Localization of a Long GRB
DATE:    09/10/10 05:24:39 GMT
FROM:    Marco Feroci at IASF/INAF  <sa.grb@iasf-roma.inaf.it>

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

"SuperAGILE detected a long gamma ray burst on 10 October 2009,
at 02:43:09 UT. The event had a duration of about 10 s in the 17-60 keV
energy range, with a highly structured shape. Assuming a Crab-like energy
spectrum, the peak flux on 1-s timescale was about 6.2E-07 erg/cm2/s.
The burst position was reconstructed  as (RA, Dec)
(298.669, -22.538) deg, which is:

RA(J2000)  = 19h 54m 40.51s
Dec(J2000) = -22d 32' 17.36"

with an uncertainty of 3' radius. The given uncertainty accounts
for both the statistical and systematic errors.

An analysis of the AGILE Gamma Ray Imager (GRID) data is in progress."


GRB_name: GRB091010A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10005
SUBJECT: SuperAGILE GRB is 091010 and not 090910
DATE:    09/10/10 05:42:54 GMT
FROM:    Marco Feroci at IASF/INAF  <sa.grb@iasf-roma.inaf.it>

Marco Feroci (INAF/IASF Rome) reports:

I made a mistake in the name of the GRB, that is GRB 091010
instead of GRB 090910, as cited in the previous circular.

The burst trigger time indicated in GCN #10004 was correct.

I apologize for the confusion.


GRB_name: GRB091010A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10006
SUBJECT: GRB 091010: Swift-XRT position
DATE:    09/10/10 20:24:43 GMT
FROM:    Raffaella Margutti at U. di Milano Bicocca  <raffaella.margutti@brera.inaf.it>

R. Margutti (INAF-OAB) &  C. Guidorzi (U. Ferrara) report on behalf
of the Swift XRT team:

We have analyzed the first orbit data (1.8 ks exposure) of the
Swift ToO observation of the SuperAGILE detected (Donnarumma et al.,
GCN Circ. 10004; Feroci, GCN Circ 10005) burst GRB 091010.

The Swift observation started on 2009 Oct 10 at 14:48:26 UT, about
43 ks after the SuperAGILE trigger.
We detected a single, uncatalogued X-ray source within the SuperAGILE
error box at RA, Dec =298.6661, -22.5181 which is equivalent to:

RA (J2000):  19h54m39.86s
Dec (J2000): -22:31:05.2

with an uncertainty of 4.3 arcsec (radius, 90% confidence).
The source lies 72 arcsec from the SuperAGILE position.

The source has a count rate of about 5.7E-02 count s^-1.
At the moment it is not possible to determine whether the source is
fading given the current statistics.

Burst Advocate for this burst is R. Margutti
(raffaella.margutti AT brera.inaf.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.)

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


GRB_name: GRB091010A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10007
SUBJECT: GRB 091010: Swift/UVOT Upper Limits
DATE:    09/10/10 21:54:59 GMT
FROM:    Peter Curran at MSSL  <pac@mssl.ucl.ac.uk>

P.A. Curran (MSSL-UCL) and R. Margutti (INAF-OAB) report on behalf of the 
Swift/UVOT team:

The Swift/UVOT began ToO observations of the field of the SuperAGILE 
detected GRB 091010 (Donnarumma et al., GCN 10004) on 2009 Oct 10 at 
14:48:26 UT.

No optical afterglow consistent with the Swift XRT position (Margutti et 
al., GCN 10006) is detected in the UVOT exposures.  Preliminary 3-sigma 
upper limits, using the UVOT photometric system (Poole et al. 2008, MNRAS, 
383, 627), for the exposures are:

Filter    Time(s)    Exp(s)     Mag
--------------------------------------
wh        4.41e4     498        >21.36
v         4.47e4     609        >19.86
u         4.35e4     567        >20.48

The values quoted above are not corrected for the Galactic extinction due 
to the reddening of E(B-V) = 0.10 in the direction of the burst (Schlegel 
et al. 1998).


GRB_name: GRB091010A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10008
SUBJECT: GRB 091010: GROND afterglow candidate
DATE:    09/10/11 04:11:35 GMT
FROM:    Andrea Rossi at TLS Tautenburg  <rossi@tls-tautenburg.de>

A. Rossi (Tautenburg), A. Rau, P. Afonso and J. Greiner (all MPE),
report on behalf of the GROND team:

Starting October 10 at 23h45 UT (21.03hrs post-burst) GROND (Greiner et 
al. 2008, PASP 120, 405) mounted at the 2.2m ESO/MPI telescope
at La Silla Observatory (Chile) imaged the field of GRB 091010
(Donnarumma et al., GCN #10004) simultaneously in the g'r'i'z'JHK bands.

Within the Swift-XRT circle (Margutti et al., GCN #10006) we find a 
single source at:
RA(J2000): 19:54:39.80
DEC(J2000): -22:31:03.9
with uncertainties of 0.5" in each coordinate.

The object is detected in the r' band with a preliminary AB magnitude of 
~22.2 calibrated against the GROND photometric zero point.  No correction
for Galactic foreground extinction of E(B-V)=0.14mag (Schlegel  et al.
1998, Apj, 500, 525) was applied.  Strongly variable sky conditions and
high seeing >2.5 arcsec) prevent reliable detections in others bands.


GRB_name: GRB090926A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10009
SUBJECT: RT-2 observation of the bright GRB 090926A
DATE:    09/10/11 06:48:11 GMT
FROM:    Sandip K. Chakrabarti at S.N. Bose Nat. Centre for Basic Sci.  <chakraba@bose.res.in>

S. K. Chakrabarti, A. Nandi, D. Debnath, T. C. Kotoch (ICSP, Kolkata, India),
A. R. Rao, J. P. Malkar, M. K. Hingar, V. K. Agrawal (TIFR, Mumbai, India), 
T. R. Chidambaram, P. Vinod, S. Sreekumar (VSSC, Thiruvananthapuram, India),
Y. D. Kotov, A. S. Buslov, V. N. Yurov, V. G. Tyshkevich, A. I. Arkhangelskij,
R. A.Zyatkov (MephI, Moscow, Russia) report:


The very bright GRB 090926A (FERMI-GBM trigger 275631628 / 090926181;
Bissaldi, GCN 9933) is detected by RT-2 Experiment onboard CORONAS-PHOTON
satellite at T0 = 04h 20m 27s (UT). The satellite was in LIGHT mode (pointing
towards the SUN) for a short duration at a high latitude in its orbit. During
this time, the GOOD time (away from the polar and SAA regions) observation was
for 348 sec starting at 04h 16m 55sec (UT) and ending at 04h 22m 43sec (UT).

The burst light curve consists of multiple peaks of total duration of ~ 17
sec, followed by a weak tail ending at ~ T0+30 sec. The strongest peak count
rate is ~ 1200 cts/sec.

This burst is also independently detected by KONUS-RF, another instrument
onboard CORONAS-PHOTON satellite (Golenetskii et al., 2009, GCN 9959).

Both RT-2/S and RT-2/G detectors have registered the burst profile of this
bright GRB in the energy band of 15  ~1000 keV with strongest emission in the
energy band of 60  215 keV.
 
The light curve is available at the web-site:
http://csp.res.in/rt2_files/grb090926-lc.html


GRB_name: GRB090929A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10010
SUBJECT: Detection of a short GRB 090929A by RT-2 Experiment
DATE:    09/10/11 06:52:39 GMT
FROM:    Sandip K. Chakrabarti at S.N. Bose Nat. Centre for Basic Sci.  <chakraba@bose.res.in>

S. K. Chakrabarti, A. Nandi, D. Debnath, T. C. Kotoch (ICSP, Kolkata, India),
A. R. Rao, J. P. Malkar, M. K. Hingar, V. K. Agrawal (TIFR, Mumbai, India), 
T. R. Chidambaram, P. Vinod, S. Sreekumar (VSSC, Thiruvananthapuram, India),
Y. D. Kotov, A. S. Buslov, V. N. Yurov, V. G. Tyshkevich, A. I. Arkhangelskij,
R. A.Zyatkov (MephI, Moscow, Russia) report:


The RT-2 Experiment onboard the CORONAS-PHOTON satellite has detected GRB
090929A (Fermi-GBM trigger 275891585/090929190; Rau, GCN 9962) which is
triggered at T0 = 04h 33m 04s (UT). The satellite was in the LIGHT mode
(pointing towards the SUN) with GOOD time (away from the polar and SAA
regions) observation of 1537 sec starting at 04h 21m 20sec (UT) and ending at
04h 46m 57sec (UT).

The burst light curve (1 sec bin) shows double peak profile of total duration
of around 5 sec. The strongest peak count rate is ~ 310 cts/sec.

This burst is also independently detected by KONUS-RF, another instrument
onboard CORONAS-PHOTON satellite (Golenetskii et al., 2009, GCN 9968).

Both RT-2/S and RT-2/G detectors have registered the prompt emission from the
GRB090929A in the energy band of 60  1000 with strongest emission in the
energy band of 60  215 keV.
 

The light curve is available at the web-site:
http://csp.res.in/rt2_files/grb090929-lc.html


GRB_name: GRB091010A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10011
SUBJECT: GRB 091010 optical upper limits
DATE:    09/10/11 11:29:01 GMT
FROM:    AAVSO GRB Network at AAVSO  <matthewt@aavso.org>

Arto Oksanen and Eric Southgate (The Hermitage Observatory, Sunshine 
Coast, QLD, Australia) report to the AAVSO International High Energy 
Network the following optical observations of the field of GRB 091010 (GCN 
Circ. #10004, Donnarumma et al.):

A. Oksanen and E. Southgate report an upper limit of approximately CR=17.5 
on the optical afterglow of GRB 091010 (GCN Circ. #10004, Donnarumma et 
al.).  The afterglow upper limit was measured relative to the star 
USNO-B1.0 0674-0991959.  A single, 120-second observation was made using 
an A&M 130-mm TMB APO with an SBIG ST2000 CCD camera and no filter.  The 
mid-point of the exposure was 2009 October 10, 11:19:17 UT, approximately 
8.6 hours after the SuperAGILE trigger.  The entire error box of the burst 
centered on RA 19h 54m 40.51s , Dec -22d 32m 17.36s was imaged; no new 
sources were detected using visual comparison of the CCD image with the 
DSS2 R-band plate of the area.

A stacked, 10 x 120-second image was also created from subsequent images 
of the field using the same camera.  The midpoint of this image was 2009 
October 10 11:47 UT, approximately 9.0 hours after the burst.  This image 
was visually examined, and no candidate objects were found; the image 
extends to approximately the same depth as the DSS2 red plate.

A FITS image of the initial observation is available at the following URL:
ftp://ftp.aavso.org/grb/ArtoOksanen_GRB091010_2455115.12128_.fits

The AAVSO thanks the Curry Foundation for its support of the AAVSO
International High Energy Network.


GRB_name: GRB091010A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10012
SUBJECT: GRB 091010: Enhanced XRT position
DATE:    09/10/11 12:41:43 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

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

Using 3934 s of XRT Photon Counting mode data and 4 UVOT images, 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 = 298.66550,
-22.51820 which is equivalent to:

RA (J2000):  19 54 39.72
Dec (J2000): -22 31 05.7

with an uncertainty of 1.9 arcsec (radius, 90% confidence). This is consistent
with the position of the candidate optical afterglow seen by GROND (Rossi et al.
GCN Circ. 10008).

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, MNRAS, 397, 1177).

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


GRB_name: GRB091010A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10013
SUBJECT: Konus-Wind observations of GRB 091010
DATE:    09/10/11 13:11:40 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

The long GRB 091010 (Donnarumma et al., GCN Circ. 10004; Feroci, GCN Circ 10005)
triggered Konus-Wind at T0=09788.232 s UT (02:43:08.232).

The burst light curve shows a multipeaked structure with a total
duration of ~8 s. The Konus-Wind light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB091010_T09788/

As observed by Konus-Wind the burst
had a fluence of (9.4  1.1)x10-6 erg/cm2,
and a 64-ms peak flux measured from T0 + 2.240s
of (8.3  1.0)x10-6 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).

The time-integrated spectrum of the burst (from T0 to T0+8.448 s)
is well fitted in the 20 keV - 2 MeV range by GRB (Band) model for which:
the low-energy photon index alpha = -1.20 (-0.28, +0.35),
the high energy photon index beta = -2.9(< -2.4),
the peak energy Ep = 119(-17, +19) keV (chi2 = 55/59 dof).

All the quoted errors are at the 90% confidence level.


GRB_name: GRB091010A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10014
SUBJECT: GRB 091010: RXTE detection
DATE:    09/10/11 15:16:55 GMT
FROM:    Peter Curran at MSSL  <pac@mssl.ucl.ac.uk>

A.L. Watts, A. Patruno, M. van der Klis (U.v. Amsterdam),
P. Casella (Southampton),
P.A. Curran (MSSL-UCL),
D. Altamirano, Y. Cavecchi, N. Degenaar, R. Kaur, M. Linares, P. Soleri,
R. Wijnands, A. Kamble (U.v. Amsterdam)
and N. Rea (ICE-CSIC/IEEC) report:


RXTE observations taken at the time of the SuperAGILE detected burst GRB 
091010 (Donnarumma et al., GCN Circ. 10004; Feroci, GCN Circ 10005) also 
recorded the event. 

The RXTE PCA detected two strong flares in emission, the first coinciding 
with the SuperAGILE trigger time (02:43:09 UT) and the other 2s later.  
Each flare lasted ~1s. There is also evidence for a third weaker flare 5s 
after the trigger. Peak count-rate (2-60 keV, 0.1s binning) for the first 
flare is 250 counts/s, and for the second flare is 500 counts/s. The RXTE 
lightcurve can be found at

http://staff.science.uva.nl/~pgcasell/GRB091010

At the time RXTE was observing XTE J1751-305, with nominal pointing 
direction

RA(J2000)  = 17h 51m 13.49s
Dec(J2000) = -30d 39' 23.4"

so was approximately 28 degrees off-axis from GRB 091010.  For this reason 
spectral and timing information will be degraded. Preliminary timing 
analysis reveals no significant periodic variability. The flares are not 
detected strongly below 30 keV. 

Although bright, this GRB did not have an exceptionally high peak flux.  
It is therefore perhaps a little surprising that RXTE was able to record 
this event so strongly given the offset angle. Reflections in the 
collimator may be responsible (see Laros et al. 1985).


We would like to thank the SuperAGILE team for providing us with their 
lightcurve for GRB 091010, which enabled us to confirm the RXTE 
identification. 


GRB_name: GRB090530A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10015
SUBJECT: GRB 090530A: Skynet/DSO Detections
DATE:    09/10/11 21:25:05 GMT
FROM:    Aaron LaCluyze at U.North Carolina  <lacluyze@physics.unc.edu>

A. Smith, A. LaCluyze, D. Reichart, D. Caton, L. Hawkins, J. Haislip, K. 
Ivarsen, A. Foster, J. Moore, A. Oza, M. Schubel, J. Styblova, A. Trotter, J. 
A. Crain, and M. Nysewander report:

Skynet observed the Swift/BAT localization of GRB 090530A (Cannizzo et al., GCN 
9438) with the 14" Dark Sky Observatory telescope in North Carolina beginning 
61.8 minutes after the trigger in RI.

We detect the afterglow (Cannizzo et al., GCN 9438).  Stacking only images that 
increase the limiting magnitude yields:

mean                                                        1-sig.  1-sig.
time                                                        sys.    stat.
since                                            cal.       cal.    cal.
trig.  tel.    exp.     fil.  magnitude          stars*     unc.    unc.
(m)            (# x s)                                      (mag)   (mag)

88.8   DSO-14  20 x 80  I     19.26 +0.32 -0.25  7 SDSS 7   0.050   0.001
102.2  DSO-14  23 x 80  R     19.53 +0.16 -0.14  10 SDSS 7  0.022   0.001

* Transformed using Jester et al., 2005, ApJ, 130, 873.


GRB_name: GRB090531A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10016
SUBJECT: GRB 090531A: Skynet/PROMPT Observations
DATE:    09/10/11 21:32:42 GMT
FROM:    Aaron LaCluyze at U.North Carolina  <lacluyze@physics.unc.edu>

A. LaCluyze, D. Reichart, J. Haislip, K. Ivarsen, A. Foster, J. Moore, A. 
Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. Nysewander 
report:

Skynet observed the Swift/BAT localization of GRB 090531A (Stamatikos et 
al., GCN 9454) with three of the 16" PROMPT telescopes at CTIO beginning 
6.1 minutes after the trigger in UVRI.

We do not detect the afterglow (Sbarufatti & Mangano, GCN 9525).  Stacking 
only images that increase the limiting magnitude yields:

mean                                                1-sig.  1-sig.
time                             3-sig.             sys.    stat.
since                            lim.    cal.       cal.    cal.
trig.  tel.      exp.      fil.  mag.    stars*     unc.    unc.
(m)              (# x s)                            (mag)   (mag)

6.5    PROMPT-5  1 x 40    I     17.6    32 SDSS 7  0.055   0.002
15.3   PROMPT-5  11 x 80   I     19.4    32 SDSS 7  0.055   0.000
84.0   PROMPT-3  75 x 80   U     19.3    7 SDSS 7   0.037   0.001
92.6   PROMPT-5  85 x 80   I     20.5    32 SDSS 7  0.055   0.000
                  + 1 x 40
94.1   PROMPT-4  43 x 80   V     21.1    37 SDSS 7  0.007   0.000
104.8  PROMPT-4  54 x 80   R     21.3    40 SDSS 7  0.018   0.000

* Transformed using Jester et al., 2005, ApJ, 130, 873.


GRB_name: GRB091010A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10017
SUBJECT: GRB 091010: Faulkes Telescope North observations
DATE:    09/10/12 13:02:36 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi (U. Ferrara), A. Gomboc (U. Ljubljana), D. Bersier,
Z. Cano, S. Kobayashi, A. Melandri, C.J. Mottram, C.G. Mundell,
R.J. Smith, I.A. Steele (Liverpool JMU), N.R. Tanvir
(U. Leicester) on behalf of a large collaboration report:

We began observing the SuperAGILE GRB 091010 (Donnarumma
et al. GCN Circ. 10004) with the 2-m Faulkes Telescope North
(FTN) on October 11, 04:54:49 UT (26.2 hours post burst)
with the BVRi' filters.

We clearly detect the GROND afterglow candidate (Rossi
et al. GCN Circ. 10008) with the Ri' filters with the
following magnitudes:

Telescope   Mid Time   Exposure  Filter   Mag
             (hours)     (s)
-------------------------------------------------------
FTN         27.5       7x300       i'     22.11 +- 0.15
FTN         27.6       6x300       R      22.2  +- 0.2
-------------------------------------------------------

Calibration was performed against a nearby USNOB-1 star:
RA(J2000), Dec(J2000)= 19:54:38.242, -22:31:27.11 assuming
R2=14.89 and i'=15.02.
Compared with GROND measurements, we cannot confirm any
fading of the source due to the closeness in time between
our observations.


GRB_name: GRB091010A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10018
SUBJECT: GRB 091010: Fermi GBM observation
DATE:    09/10/12 15:05:12 GMT
FROM:    David Gruber at MPE  <dgruber@mpe.mpg.de>

A. von Kienlin, E. Bissaldi and D. Gruber (all MPE)
report on behalf of the Fermi GBM Team:


"At 02:43:09.32 UT on 10 October 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 091010 (trigger 276835391 / 091010113),
which was also detected by SuperAGILE (Donnarumma et al., GCN 10004).
The GBM on-ground location is consistent with the Swift-XRT position
(Margutti et al. 2009, GCN 10006 and Evans et al. 2009, GCN 10012).

The angle from the Fermi LAT boresight is 55.7 degrees.
Moreover, this burst was bright enough to result in
a Fermi spacecraft repointing maneuver.

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

The GBM light curve consists of multiple peaks
with a duration (T90) of about 8.1 +/- 0.5 s (8-1000 keV).
The time-averaged spectrum from T0-0.128 s to T0+8.064 s is
best fit by a power law function with an exponential
high energy cutoff. The power law index is -1.11 +/- 0.03 and
the cutoff energy, parameterized as Epeak, is 150 (+6/-5) keV
(C-stat 446 for 359 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(1.09 +/- 0.02)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.9 s in the 8-1000 keV band
is 40.9 +/- 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: GRB080916C
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10019
SUBJECT: Radio observation of GRB080916c with ATCA
DATE:    09/10/13 09:06:49 GMT
FROM:    Aquib Moin at CIRA/ATNF  <aquib.moin@postgrad.curtin.edu.au>

Aquib Moin (Curtin Institute of Radio Astronomy / Australia Telescope
National Facility), Steven Tingay (Curtin Institute of Radio Astronomy),
Chris Phillips (Australia Telescope National Facility), Gregory Taylor
(University of New Mexico), Mark Wieringa (Australia Telescope National
Facility) and Ralph Martin (Perth Observatory) report:

We observed the XRT position of the GRB080916c (GCN 8261) at 5.5 GHz
with the Australia Telescope Compact Array (ATCA) between 14:00:00 UT
and 20:00:00 UT on July 01, 2009.

We did not detect a radio source at the XRT position of the GRB080916c
(GCN 8261). The radio flux density at the afterglow position found out
to be 0.230 +/- 0.180 mJy/beam (1-sigma). The compact array was in its
most compact configuration.

The Australia Telescope Compact Array (/ Parkes telescope / Mopra
telescope / Long Baseline Array) is part of the Australia Telescope
which is funded by the Commonwealth of Australia for operation as a
National Facility managed by CSIRO.

See the 5.5 GHz field image at: 

http://cira.ivec.org/dokuwiki/doku.php/grb/grb080916c_field_image


GRB_name: GRB090926A
Detection_method: Fermi LAT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10020
SUBJECT: Radio observation of GRB090926a with ATCA
DATE:    09/10/13 09:10:17 GMT
FROM:    Aquib Moin at CIRA/ATNF  <aquib.moin@postgrad.curtin.edu.au>

Aquib Moin (Curtin Institute of Radio Astronomy / Australia Telescope
National Facility), Dale A. Frail (National Radio Astronomy
Observatory), Steven Tingay (Curtin Institute of Radio Astronomy),
Jean-Pierre Macquart (Curtin Institute of Radio Astronomy) report:

We observed the UVOT-enhanced XRT position (GCN 9936) of the Fermi
LAT/GBM burst GRB090926a (GCN 9933, 9972) at 5.5 GHz with the Australia
Telescope Compact Array (ATCA) between 05:00:00 UT and 10:00:00 UT on
October 01, 2009. The ATCA was in its most compact configuration giving
a synthesized beam of 138 x 78 arcsec.

We did not detect a radio source at the XRT position of the GRB090926a
(GCN 9936). The radio flux density at the GRB position found out to be
-0.271  0.727 mJy/beam.

No further observations are planned.

The Australia Telescope Compact Array (/ Parkes telescope / Mopra
telescope / Long Baseline Array) is part of the Australia Telescope
which is funded by the Commonwealth of Australia for operation as a
National Facility managed by CSIRO.

See the GRB field image at: 

http://cira.ivec.org/dokuwiki/doku.php/grb/grb090926a_field_image


GRB_name: GRB090927A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10021
SUBJECT: Radio observation of GRB090927 with ATCA
DATE:    09/10/13 09:12:09 GMT
FROM:    Aquib Moin at CIRA/ATNF  <aquib.moin@postgrad.curtin.edu.au>

Aquib Moin (Curtin Institute of Radio Astronomy / Australia Telescope
National Facility), Dale A. Frail (National Radio Astronomy
Observatory), Steven Tingay (Curtin Institute of Radio Astronomy),
Jean-Pierre Macquart (Curtin Institute of Radio Astronomy) report:

We observed the enhanced Swift-XRT position of the GRB090927 (GCN 9950)
at 5.5 GHz with the Australia Telescope Compact Array (ATCA) between
05:00:00 UT and 10:00:00 UT on October 01, 2009. The ATCA was in its
most compact configuration giving a synthesized beam of 126 x 76 arcsec.

We did not detect a radio source at the XRT position of the GRB090926a
(GCN 9950). The radio flux density at the GRB position found out to be
0.036  0.172 mJy/beam.

No further observations are planned.

The Australia Telescope Compact Array (/ Parkes telescope / Mopra
telescope / Long Baseline Array) is part of the Australia Telescope
which is funded by the Commonwealth of Australia for operation as a
National Facility managed by CSIRO.

See the GRB field image at: 

http://cira.ivec.org/dokuwiki/doku.php/grb/grb090927_field_image


GRB_name: GRB091010A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10022
SUBJECT: GRB 091010: AGILE-MCAL measurement and GRID upper limit
DATE:    09/10/13 15:44:40 GMT
FROM:    Martino Marisaldi at INAF-IASF  <marisaldi@iasfbo.inaf.it>

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


"The long GRB 091010 localized by SuperAGILE (Donnarumma et al., GCN 
10004) triggered also the MCAL instrument onboard AGILE, sensitive in
the energy range 330 keV - 100 MeV, at 02:43:10 UT (T0).
As seen by MCAL the burst has a double-peaked light curve, with a
duration of 3.5 s.
The time integrated spectrum in the time interval [T0-1.5 s, T0+2.0 s]
can be fit in the energy range 400 keV - 2 MeV with a single powerlaw
with photon index -3.0 (-0.6, +0.8) (reduced chi2 = 1.09 with 9 d.o.f.).
The estimated fluence is (1.40 +/- 0.3)x10-6 erg/cm2 in the same energy
range.
All reported errors are at the 90% confidence level.
No significant emission is detected above 2 MeV.

The photon index and fluence are consistent with those reported by
Konus-Wind (Golenetskii et al., GCN 10013), when the different energy
range is accounted for.

No significant emission is detected by AGILE GRID.
A 3-sigma Upper Limit for emission in the GRID energy range (E>30 MeV)
in the same 3.5 seconds time interval used for MCAL analysis can be
placed at 0.043 ph/cm2.
Using a 60-seconds time interval starting from T0 the 3-sigma Upper
Limit is 0.1 ph/cm2."


GRB_name: GRB091010A
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10023
SUBJECT: GRB 091010: Suzaku WAM observation of the prompt emission
DATE:    09/10/15 09:56:22 GMT
FROM:    Masanori Ohno at ISAS/JAXA  <ohno@astro.isas.jaxa.jp>

N. Vasquez (Tokyo Tech.), M. Ohno, M. Suzuki,M. Kokubun,
T. Takahashi (ISAS/JAXA), K. Yamaoka (Aoyama Gakuin U.),
N. Ohmori, E. Sonoda, K. Kono, H. Hayashi, A. Daikyuji,
Y. Nishioka, K. Noda, M. Yamauchi (Univ. of Miyazaki),
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),
Y. E. Nakagawa, T. Tamagawa (RIKEN), S. Hong (Nihon U.),
S. Sugita (Nagoya U.)on behalf of the Suzaku WAM team, report:


The long GRB 091010 (Fermi trigger #276835391/091010113,
von Kienlin et al., GCN10018, SuperAGILE Donnarumma et al., GCN 10004)
triggered the Suzaku Wide-band  All-sky Monitor (WAM) in a energy  
range from
  50 keV to 5 MeV at 02:43:09.50 UT (=T0).

The observed light curve shows a multi-peaked structure, starting at
T0 s and ending at T0+7s, with a total duration (T90) of 6.5 s.
The fluence in 100 - 1000 keV was 6.22(+0.48,-0.42) x 10-6 erg/cm^2.
The 1-s peak flux measured from T0+1 s was 9.91(+0.89,-1.03) photons/s/ 
cm^2
in the same energy range.

Preliminary result shows that the time-averaged spectrum from
T0-1s  to T0+7s is well fitted by a single power-law with
a photon index of 2.50 (+0.24,-0.22) (chi^2/d.o.f = 11.7/8).
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: GRB091010A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10024
SUBJECT: GRB 091010: Swift-XRT refined analysis
DATE:    09/10/15 14:19:46 GMT
FROM:    Raffaella Margutti at U. di Milano Bicocca  <raffaella.margutti@brera.inaf.it>

R. Margutti (INAF-OAB) reports on behalf of the Swift-XRT team:

The Swift ToO observations of the SuperAGILE GRB 091010
(Donnarumma et al., GCN Circ. 10004; Feroci, GCN Circ. 10005) started
on 2009 Oct 10th at 14:48:26 UT. The XRT data set consists of 9 ks
exposure in PC mode. The UVOT-enhanced XRT position was given by
Evans et al. in GCN Circ. 10012.

The X-ray source reported by Margutti & Guidorzi, GCN Circ. 10006
has faded to a level of (2.4 +/- 1.0)e-3 count/sec, with a best fit
power-law decay index of alpha=-1.4 +/- 0.6 .
This source is thus confirmed as the afterglow of GRB 091010.

The spectrum extracted in the time interval 43-50 ks contains about
170 photons and can be fitted using an absorbed power law model.
Spectral channels have been grouped so as to have 5 counts per bin
and then weighted using the Churazov method (Churazov et al. 1996).
The best fit photon index is found to be 2.3 +/- 0.4. The spectrum
shows evidence of absorption at the level of (1.9 +/- 0.1)e21 cm-2,
in excess of the Galactic value in the direction of the burst which
is 8.1e20 cm-2, Kalberla et al. 2005.
The observed (unabsorbed) flux over this time interval is 1.5e-12
(2.8e-12) erg cm^-2 s^-1. The counts to observed (unabsorbed) 0.3-10 keV
flux conversion factor deduced from this spectrum is 3.6 x 10^-11
(6.6 x 10^-11) erg cm^-2 count^-1.

All quoted errors are at 90% confidence level.

The results of the xrt automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020116.

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


GRB_name: GRB090815A
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10025
SUBJECT: GRB 090815: a faint long GRB localized by INTEGRAL
DATE:    09/10/16 13:22:55 GMT
FROM:    Carlo Ferrigno at IAAT/ISDC  <carlo.Ferrigno@unige.ch>

C. Ferrigno (ISDC, Versoix/IAAT, Tuebingen), D.Gotz (CEA-Saclay),  
S.Mereghetti, A.Paizis (IASF-Milano), E. Bozzo, M. Beck (ISDC,  
Versoix), and J.Borkowski (CAMK, Torun) on behalf of the IBAS  
Localization Team report:

A faint long GRB with duration of about 100 s has been detected by  
IBAS in IBIS/ISGRI data at 23:00:17 UTC on August 15th. No automatic  
alert has been issued because the trigger was at low significance.

Interactive off-line analysis has allowed to confirm the GRB nature of  
the trigger.

The refined coordinates (J2000) are:

RA:   306.13 [degrees]   DEC: -6.17 [degrees]

with an uncertainty of 3 arcmin (90% c.l.).

The soft spectrum of the GRB (only detected in the 20-40 keV energy  
range) and the long, slowly rising light curve may indicate a highly  
redshifted burst. Follow-up observations at other wavelengths are  
encouraged.

The light curve of the GRB will be posted at http://ibas.iasf-milano.inaf.it/IBAS_Results.html

This message can be cited.





--
\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
Carlo Ferrigno Institut fr Astronomie
und Astrophysik Tbingen (IAAT)
and
ISDC Data Centre for Astrophysics
Chemin d'cogia 16
CH-1290 Versoix Switzerland
Office +41.22.3792178
mobile (IT) +39.333.3599421
mobile (CH) +41.78.9210855
E-mail: Carlo.Ferrigno@unige.ch
Home Page: http://www.ifc.inaf.it/~ferrigno/
///////////////////////////////////////////////


GRB_name: GRB091015A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10026
SUBJECT: GRB 091015: correction to GCN 10025
DATE:    09/10/16 13:36:13 GMT
FROM:    Diego Gotz at CEA  <diego.gotz@cea.fr>

D. Gotz (CEA Saclay) on behalf of the IBAS Team reports:

GCN number 10025 contains a mistake: the burst name is 091015 since it has been detected on October 15th, and not on August 15th as stated ih the GCN.


GRB_name: GRB091010A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10027
SUBJECT: GRB 091010: optical afterglow candidate rejection
DATE:    09/10/16 15:16:32 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi (U. Ferrara), A. Melandri, C.G. Mundell, D. Bersier,
Z. Cano, N.R. Clay, S. Kobayashi, C.J. Mottram, R.J. Smith,
I.A. Steele (Liverpool JMU), A. Gomboc (U. Ljubljana),
N.R. Tanvir (U. Leicester) on behalf of a large collaboration
report:

We re-observed the optical afterglow candidate (Rossi et al.
GCN Circ. 10008) of the SuperAGILE GRB 091010 (Donnarumma
et al. GCN Circ. 10004) with the 2-m Faulkes Telescope South
(FTS) on October 16, 09:27:33 UT (6.3 days post burst)
with the Ri' filters.

The source is still clearly detected in both filters.
Comparison with our previous values obtained at 1 day
post burst (Guidorzi et al. GCN Circ. 10017) shows that
the source did not fade appreciably.
We derived an upper limit to the possible power-law
decay index of alpha<0.5 (90% confidence) from 1 to
6 days post burst, flux~t^(-alpha).
Given that a comparably shallow and long-lasting decay
has never been observed, we can confidently rule out
this source as the optical afterglow of GRB 091010.

Telescope  Mid Time   Exposure  Filter   Mag
           (days)     (s)
-----------------------------------------------------
FTS         6.29       6x300       i'     22.2 +- 0.3
FTS         6.31       6x300       R      22.3 +- 0.3
-----------------------------------------------------

Calibration was the same as that used in our previous
report (GCN Circ. 10017).


GRB_name: GRB090726A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10028
SUBJECT: GRB 090726 R band observations
DATE:    09/10/16 21:08:29 GMT
FROM:    Janos Kelemen at Konkoly Obs/Hungary  <kelemen@konkoly.hu>

J. Kelemen (kelemen at konkoly.hu) on behalf of the GRB OT observing program
at the Konkoly Observatory.
We present photometry of the source reported by Moskvitin, Fatkhullin and
Valeev (GCN 9709) which was found on a previous survey images made for 
asteroid astrometry. The object was observed from the Mountain Station of the
Konkoly Observatory with a 60/90 cm  Schmidt telescope using R filter and a
CCD. The exposures were of 300 s. The table contains the time since the Swift
GRB detection to the middle of exposure in seconds, R magnitude and formal
1-sigma magnitude error estimate. Comparison stars were from the USNO A2.0
catalogue. Aperture photometry results obtained using the ASTROMETRICA
astrometry and photometry package.

 Time     Mag     Error.      Flag.
  [s]     [R]    [1-sigma]  
-------------------------------------
  2010   18.21   0.05
  2730   18.32   0.05
  4530   18.82   0.05
 78330   20.60   0.2      Upper Limit
-------------------------------------

This message can be cited. 


GRB_name: GRB091015A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10029
SUBJECT: GRB 091015: RTT150 optical observations
DATE:    09/10/16 22:15:32 GMT
FROM:    Rodion Burenin at IKI, Moscow  <rodion@hea.iki.rssi.ru>

R. Gumerov, A. Nemtinov, I. Bikmaev, N. Sakhibullin (KSU/AST),
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI),
M. Parmaksizoglu, I. Khamitov, Z. Eker (TUG), 
U. Kiziloglu (METU), E. Gogus (Sabanci Uni.)

report:

The optical afterglow of GRB 091015 (Ferrigno et al., GCN 10025, Gotz et
al., GCN 10026) was observed with Russian-Turkish 1.5-m telescope (RTT150,
Bakirlitepe, TUBITAK National Observatory, Turkey) in partially cloudy
conditions. We obtained a serie of 60s images in R centered at October 16,
17:40 UT, i.e. 0.76 days after the burst. The limiting magnitude in combined
image is estimated as R=~22. We do not detect any new optical object as
compared to DSS II red plate.


GRB_name: GRB091010A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10030
SUBJECT: GRB 091010: optical obsevation 
DATE:    09/10/17 02:11:22 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

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

We observed the field of SuperAGILE GRB 091010 (Donnarumma et al. GCN 10004) 
with   Shajn telescope of  CrAO on Oct. 12 between  (UT) 16:55:18 - 
18:09:40. In the XRT error circle  (Margutti  et al. GCN 10006)  we detect a 
single object at coordinates (J2000) RA:  19 54 39.80 Dec: -22 31 04.71. The 
coordinates of the object coincide with OT candidate reported by Rossi et 
al. (GCN 1008).
The photometry against nearby USNO-B1.0 stars (0674-0991940 RA:19 54 39.26 
Dec: -22 31 29.7 R=18.18, 0674-0991922 RA:19 54 38.07 Dec: -22 31 12.4 
R=17.27)   is following:

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

2.62   R     71x60     22.40 +/- 0.17

Our photometry confirm the absence of variability of the OT candidate (Rossi 
et al.GCN 1008, Guidorzi et al.GCN 10027).  However the object looks like 
extended in E-W direction, and can be a candidate in a host galaxy of GRB 
091010.
The combined image can be found in 
http://grb.rssi.ru/GRB091010/GRB091010_091012_R_ZTSh.gif

 


GRB_name: GRB091003A
Detection_method: Fermi LAT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10031
SUBJECT: GRB 091003: Gemini-N redshift of possible host galaxy
DATE:    09/10/18 19:20:08 GMT
FROM:    Antonino Cucchiara at PSU  <cucchiara@astro.psu.edu>

A. Cucchiara, D. B. Fox (PSU), S. B. Cenko (U. Berkeley), N. Tanvir (U. 
Leicester),
E. Berger (Harvard U.) report on behalf of a larger collaboration:

"On October 17.20 UT we observed  the possible host galaxy of the Fermi/LAT
GRB 091003 (McEnery at al, GCN 9985 and Perley et al. GCN 9997) with
Gemini GMOS-N.

We took a sequence of 2 spectra of 1800s each covering the 6000-10000A
wavelength range. The spectra clearly show emission lines which we 
interpreted
as [OII]3727, Hbeta and we resolved the [OIII]4959,5007 doublet.
All these identifications are consistent with redshift z = 0.8969 for 
this galaxy.

The galaxy is detected in our 300s R-band acquisition image.
The estimated magnitude, calibrated using 3 SDSS stars is:

R = 22.65 +- 0.05 mag

This value is brighter than the cataloged magnitude, which may indicate a
contribution of the afterglow. After subtracting the contribution
of the galaxy we derive an estimate of the OT flux, R = 23.65 +- 0.05 mag.

We thank the Gemini staff for performing these observations."


GRB_name: GRB091003A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10032
SUBJECT: GRB 091003: Possible Supernova Component
DATE:    09/10/18 19:56:31 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <Stephen.T.Holland@nasa.gov>

S. T. Holland (CRESST/USRA/GSFC) reports:

     The excess light from the z = 0.8969 host galaxy candidate for
GRB 091003 (Cucchiara et al. 2009, GCNC 10031) correspond to a
rest-frame B-band absolute magnitude of approximately M_B = -20 mag.
This is approximately consistent with the peak rest-frame B-band
absolute magnitude of SN1998bw.  The Cucchiara et al. (2009, GCNC
10031) observation was taken on 2009 Oct 17, which corresponds to
approximately seven days after the burst in the rest frame, which is
approximately the expected time of maximum light for a SN Ib/c.
Therefore, we suggest that the excess light seen in this galaxy may be
due to a supernova component of GRB 091003.  The lack of an observed
optical afterglow at earlier times supports this interpretation.
Further spectroscopic observations are encouraged to test this
hypothesis.


GRB_name: GRB091003A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10033
SUBJECT: Fwd: GRB 091003: Possible Supernova Component Retraction
DATE:    09/10/18 20:04:51 GMT
FROM:    Stephen Holland at USRA/NASA/GSFC/SSC  <Stephen.T.Holland@nasa.gov>

S. T. Holland (CRESST/USRA/GSFC) reports:

     I would like to retract GCNC 10032 (Holland 2009).  It was sent  
in error due to a confusion between GRB 091003 and GRB 091010.  I  
apologize for the error and any confusion that it may have caused.


GRB_name: GRB091018A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10034
SUBJECT: GRB 091018: Swift detection of a burst with optical afterglow
DATE:    09/10/18 21:08:34 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

M. Stamatikos (OSU/NASA/GSFC), D. N. Burrows (PSU),
J. R. Cummings (NASA/UMBC), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC),
C. Gronwall (PSU), C. Guidorzi (U Ferrara),
S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),
W.B Landsman (GSFC), C. B. Markwardt (CRESST/GSFC/UMD),
F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester),
D. M. Palmer (LANL), M. Perri (ASDC), J. L. Racusin (NASA/GSFC/ORAU)
and G. Stratta (ASDC) report on behalf of the Swift Team:

At 20:48:19 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 091018 (trigger=373172).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 32.211, -57.526 which is 
   RA(J2000) = 02h 08m 51s
   Dec(J2000) = -57d 31' 34"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single smooth
FRED peak a duration of about 10 sec.  The peak count rate
was ~16000 counts/sec (15-350 keV), at ~2 sec after the trigger. 

The XRT began observing the field at 20:49:20.5 UT, 60.9 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 32.18587, -57.54749 which
is equivalent to:
   RA(J2000)  = 02h 08m 44.61s
   Dec(J2000) = -57d 32' 51.0"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 91 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 (2.81e+20
cm^-2, Kalberla et al. 2005), with an excess column of 1.4
(+1.00/-0.93) x 10^21 cm^-2 (90% confidence). 

The initial flux in the 2.5 s image was 4.40e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 68 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 02:08:44.61 = 32.18588
  DEC(J2000) = -57:32:53.8  = -57.54827
with a 90%-confidence error radius of about 0.61 arc sec. This position is 3.8
arc sec. from the center of the XRT error circle. The estimated magnitude is
14.60 with a 1-sigma error of about 0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.03. 

Burst Advocate for this burst is M. Stamatikos (Michael.Stamatikos-1 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: GRB091015A
Detection_method: IBAS
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10035
SUBJECT: GRB 091015: Skynet/PROMPT Observations
DATE:    09/10/18 21:20:57 GMT
FROM:    Aaron LaCluyze at U.North Carolina  <lacluyze@physics.unc.edu>

A. LaCluyze, D. Reichart, K. Ivarsen, J. Haislip, R. Egger, A. Foster, J. 
Moore, A. Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. 
Nysewander report:

Skynet observed ~90% of the INTEGRAL/IBAS localization of GRB 091015 
(Ferrigno et al., GCN 10025; Gotz, GCN 10026) with one of the 16" PROMPT 
telescopes at CTIO beginning 25.3 hours after the the trigger in z.

We do not detect any uncatalogued sources.  Stacking only images that 
increase the limiting magnitude yields:

mean                                                  1-sig.  1-sig.
time                             3-sig.               sys.    stat.
since                            lim.    cal.         cal.    cal.
trig.  tel.      exp.      fil.  mag.    stars*       unc.    unc.
(h)              (# x s)                              (mag)   (mag)

27.1   PROMPT-5  144 x 80  z*    21.2    319 USNO B1  0.313   0.000

* Calibrated to I


GRB_name: GRB091018A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10036
SUBJECT: GRB 091018: ROTSE-III Detection of Optical Counterpart 
DATE:    09/10/18 21:34:32 GMT
FROM:    Brad Schaefer at LSU  <schaefer@grb.phys.lsu.edu>

B. E. Schaefer (Louisiana State) and 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 091018 (Swift trigger 373172, Stamatikos et al., GCN
10034). The first image was at 20:57:36.1 UT, 556.6 s after the burst
(11.1 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:

     02:08:44.6      -57:32:53.6    (J2000), 

with positional uncertainty of 1" or better

start UT     mag     mlim(of image)
----------------------------------
20:57:36.1     15.4     16.4 


With this, we confirm the optical afterglow reported in GCN 10034 as a
UVOT detection.  The source is rapidly fading.  A jpeg image is available 
at
http://www.rotse.net/images/gsb373172_3c01_img.jpg Note that the object
numbered 14 (in the lower of the two circles) is the candidate in
question.

Continuing observations are in progress. 


GRB_name: GRB091018A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10037
SUBJECT: GRB 091018: Enhanced Swift-XRT position
DATE:    09/10/19 00:31:06 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 1175 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 091018, 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 = 32.18588, -57.54825 which is equivalent
to:

RA (J2000): 02h 08m 44.61s
Dec (J2000): -57d 32' 53.7"

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, MNRAS, 397, 1177).

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


GRB_name: GRB091018A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10038
SUBJECT: GRB091018: Magellan Echellette Observations
DATE:    09/10/19 01:49:14 GMT
FROM:    Hsiao-Wen Chen at U Chicago  <hchen@oddjob.uchicago.edu>

Hsiao-Wen Chen, Jennifer Helsby (UChicago), Stephen Shectman, Ian 
Thompson, Jeffrey Crane (Carnegie Observatory) report on behalf of a 
larger collaboration:

"We observed the afterglow of GRB091018 reported by Stamatikos et al. (GCN
10034) and confirmed by Schaefer et al. (GCN10036) using the MagE 
echellette spectrograph on the Magellan Clay Telescope.  The observations 
started at UT 00:28 on October 19, 2009, ~ 3.5 hours after the inital 
trigger.  We obtained 2x900s exposures.  Our preliminary reduction shows 
that the afterglow spectrum displays strong absorption transitions due to 
MgII, FeII, MnII at redshift z=0.971, which we tentatively identify as the 
host redsdhift of the GRB.

Further analysis is underway.

This message may be cited."


GRB_name: GRB091018A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10039
SUBJECT: GRB 091018: GROND observations
DATE:    09/10/19 02:13:51 GMT
FROM:    Robert Filgas at MPI  <filgas@mpe.mpg.de>

R. Filgas, T. Kruehler, A. Yoldas (all MPE Garching),
S. Klose (TLS Tautenburg), and
J. Greiner (MPE Garching), report on behalf of the GROND team:

GROND (Greiner et al. 2008, PASP 120, 405), the 7-channel imager mounted
at the 2.2m ESO/MPI telescope at La Silla Observatory (Chile), started
follow-up observations of GRB 091018 (Stamatikos et al. 2009, GCN 10034)
on October 18, at 23:47 UTC (~4 hrs after the burst).

For the afterglow candidate reported by Stamatikos et al. we
estimate the following preliminary magnitudes (in the AB system):

g'= 19.061 +/- 0.010
r'= 18.853 +/- 0.007
i'= 18.732 +/- 0.013
z'= 18.70  +/- 0.10
J = 18.3   +/- 0.1
H = 18.2   +/- 0.1
K = 17.9   +/- 0.1

calibrated against GROND zeropoints.


GRB_name: GRB091018A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10040
SUBJECT: GRB 091018: Swift-BAT refined analysis
DATE:    09/10/19 02:57:39 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.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-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 091018 (trigger #373172)
(Stamatikos, et al., GCN Circ. 10034).  The BAT ground-calculated position is
RA, Dec = 32.191, -57.546 deg, which is 
   RA(J2000)  =  02h 08m 45.9s 
   Dec(J2000) = -57d 32' 45.0" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 84%.
 
The mask-weighted light curve shows the FRED peak starting at ~T-5 sec,
peaking at T+1.1 sec, and ending at ~T+20 sec.  T90 (15-350 keV) is
4.4 +- 0.6 sec (estimated error including systematics).
 
The time-averaged spectrum from T-0.3 to T+7.7 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 1.77 +- 0.24, 
and Epeak of 19.2 +18,-11 keV (chi squared 40.01 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 1.4 +- 0.1 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T+0.80 sec in the 15-150 keV band is
10.3 +- 0.4 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 2.30 +- 0.06 (chi squared 52.2 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/373172/BA/


GRB_name: GRB091018A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10041
SUBJECT: GRB091018: Swift/UVOT observations
DATE:    09/10/19 04:12:08 GMT
FROM:    Wayne Landsman at GSFC/SSAI  <wayne.b.landsman@nasa.gov>

W.B. Landsman (NASA/GSFC) and M. Stamatikos (OSU/NASA/GSFC) report on  
behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 091018  
69s after the BAT trigger (Stamatikos et al., GCN 10034).    The  
afterglow is well-detected in all seven UVOT filters at the position 
reported by Stamatikos et al.     The initial magnitudes are as follows:

Filter    T_start(s) Exp(s)      Mag
white         69    147     14.57  0.012
white        860    147     16.48  0.018

u            281    246     15.07  0.017
u           6911    197     18.04  0.08

v            610     19     16.4  0.14
b            536     19     16.4  0.08
uvw1         660     20     15.9  0.12
uvm2         635     20     15.7  0.16
uvw2         586     20     16.1  0.15

The detection in the uvw2 filter indicates a redshift less than z = 1.1, 
consistent with the value of z= 0.971 reported by the Magellan group ( 
Chen et al., GCN 10038).

The values quoted above are not corrected for the Galactic extinction  
due to the reddening of E(B-V) = 0.029 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: GRB091018A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10042
SUBJECT: GRB 091018: VLT/X-shooter spectra
DATE:    09/10/19 16:24:15 GMT
FROM:    Antonio Deugarte at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (OAB-INAF), P. Goldoni
(APC/Univ. Paris 7 and SAp/CEA), C.C. Thoene
(OAB-INAF), N. Tanvir (Univ. Leicester),
P. Jakobsson (Univ. of Iceland), S.D. Vergani
(APC/Univ. Paris 7), H. Flores (Paris Obs.)
D. Malesani (DARK/NBI), A. Levan (Univ.
Warwick) and J.P.U. Fynbo (DARK/NBI) report
on behalf of the X-shooter GRB collaboration:

X-shooter observed the afterglow of GRB 091018
(Stamatikos et al. CGN 10034) starting at 23:58 UT
of the 18th Oct 2009. The observation consisted of
4 x 600s exposures, having a mean epoch of October
19.0148 UT, 3.53 hours after the burst. In the spectra
we detect the continuum in the complete range from
3000 to 24800 Angstroms. On a preliminary analysis
we find several absorption features including AlII
(1670), AlIII (1854, 1862), FeII (2260, 2344, 2374,
2382, 2586, 2600) MnII (2576, 2594, 2606), MgII
(2797, 2803), MgI (2852), CaII (3934, 3969) at a
common redshift of 0.9710 +/- 0.0003, consistent with
the observation reported by Chen et al. (GCN 10038).
There is also a tentative detection of [OII], [OIII] and
H-alpha emission lines from the host galaxy at the
same redshift. Further analysis is ongoing.

We thank the ESO observing staff, in particular A.
Smette, C. Martayan and C. Cid.


GRB_name: GRB091018A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10043
SUBJECT: GRB 091018: BOOTES-3 observations
DATE:    09/10/19 19:49:59 GMT
FROM:    Antonio Deugarte at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (INAF-OAB), P. Kubanek (U. Valencia, IAA-CSIC),
M. Jelinek, A.J. Castro-Tirado, J. Gorosabel, R. Cunniffe, S. Guziy  
(IAA-CSIC),
B.A. Allen (Vintage Lane Obs.) and P. Yock (Auckland Univ.) report:

We have observed the afterglow of GRB 091018 (Stamatikos et al. CGN
10034) with the 0.6m Yock-Allen telescope (BOOTES-3) located in
Blenheim (New Zealand). A combination of 21x30s unfiltered images with
mean epoch Oct. 19.625 UT (18.2 hours after the burst) shows the  
afterglow
at a magnitude of R=20.0+/-0.3. The photometry has been obtained using
as comparison 5 USNO-B1.0 stars. This magnitude implies a rough
decay slope of alpha = 0.7 +/- 0.2 (with F ~ t^(-alpha)) as compared to
the values of Filgas et al. (GCN 10039). Further analysis is ongoing.


GRB_name: GRB091018A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10044
SUBJECT: GRB 091018 : Faulkes Telescope South Observations
DATE:    09/10/19 20:37:10 GMT
FROM:    Zach Cano at ARI/John Moores Liverpool  <zec@astro.livjm.ac.uk>

Z. Cano (Liverpool JMU), C. Guidorzi (U. Ferrara), D. Bersier, N.R. Clay,
S. Kobayashi, A. Melandri, C.G. Mundell, C.J. Mottram, R.J. Smith, I.A.
Steele (Liverpool JMU), A. Gomboc (U. Ljubljana), N.R. Tanvir (U.
Leicester) on behalf of a larger collaboration report:

The Faulkes Telescope South (Australia) observed the field of GRB 091018
(Swift trigger=373172, Stamatikos et al., GCN 10034) on 2009 October 19.

We clearly detect the afterglow candidate (Schaefer & Pandey, GCN 10036;
Chen et al., GCN 10038; Filgas et al., GCN 10039; Landsman & Stamatikos,
GCN 10041; A. de Ugarte Postigo et al., GCN 10042 & GCN 10043) in the Ri'
filters with the following magnitudes:

Filter   mag        merr      T-To (hr)
---------------------------------------
I       19.73      0.06      15.17
I       20.13      0.08      20.95
R       19.67      0.06      15.72
R       20.06      0.08      20.95

As calibrated against nearby USNO object 0342-0026807 (R2 = 16.34, I2 =
16.22).

From the images obtained on FTS we derive preliminary decay rates of:
alpha_I = 1.1 +/- 0.3 & alpha_R = 1.2 +/- 0.3.


GRB_name: GRB091018A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10045
SUBJECT: Konus-RF observation of GRB 091018
DATE:    09/10/19 21:35:13 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <lanzelot@mail.ru>

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

The soft GRB 091018 (Swift-BAT trigger #373172: Stamatikos et al.,
GCN 10034, Markwardt et al., GCN 10040) triggered Konus-RF
at T0=74900.651 s UT (20:48:20.651).

The burst light curve shows a single pulse with a duration of ~5 s.

As observed by Konus-RF the burst
had a fluence of 1.44(-0.16, +0.19)x10^-6 erg/cm2,
and a 256-ms peak flux measured from T0-0.280 s
of 4.32(-0.94, +0.97)x10^-7 erg/cm2/s
(both in the 20 keV - 1 MeV energy range).

The time-integrated spectrum of the burst (from T0-2s to T0+3s)
is well fitted (in the 10 keV - 1 MeV range)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep), with
alpha = -1.53(-0.39, +0.59),  and
Ep = 28(-16, +10) keV (chi2 = 83.4/94 dof).
Fitting by GRB (Band) model yields the same alpha and Ep,
and only an upper limit on the high energy
photon index: beta < -2.44 (chi2 = 81.7/93 dof).

All the quoted values are preliminary.
All the quoted errors are at the 90% confidence level.

Assuming z = 0.971 (Chen et al., GCN 10038) and
a standard cosmology model with H_0 = 70 km/s/Mpc, Omega_M = 0.27,
Omega_Lambda = 0.73, the isotropic energy release E_iso ~3.7x10^51 erg,
the peak luminosity (L_iso)_max ~2.2x10^51 erg/s,
and Ep_rest ~55 keV.

The Konus-RF light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB091018_T74900/KRF/


GRB_name: GRB091018A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10046
SUBJECT: GRB 091018:  Skynet/PROMPT Observations of Fading
DATE:    09/10/19 23:59:19 GMT
FROM:    Aaron LaCluyze at U.North Carolina  <lacluyze@physics.unc.edu>

A. LaCluyze, D. Reichart, J. Haislip, K. Ivarsen, R. Egger, A. Foster, J. 
Moore, A. Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. 
Nysewander report:

Skynet observed the Swift/BAT localization of GRB 091018 (Stamatikos et 
al., GCN 10034) with four of the 16" PROMPT telescopes at CTIO beginning 
3.0 hours after the the trigger in BVRI.

We detect the afterglow (Stamatikos et al., GCN 10034) in all filters.

Between 3.0 and 12.3 hours after the trigger, the afterglow faded with 
periods of rebrightening (1) beginning around 5 hours and peaking around 6 
hours, and (2) beginning around 8 hours and peaking around 9 hours.

Overall, if fitted with a power law, the afterglow faded with a power-law 
index of about -0.95 in BVR but only about -0.65 in I.  I - R brightened by 
about 0.45 mag over the course of 12 hours.

At 12.3 hours after the trigger, the afterglow's magnitude was R = 19.82 
+0.14 -0.12 (statistical) +/- 0.56 (systematic; calibrated to 115 USNO B1 
stars).

Skynet's most recent BVRI light curve, calibrated to USNO B1 and NOMAD 
stars, can be found here:

http://skynet.unc.edu/grb/grb091018.png


GRB_name: GRB091018A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10047
SUBJECT: GRB 091018: miniTAO/ANIR Observations
DATE:    09/10/20 05:47:04 GMT
FROM:    Takeo Minezaki at U.of Tokyo/Astro  <minezaki@mtk.ioa.s.u-tokyo.ac.jp>

K. Motohara, M. Konishi, K. Toshikawa, N. Mitani,
T. Minezaki, S. Koshida, D. Kato, Y. Yoshii$B!!(B(University of Tokyo),
Y. Ita (National Astronomical Observatory of Japan)
on behalf of the TAO project team:

We report the NIR imaging observation of GRB 091018 carried out
from October 19 2:09 to 2:57 (UTC), using NIR Camera ANIR
(Motohara et al. 2008, Proc. SPIE 7014, 70142T) mounted on
the 1.0m miniTAO telescope (Sako et al. 2008, Proc. SPIE7012, 70122T)
at the University of Tokyo Atacama Observatory on the summit
of Co. Chajnantor (5640m altitude) in the northern Chile.

The preliminary magnitudes (AB system) for the afterglow candidate
reported by Stamatikos et al. 2009 (GCN 10034) are ;

Y  = 18.98 +/- 0.14
J  = 19.40 +/- 0.19
H  = 18.93 +/- 0.17
Ks = 18.22 +/- 0.07

which are taken with the MKO filter system.


GRB_name: GRB091020A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10048
SUBJECT: GRB 091020: Swift detection of a burst with an optical afterglow
DATE:    09/10/20 21:47:36 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

J. L. Racusin (NASA/GSFC/ORAU), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), D. N. Burrows (PSU),
J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), C. Gronwall (PSU),
S. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU),
J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA),
N. P. M. Kuin (MSSL), W.B Landsman (GSFC), V. Mangano (INAF-IASFPA),
F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester),
K. L. Page (U Leicester), D. M. Palmer (LANL),
P. Romano (INAF-IASFPA), A. Rowlinson (U Leicester),
M. H. Siegel (PSU), E. Troja (NASA/GSFC/ORAU) and
T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:

At 21:36:44 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 091020 (trigger=373458).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 175.715, +50.972 which is 
   RA(J2000) = 11h 42m 52s
   Dec(J2000) = +50d 58' 19"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a bright peak
with a second much smaller peak at T+30 s, for a total duration 
of about 45 sec.  The peak count rate was ~5000 counts/sec (15-350 keV),
at ~2 sec after the trigger. 

The XRT began observing the field at 21:38:05.5 UT, 80.8 seconds after
the BAT trigger. XRT found a bright, fading, uncatalogued X-ray source located
at RA, Dec 175.7284, +50.9788 which is equivalent to:
   RA(J2000)  = 11h 42m 54.81s
   Dec(J2000) = +50d 58' 43.6"
with an uncertainty of 5.0 arcseconds (radius, 90% containment). This
location is 39 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. 

The initial flux in the 2.5 s image was 3.01e-09 erg cm^-2 s^-1 (0.2-10
keV). 

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)  = 11:42:55.18 = 175.72993
  DEC(J2000) = +50:58:41.9  = 50.97831
with a 90%-confidence error radius of about 0.74 arc sec. This position is 3.9
arc sec. from the center of the XRT error circle. The estimated magnitude is
15.73 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. L. Racusin (judith.racusin 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: GRB090926A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10049
SUBJECT: GRB 090926A: Late-time Gemini South Observations and Possible Jet Break
DATE:    09/10/20 22:10:04 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko@srl.caltech.edu>

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

We have imaged the field of the Fermi GRB090926A (Bissaldi et al., GCN
9933; Uehara et al., GCN 9934) with the Gemini Multi-Object Spectrograph
mounted on the 8-m Gemini South telescope.  Observations were taken in
the Sloan g', r', and i' filters beginning at 2:28 UT on 19 October 2009
(~ 22.9 d after the GBM trigger).

We detect a faint source in all filters at the location of the optical
afterglow (Haislip et al., GCN 9937, Gronwall et al., GCN 9938). Using
several unsaturated USNO-B objects in the field of view, along with the
filter transformations of Jordi, Grebel, and Ammon (2006 A&A 460, 339), we
measure a magnitude of r' ~ 23.7 for this source.  Along with its
relatively blue color (g' - i' ~ 0), the object appears marginally
extended, suggesting it is likely dominated by emission from the host
galaxy of GRB090926A.  We caution, however, that the host candidate is
partially blended with a nearby object (~ 1.5" in the SW direction, just
outside the optical and X-ray afterglow error circle) of comparable
magnitude, which likely affects the photometry.

Comparing with the last reported R-band detection (R ~ 21.5 at t ~ 11.1 d;
Haislip et al., GCN 10003), the optical decay must have significantly
steepened from previous measurements (power-law index alpha >~ 2.5).  A
similar steepening is hinted at in the latest XRT observations of this
source (see http://astro.berkeley.edu/~nat/swift/00020113/bat_xrt.jpg),
suggesting a possible jet break.  Using the measured redshift of z = 2.1
(Malesani et al., GCN 9942), the isotropic gamma-ray energy derived from
the Konus-Wind instrument (E_iso ~ 2e54 erg; Golenetskii et al., GCN
9959), and assuming expansion into a constant density medium (n ~ 1
cm^-3) with a gamma-ray efficiency ~ 20%, we infer an opening angle ~ 0.1
rad.  The collimation-corrected prompt energy release would therefore be
large, E ~ 1e52 erg.


GRB_name: GRB091020A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10050
SUBJECT: GRB 091020: Enhanced Swift-XRT position
DATE:    09/10/21 00:30:43 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 1088 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 091020, 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 = 175.73005, +50.97839 which is equivalent
to:

RA (J2000): 11h 42m 55.21s
Dec (J2000): +50d 58' 42.2"

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, MNRAS, 397, 1177).

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


GRB_name: GRB091020A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10051
SUBJECT: GRB 091020, Swift-BAT refined analysis
DATE:    09/10/21 01:28:59 GMT
FROM:    Hans Krimm at NASA-GSFC  <hans.krimm@nasa.gov>

D. M. Palmer (LANL), 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), A. M. Parsons (GSFC),
J. L. Racusin (NASA/GSFC/ORAU), 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+242 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 091020 (trigger #373458)
(Racusin, et al., GCN Circ. 10048).  The BAT ground-calculated position is
RA, Dec = 175.727, 50.977 deg which is
    RA(J2000)  =  11h 42m 54.4s
    Dec(J2000) = +50d 58' 36.6"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 43%.

The mask-weighted light curve began with a small hump at T-10 sec, rising
sharply to a peak at T+2 sec and decaying exponentially out to T+50 sec,
with a much smaller peak superimposed at T+30 sec. T90 (15-350 keV) is
34.6 +- 2.7 sec (estimated error including systematics).

The time-averaged spectrum from T-8.7 to T+38.3 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.53 +- 0.07.  The fluence in the 15-150 keV band is
3.7 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from
T+1.14 sec in the 15-150 keV band is 4.2 +- 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/373458/BA/


GRB_name: GRB091020A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10052
SUBJECT: GRB 091020: MASTER optical transient polarimetry 
DATE:    09/10/21 05:15:37 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc@observ.inetcomm.ru>

E. Gorbovskoy,D.Kuvshinov, V. Lipunov, V.Kornilov, D.Kuvshinov,
A.Belinski,  A. Krylov, N.Shatskiy, N.Tyurina, P.Balanutsa, V.V.Chazov,

Sternberg Astronomical Institute, Moscow State University

A. Tlatov, A.V. Parkhomenko, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

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

S.Yazev, K.Ivanov, N.M.Budnev
Irkutsk State University

V.Yurkov
Blagoveschensk Educational State University, Blagoveschensk

MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru, 2x400 
mm, 8 square degrees, 2x16Mpx Apogee CCD) located
at Kislovodsk  was pointed to the  GRB 091020 (Racusin et al., GCN 10048) 
by internet   3422 s after the GRB time. The 
large delay  was caused with   technical problems on site.

We see bright optical counterpart (~17.5 mag) on the firrst images at UVOT 
position.

We have 130  images with 180 sec synchronous exposition each and 19.5 
magnitude limit during ~4 hours in two polarization.

The power low decay with alpha ~= 1.3 during  2.5 hours is observed. 
This is the preliminary result.
The reduction is continued.



The message may be cited.

mailto: lipunov@sai.msu.ru


GRB_name: GRB091020A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10053
SUBJECT: GRB 091020: NOT spectroscopic redshift
DATE:    09/10/21 08:24:22 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@astro.ku.dk>

Dong Xu, Johan P.U. Fynbo (DARK/NBI), Nial R. Tanvir (Univ. Leicester), 
Jens Hjorth, Giorgos Leloudas, Daniele Malesani (DARK/NBI), Pall 
Jakobsson (Univ. Iceland), Paul A. Wilson (NOT and Univ. Oslo), Johannes 
Andersen (NBI and NOT), report on behalf of a larger collaboration:

We observed the optical afterglow of GRB 091020 (Racusin et al., GCN 
10048; Gorbovskoy et al., GCN 10052) with the Nordic Optical Telescope 
equipped with ALFOSC. We detect the afterglow with a magnitude R ~ 20, 
based on a nearby USNO star, with mean time Oct 21.220 UT (0.315 days 
after the GRB).

We secured low-resolution spectroscopy (30 min exposure), covering the 
wavelength range 3500-9100 AA, starting on Oct. 21.231 UT. Wavelength 
calibration was carried out using archival frames.

In a preliminary analysis we detect several absorption features, which 
we interpret as FeII 2344, 2374, 2382, Al III 1854, 1862, Mg II 2798 (Mg 
II 2803 is blended with the telluric A band), all at the common z = 
1.71. There is flux in the spectrum down to ~3800 AA, setting a firm 
upper limit z < 2.13 to the GRB redshift.


GRB_name: GRB091020A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10054
SUBJECT: GRB091020 Swift/UVOT observations
DATE:    09/10/21 11:18:58 GMT
FROM:    Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>

S. R. Oates (MSSL-UCL) and J. L. Racusin (NASA/GSFC/ORAU) report on  
behalf of the Swift/UVOT team:

The Swift/UVOT began observerving the field of GRB 091020 89 s
after the BAT trigger (Racusin et al., GCN Circ. 10048). We detect the
optical afterglow in all filters at the refined UVOT position
RA, Dec 175.730, +50.97833, which is

     RA  (J2000)  11:42:55.20
     Dec (J2000)  50:58:42.0

with an estimated uncertainty of 0.5 arcsec (radius, 90% confidence).
This position is consistent with the enhanced XRT position (Beardmore
et al., GCN 10050). The detection in the white, v, b and u filters and
the weak detection in the uvw1 filter is consistent with a redshift
z~1.7, which is consistent with redshift reported by NOT (Xu, et al.,  
GCN 10053).

Preliminary magnitudes and 3 sigma upper limits are reported below.

Filter    T_start(s) T_stop(s)  Exposure(s)   Mag  Err
------------------------------------------------------------------------
white       89        239        147          15.73 +/- 0.01
white       874       1024       147          17.27 +/- 0.03
v           799       819        19           16.40 +/- 0.15
b           1153      1173       19           17.27 +/- 0.15
u           707       727        19           17.06 +/- 0.16
uvw1        683       6929       490          20.29 +/- 0.35
uvm2        657       6723       490          > 20.29
uvw2        608       6314       303          > 20.27
-------------------------------------------------------------------------

The above magnitudes are not corrected for the Galactic extinction
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).


GRB_name: GRB091018A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10055
SUBJECT: GRB 091018: Swift XRT refined analysis
DATE:    09/10/21 11:55:55 GMT
FROM:    Giulia Stratta at ASDC  <giulia.stratta@gmail.com>

G. Stratta (ASDC) reports on behalf of the Swift-XRT team:

The Swift-XRT began observing GRB 091018 (trigger=373172) on
2009-10-18 at 20:49:20.5 UT, 60.9 seconds after the BAT trigger
(Stamatikos et al., GCN Circ. 7226). The data have been
taken in Windowed Timing (WT) mode from T + 67 s to T + 144 s
and in Photon Counting (PC) mode later on.

Enhanced position of the detected, bright X-ray afterglow
was given by Osborne et al. (GCN Circ. 10037)

The X-ray light curve from T + 67 s to T + 53.3 ks is well
fit by a broken power law model (chi^2 = 115 for 128 degrees
of freedom) with a temporal break at tb = T + (500 +/- 100) s and
decay indices alpha1 = -0.4 +/- 0.1 and alpha2 = -1.17 +/- 0.03
before and after the break, respectively.

The 0.3-10 keV spectrum from T + 156 s to T + 7.1 ks
is well fit by an absorbed power law (reduced chi2 of 1.0, with
50 degrees of freedom). The best fit photon index is 1.9 +/- 0.1,
with an hydrogen column density at the burst rest frame
(z=0.971, Hsiao-Wen Chen et al. GCN Circ.10038) of
NHz = (1.4 +/- 0.8)e21 cm^-2 in addition to the Galactic column
along the line of sight, that is NH = 2.8e20 cm^-2
(Kalberla et al. 2005). Errors are given at 90% confidence level.
The observed (unabsorbed) flux in the 0.3-10 keV band is
1.5(1.8)e-10 erg cm^-2 s^-1.

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


GRB_name: GRB091020A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10056
SUBJECT: GRB 091020: Swift-XRT refined analysis 
DATE:    09/10/21 14:08:47 GMT
FROM:    Andy Beardmore at U Leicester  <apb@star.le.ac.uk>

A. P. Beardmore, P. A. Evans (U. Leicester) and J. L. Racusin
(NASA/GSFC/ORAU) report on behalf of the Swift-XRT team:

We have analysed 13 ks of Swift-XRT data for GRB 091020 (Racusin et
al., GCN Circ. 10048), from 87 s to 29.6 ks after the BAT trigger
(#373458). The data comprise 350 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 10050).

The light curve shows an initial steep decay with an index of 3.7 +/-0.6,
breaking at T+130 s to a shallower decay of slope 0.90 +/- 0.03, with a
small flare superimposed at T+190s. A further break to a decay slope of
1.39 +/- 0.1 is apparent at T+6.6 ks.

The WT mode spectrum, from 87 s to 434 s after the trigger, can be fit
by an absorbed power-law with a photon index of 1.99 +/- 0.07. The
best-fitting absorption column is (6.08 +1.04 -0.99) x 10^21 cm^-2, at
a redshift of 1.71 (Xu et al., GCN Circ 10053), in addition to the
Galactic value of 1.4 x 10^20 cm^-2 (Kalberla et al. 2005). The PC
mode spectrum from 436 s to 7.3 ks (with an exposure time of 3.5 ks)
has a photon index of (2.15 +0.12 -0.11) and a best-fitting intrinsic
absorption column of (5.1 +1.6 -1.5) x 10^21 cm^-2. The counts to
observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from
this spectrum is 3.4 x 10^-11 (4.4 x 10^-11) erg cm^-2 count^-1.

If the light curve continues to decay at the same rate, the count rate
at T+24 hours will be 0.015 count s^-1, which corresponds to an
observed (unabsorbed) 0.3-10 keV flux of 4.8 x 10^-13 (6.3 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/00373458.

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


GRB_name: GRB091010A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10057
SUBJECT: Konus-Wind observations of GRB 091010
DATE:    09/10/21 14:12:00 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

The long GRB 091020 (Racusin et al., GCN 10048; Palmer et al., GCN Circ 10051)
triggered Konus-Wind at T0=77804.860s UT (21:36:44.860).

The burst light curve shows a smooth structure with a total
duration of ~40 s. The Konus-Wind light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB091020_T77804/

As observed by Konus-Wind the burst
had a fluence of (1.04  0.21)x10-5 erg/cm2,
and a 256-ms peak flux measured from T0 + 0.768s
of (1.2  0.2)x10-6 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).

The time-integrated spectrum of the burst (from T0 to T0+33.024 s)
is well fitted in the 20 keV - 2 MeV range by GRB (Band) model for which:
the low-energy photon index alpha = -0.93 (> -1.57),
the high energy photon index beta = -1.9(-0.8 / +0.2),
the peak energy Ep = 103(-68, +248) keV (chi2 = 62/60 dof).

All the quoted values are preliminary.
All the quoted errors are at the 90% confidence level.

Assuming z = 1.71 (Dong Xu et al., GCN 10053) and
a standard cosmology model with H_0 = 70 km/s/Mpc,
Omega_M = 0.27, Omega_Lambda = 0.73,
the isotropic energy release E_iso ~7.9x10^52 erg,
the peak luminosity (L_iso)_max ~2.5x10^52 erg/s,
and Ep_rest ~280 keV.


GRB_name: GRB091020A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10058
SUBJECT: GRB 091020: Lick observations
DATE:    09/10/21 14:24:31 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>

D. A. Perley (UC Berkeley) reports:

I observed the location of GRB 091020 (Racusin et al, GCN 10048) 
starting at UT 2009-10-21 12:30 using the Nickel 40-inch telescope at 
Lick Observatory.   A series of nine exposures in R-band were acquired, 
followed by five exposures in I-band and an additional sequence in 
R-band during morning twilight.  All exposures except for the first were 
of 180 seconds duration.

The afterglow is marginally detected in individual frames and 
well-detected in a combined stack.  Calibrating relative to five nearby 
SDSS standard stars transformed to R-band using the transformation 
equation of Lupton (2005), the estimated magnitude of the afterglow in 
the first R-band stack is:

R = 20.91 +/- 0.13 mag  (t_mid = 15.17 hr)

Additional follow-up is planned if weather permits.


GRB_name: GRB091020A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10059
SUBJECT: Konus-Wind observations of GRB 091020 (correction to GCN 10057)
DATE:    09/10/21 14:24:40 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

Dmitry Frederiks reports:

I made a mistake in the subject line of GCN 10057:
it should be "Konus-Wind observations of GRB 091020"
instead of "Konus-Wind observations of GRB 091010".

I apologize for the confusion.


GRB_name: GRB091020A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10060
SUBJECT: GRB 091020: Additional Lick observations
DATE:    09/10/22 14:22:00 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>

D. A. Perley (UC Berkeley) reports:

Further to observations the previous night (GCN 10058), I re-observed 
the afterglow of GRB 091020 between UT 2009-10-22 12:23 and 13:25 using 
the Nickel 40-inch telescope at Lick Observatory in a series of 
seventeen 180 second exposures (51 minutes total integration) in R-band.

The afterglow is detected in in the combined stack of all frames. 
Calibrating relative to the same SDSS standard stars as in GCN 10058, 
the estimated magnitude of the afterglow at this time is:

R = 21.81 +/- 0.23 mag  (t_mid = 39.29 hr)

The implied average decay index over the 24 hours since the previous 
observation is alpha=0.87.


GRB_name: GRB091018A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10061
SUBJECT: GRB 091018: Skynet/PROMPT Continued Observations of Fading
DATE:    09/10/23 14:36:01 GMT
FROM:    Aaron LaCluyze at U.North Carolina  <lacluyze@physics.unc.edu>

A. LaCluyze, D. Reichart, J. Haislip, K. Ivarsen, R. Egger, A. Foster, J. 
Moore, A. Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. 
Nysewander report:

Skynet has continued to observed the afterglow (Stamatikos et al., GCN 
10034) of GRB 091018 (Stamatikos et al., GCN 10034) with four of the 16" 
PROMPT telescopes at CTIO in BVRI.

After fading with a power-law index of about -0.95 in BVR between 3 and 12 
hours after the trigger (LaCluyze et al., GCN 10046), the afterglow faded 
with a steeper power-law index of about -1.3 in BR between 12 hours and 1.5 
days after the trigger, which is consistent with the findings of Cano et 
al. (GCN 10044).

However, between 1.5 days and 3.4 days after the trigger, the afterglow 
faded with a shallower power-law index of about -0.9 in R.

The I - R color of the afterglow, which brightened by about 0.45 mag 
between 3 and 12 hours after the trigger (LaCluyze et al., GCN 10046), has 
faded by about 0.1 +/- 0.3 mag between 12 hours and 3.4 days after the 
trigger, which is consistent with no additional color change, but the 
uncertainty is large.

At 3.4 days after the trigger, the afterglow's magnitude was R = 22.27 
+0.28 -0.23 (statistical) +/- 0.56 (systematic; calibrated to 115 USNO B1 
stars).

Skynet's most recent BVRI light curve, calibrated to USNO B1 and NOMAD 
stars, can be found here:

http://skynet.unc.edu/grb/grb091018.png

Continued observations with larger telescopes are encouraged.


GRB_name: GRB091024A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10062
SUBJECT: GRB 091024: Swift detection of a burst
DATE:    09/10/24 09:09:05 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

F. E. Marshall (NASA/GSFC), W. H. Baumgartner (GSFC/UMBC),
A. P. Beardmore (U Leicester), D. N. Burrows (PSU),
S. Campana (INAF-OAB), P. A. Evans (U Leicester),
S. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU),
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), B. Sbarufatti (INAF-IASFPA),
R. L. C. Starling (U Leicester) and T. N. Ukwatta (GSFC/GWU) report on
behalf of the Swift Team:

At 08:56:01 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 091024 (trigger=373674).  The BAT on-board calculated 
location is RA, Dec 339.207, +56.874 which is 
   RA(J2000) = 22h 36m 50s
   Dec(J2000) = +56d 52' 28"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a double-peaked
structure with the first peak at T=0 and a second smaller peak at T=40s 
with a total duration of about 50 sec.  The peak count rate
was ~5000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

Due to an observing constraint, Swift will not slew until 
T0+50.0 minutes. There will be no XRT or UVOT data until
this time. 

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: GRB091024A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10063
SUBJECT: GRB 091024: Faulkes Telescope North Afterglow Candidate
DATE:    09/10/24 09:43:48 GMT
FROM:    Carole Mundell at ARI, JMU,Liverpool  <cgm@astro.livjm.ac.uk>

C.G. Mundell, Z. Cano (Liverpool, JMU), C. Guidorzi (U. Ferrara),
I. A. Steele, A. Melandri, D. Bersier, S. Kobayashi, C.J. Mottram,
R.J. Smith (Liverpool, JMU), A. Gomboc, D. Kopac (U. Ljubljana),
P. O'Brien (U. Leicester) report:

"The 2-m Faulkes Telescope North robotically followed up GRB091024 (SWIFT
trigger 373674; Marshall et al. GCN 10062) 3.27 min after the GRB trigger
time. The automatic "detection mode" procedure detected an uncatalogued 
afterglow candidate at:

22:36:59.7   +56:53:23.4    (J2000) uncertainty 0.5"

with magnitude R = 18.1 +/-mag (vs USNOB1)

Observations and analysis are ongoing.

This message may be cited"


GRB_name: GRB091024A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10064
SUBJECT: GRB 091024: GRAS004 optical observations
DATE:    09/10/24 13:21:42 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 GRAS004 Epsilon 250 telescope with ST-8XE CCD 
at RAS Observatory Mayhill H06 (New Mexico, USA) for follow-up observations
of GRB091024 (D.Palmer et al. , GCN 10062). The observations were started 
on October 24, at 09:44 UTC (48 min after the burst) and stopped on October, 
at 09:58 UTC. One unfiltered 120 seconds image and one unfiltered 600 seconds image 
were taken. We detected a very dim uncatalogued optical afterglow object at the position
of RA 22h 36min 59s.68 and DEC +56o 53' 22".6   with respect to POSSII F
(J2000) which is in good correlation with Carole Mundell et al. observation 
(GCN 10063). Upper limit for our observations is >18.7 mag. Quoted upper 
limit has been derived using POSSII F and USNO-B1.0 field stars as reference.
                
Filter              Tmid(s)        Exp(s)     OA Mag (CR) USNO-B1.0
                
unfiltered         09:53:11        600         18.2+/-0.4


GRB_name: GRB091024A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10065
SUBJECT: GRB 091024 Gemini-North redshift
DATE:    09/10/24 13:49:15 GMT
FROM:    Nial Tanvir at IofA U.Cambridge  <nrt@ast.cam.ac.uk>

A. Cucchiara, D. Fox (PSU) & N. Tanvir (U. Leicester) report:

We observed the afterglow of GRB 091024 (Marshall et al. GCN 10062;
Mundell et al. GCN 10063) with the GMOS-N spectrograph on Gemini North
beginning at 10.43 UT.  The resultant spectrum, which spans 5925A to 10200A,
shows a strong continuum and well detected lines of CaII H & K, MgI (2853A)
at a common redshift of z=1.092.  Further analysis is ongoing.

We thank the Gemini-N support staff, in particular R. Pike, for
obtaining these observations.


GRB_name: GRB091024A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10066
SUBJECT: GRB 091024 : Faulkes Telescope North - Afterglow Confirmation
DATE:    09/10/24 14:03:43 GMT
FROM:    Zach Cano at ARI/John Moores Liverpool  <zec@astro.livjm.ac.uk>

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

The Faulkes Telescope North (Hawaii) continued observing the field of GRB
091024 (Swift trigger=373674, Marshall et al., GCN 10062).

We have detected an initial rise in the R & I LCs, peaking around To+600s
with 16.7 Rmag, which was followed by flaring activity that lasted
approximate 6ks.  After 6ks we estimate from our data a power-law decay
index alpha = 1.7 +/- 0.2.

As calibrated against nearby USNO objects, we find:

Filter   mag        merr      T-To (hr)
---------------------------------------
R       17.55       0.05      0.98
R       17.98       0.05      1.84
R       19.09       0.08      3.30

We also note the large amount of foreground extinction, E(B-V) = 0.98 mag
(Schlegel et al. 98), corresponding to AV=3.0 mag.


GRB_name: GRB091024A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10067
SUBJECT: GRB 091024: Xinglong TNT optical observation
DATE:    09/10/24 14:41:05 GMT
FROM:    L.P. Xin at NAOC  <xlp@bao.ac.cn>

H.Li, L.P. Xin, J. Wang, Y.L. Qiu, J.Y. Wei, W. K. Zheng, 
J.S. Deng, and C. Wu, J.Y. Hu on behalf of EAFON report:

We have observed GRB 091024 (Marshall et al. GCN 10062)
with Xinglong TNT telescope from  Oct. 24, 10:27:11 (UT),
1.3 hour after the burst. The optical afterglow 
(Cano et al. GCN 10066; Cucchiara et al. GCN 10065;
Mundell et al. GCN 10063) has been detected in our images.
The brightness is estimated to be about R~18.5 mag
derived from  USNO-A1.0 R magnitude, at the mean time
of 1.38 hour 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: GRB091024A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10069
SUBJECT: GRB 091024: Swift-XRT team refined analysis
DATE:    09/10/24 14:51:19 GMT
FROM:    Kim Page at U.of Leicester  <kpa@star.le.ac.uk>

K.L. Page (U. Leicester) and F.E. Marshall (NASA/GSFC) report on behalf of 
the Swift-XRT team:

Following an Earth-limb constraint, Swift-XRT began observing the field of 
GRB 091024 at 09:49:13, about 53 minutes after the BAT trigger. We detect 
a bright, uncatalogued X-ray source at a position of RA, Dec = 339.25167, 
56.88928, which is equivalent to

RA (J2000):   22 37 00.40
Dec (J2000):  56 53 21.4

with an uncertainty of 6 arcsec (radius, 90% confidence). This is 6.1 
arcsec from the optical afterglow candidate given by Mundell et al. (GCN 
Circ. 10063) and 6.0 arcsec from the position given by Nissinen & Hentunen 
(GCN Circ. 10064).

Only one orbit of data has been collected thus far (spanning 3.2-5.4 ks 
after the burst), but the source does appear to be fading, albeit with a 
relatively large uncertainty: alpha = 1.2 +/- 0.4.

The spectrum of the source, extracted from the 2.2 ks of Photon Counting 
mode data, can be fitted by an absorbed power-law with Gamma = 1.70 +/- 
0.17, the Galactic column of NH = 4.86 x 10^21 cm^-2 and an intrinsic 
column of (2.3 +1.0/-0.9) x 10^22 at a redshift of 1.092 (Cucchiara, Fox & 
Tanvir, GCN Circ. 10065). The observed (unabsorbed) flux over this time is 
7.23 x 10^-11 (1.15 x 10^-10) erg cm^-2 s^-1, corresponding to a counts to 
observed (unabsorbed) flux conversion of 7.5 x 10^-11 (1.2 x 10^-10) erg 
cm^-2 count^-1.

If the source continues to fade with alpha ~ 1.2, the predicted count rate 
at 24 hours will be 0.034 count s^-1, corresponding to an observed 
(unabsorbed) flux of 2.6x10^-12 (4.1x10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at 
http://www.swift.ac.uk/xrt_products/00373674.

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


GRB_name: GRB091024A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10070
SUBJECT: GRB 091024:  Fermi GBM Observations
DATE:    09/10/24 17:12:37 GMT
FROM:    Valerie Connaughton at MSFC  <valerie@nasa.gov>

Elisabetta Bissaldi (MPE) and Valerie Connaughton (UAH)
report on behalf of the Fermi GBM Team:


"At 08:55:58.47 UT on 24 October 2009, the Fermi Gamma-Ray Burst Monitor
(GBM) triggered and located GRB 091024 (trigger 278067360 / 091024372),
which was also detected by the Swift-BAT (Marshall et al. 2009, GCN 10062).
The GBM on-ground location is consistent with the Swift position. At
09:06:29.36, GBM triggered on what appears to be the continuation of this
burst (trigger 278067991 / 091024380).   The GBM on-ground location for 
this
second trigger is also consistent with the Swift position for GRB 091024.

The angle from the Fermi LAT boresight at the time of the
first trigger is 97 degrees and at the time of the second trigger
it is 14 degrees.  Furthermore, at 09:12:14.28, the Fermi spacecraft 
executed
a maneuver to place the burst near the center of the Large Area Telescope
(LAT) field-of-view and observe this region for 5 hours subject to
Earth angle constraints.

The first emission episode appears to last about 50 s, with 2 peaks 
separated
by a few seconds.  A brighter emission periods starts at the time of the 
2nd
trigger, 630 s later, and persists for at least 400 s.   This second 
emission period
shows an initial pulse (at 630 s) lasting about 40 s, followed by a 
multi-peaked
episode starting 210 s later (840 s from the first trigger) and lasting 
over 100 s. 
There is evidence for lower-level emission beyond this time.  The Fermi
spacecraft entered the South Atlantic Anomaly 2200 s after trigger 
091024380,
by which time there was no obvious emission in GBM.

In a first, preliminary analysis, we have fit time-integrated spectra 
for each of the
3 main emission blocks.  The first trigger appears to have an EPeak of 
about
400 keV;  the first peak of the second trigger is quite weak and best 
fit using
a power-law of index around -1.5;  the long and brighter emission period of
the second trigger has an EPeak of around 300 keV.  Detailed spectral
analyses and fluence values will be given in a future circular.

The POC for this burst is Elisabetta Bissaldi (ebs@mpe.mpg.de).


GRB_name: GRB091024A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10072
SUBJECT: GRB 091024: Swift-BAT refined analysis
DATE:    09/10/24 17:40:10 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), F. E. Marshall (NASA/GSFC),
D. M. Palmer (LANL), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC),
T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+483 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 091024 (trigger #373674)
(Mashall, et al., GCN Circ. 10062).  The BAT ground-calculated position is
RA, Dec = 339.240, 56.885 deg, which is 
   RA(J2000)  =  22h 36m 57.6s 
   Dec(J2000) = +56d 53' 07.8" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 39%.
 
The mask-weighted light curve shows two slightly overlapping FRED peaks.
The first starts at ~T-20 sec, peaks at ~T+2 sec.  The second peaks at ~T+42 sec
and long-term low-level emission extends out to ~T+400 sec.
T90 (15-350 keV) is 109.8 +- 16.7 sec (estimated error including systematics).
 
The time-averaged spectrum from T-15.2 to T+135.8 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.20 +- 0.08.  The fluence in the 15-150 keV band is 6.1 +- 0.3 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T-0.23 sec in the 15-150 keV band
is 2.0 +- 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/373674/BA/


GRB_name: GRB091024A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10073
SUBJECT: GRB091024: VRcIc Afterglow Observations
DATE:    09/10/24 20:09:04 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 obtained photometry of the GRB091024 afterglow reported by Mundell et
al. (GCN 10063) using the Sonoita Research Observatory (SRO) 35cm telescope
in southern Arizona, utilizing an automatic VOevent trigger.  The Rc-band
exposures began about 9 minutes after the burst and continued for approximately
one hour.  Ten Rc-band, nine V-band, and one Ic-band exposures were acquired.

Photometry, assuming that USNO-B1.0 1468-0448363 (RA: 22:36:44.11 ,
Dec: +56:52:42.6) has the following magnitudes: V=13.46, R=12.93, I=12.71

UT(mid)   delT   exp   mag     err  filter
09.1122    642   180  17.177  0.030   Rc
09.1667    839   180  17.510  0.037   Rc
09.2192   1028   180  17.827  0.049   Rc
09.2722   1218   180  17.993  0.044   Rc
09.3247   1407   180  18.136  0.056   Rc
09.4123   1723   300  18.008  0.046   Rc
09.5000   2038   300  17.764  0.045   Rc
09.5859   2348   300  17.737  0.033   Rc
09.6717   2657   300  17.665  0.037   Rc
09.7575   2965   300  17.776  0.045   Rc
09.8609   3338   300  19.029  0.111   V
09.9486   3653   300  19.267  0.120   V
10.0348   3964   300  19.290  0.132   V
10.1206   4273   300  19.320  0.126   V
10.2064   4581   300  19.237  0.091   V
10.2923   4891   300  19.345  0.151   V
10.4642   5510   300  19.163  0.107   V
10.5500   5818   300  19.293  0.123   V
10.6359   6128   300  19.350  0.163   V
10.8439   6877   180  17.550  0.074   Ic


Where delT is the time in seconds from the burst (Marshall et al., GCN
10062), and the exposure is in seconds.

Astrometry from the Rc frames, using UCAC3, yields a precise position of
22:36:59.68 +56:53:23.3 J2000 (+/- 100mas).  A full BVRcIc calibration
is in the Sonoita queue and will be released when photometric conditions
permit.

The AAVSO thanks the Curry Foundation for its support of the AAVSO
International High Energy Network.


GRB_name: GRB091024A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10074
SUBJECT: GRB 091024: Super-LOTIS early observations
DATE:    09/10/25 02:37:28 GMT
FROM:    Adria C. Updike at Clemson U  <aupdike@clemson.edu>

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

The 0.6m Super-LOTIS telescope located at Kitt Peak National Observatory
began observing the field of GRB 091024 (Marshall et al., GCN 10062) 58
seconds after the BAT trigger under good conditions.  We detect the
afterglow (Mundell et al., GCN 10063) in early stacked 20s exposures and
individual 60s exposures beginning 5 min after the trigger.  At 3.62 min
after the trigger, we measure the magnitude to be R = 17.7 +/- 0.1
relative to field stars and the USNO B1.0 catalog.  Observations continued
for 36 minutes.


GRB_name: GRB091024A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10075
SUBJECT: GRB 091024: KAIT optical afterglow observations
DATE:    09/10/25 02:54:09 GMT
FROM:    Ryan Chornock at UC Berkeley  <chornock@astro.berkeley.edu>

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

The Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory automatically
responded to the Swift BAT trigger for GRB 091024 (Marshall et al., GCN 10062)
with a sequence of observations starting 82 s after the BAT trigger.  The
afterglow is not initially detected.  Our first detection of the optical
afterglow (Mundell et al., GCN 10063) is in a 20 s I band observation starting
at 08:58:45 UT.  The KAIT position is

(J2000) 22:36:59.64  +56:53:24.0

which is consistent the positions reported by Mundell et al. (GCN 10063) and
Henden et al. (GCN 10073).  The optical afterglow is thereafter detected in a
sequence of V, I, and unfiltered images as it rose to a peak at an unfiltered
magnitude of 16.2 (preliminarily calibrated to USNO-B1) at t=404s and then
declined to mag 17.0 at t=988s, similar to the behavior described by Cano et al.
(GCN 10066).  After this time observations ceased due to a pointing limit.


GRB_name: GRB091020A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10076
SUBJECT: GRB 091020: Early TLS Multicolor detections, red afterglow
DATE:    09/10/25 05:58:15 GMT
FROM:    Alexander Kann at TLS Tautenburg  <kann@tls-tautenburg.de>

D. A. Kann, U. Laux, M. Roeder & H. Meusinger (TLS Tautenburg) report:

We observed the afterglow of the Swift GRB 091020 (Racusin et al., GCN 
10048) with the 1.34m Schmidt telescope of the Thueringer Landessternwarte 
Tautenburg, Germany, as soon as it had risen to an airmass of

2.2, starting 0.167 days after the GRB. We obtained 3 x 300 sec images in 
Z, Ic, Rc, V and B each. We detect the afterglow in all single images.

As a comparison star, we use the SDSS star at:

RA (J2000) =    11:42:49.2 (175.7050129)
Dec. (J2000) = +51:00:52.42 (+51.01456163)

For this star, using the transformation equations of Lupton (2005) (taking 
the mean of the two transformation equations each), and transforming the 
z' value to Vega mags following Fukugita (1995), we derive the

magnitudes:

B =  19.109
V =  17.740
Rc = 16.759
Ic = 15.927
Z =  15.563

We derive the following afterglow magnitudes:

dt  Filter mag dmag
____________________________________
0.166947 Z 18.17 0.13
0.170987 Z 18.10 0.13
0.175038 Z 18.16 0.13
0.179181 Ic 18.45 0.06
0.183221 Ic 18.30 0.05
0.187260 Ic 18.32 0.05
0.191404 Rc 19.43 0.04
0.195444 Rc 19.40 0.04
0.199483 Rc 19.40 0.04
0.203627 V 19.90 0.10
0.207666 V 20.00 0.10
0.211706 V 20.06 0.10
0.215849 B 20.78 0.10
0.219889 B 20.71 0.08
0.223928 B 20.72 0.08

Using further reported magnitudes (Oates et al., GCN 10054; Gorbovskoy et 
al., GCN 10052, Xu et al., GCN 10053, Perley, GCN 10058, GCN 10060), we 
find that the Rc band light curve is very well described by a

single power-law decay with alpha = 1.12 +/- 0.06, B and V light curves 
agree with an achromatic light curve evolution. We find a red afterglow 
with spectral slope beta ~ 2, and note that the Ic - Z color is

very blue, this may be due to a filter mismatch between the SDSS z' filter 
and our Z filter.

This message may be cited.


GRB_name: GRB091024A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10077
SUBJECT: GRB 091024: TLS Upper Limit
DATE:    09/10/25 05:59:03 GMT
FROM:    Alexander Kann at TLS Tautenburg  <kann@tls-tautenburg.de>

D. A. Kann, and U. Laux (TLS Tautenburg) report:

We observed the afterglow of the ultra-long Swift/GBM GRB 091024 (Marshall 
et al., GCN 10062, Mundell et al., GCN 10063, Bissaldi & Connaughton, GCN 
10070) with the 1.34m Schmidt telescope of the Thueringer

Landessternwarte Tautenburg, Germany, 0.6 days after the GRB. We obtained 
6 x 600 sec images in Rc.

As a comparison star, we use the USNOB1.0 star at:

RA (J2000) =    22:37:31.11
Dec. (J2000) = +56:59:26.23

which has R2 = 17.78 mag. This was one of the rare non-blended stars that 
was bright enough to be detected in the catalog.

At the afterglow position, we do not detect any source which is not 
detected anyway in the DSS2 red plate. We place the following 2 sigma 
upper limit on the afterglow:

dt  Filter UL
____________________________________
0.602309 Rc 21.0

and note that the true upper limit may be less deep due to crowding (the 
afterglow pretty much conincides with a ~20th mag object detected in the 
DSS).

No further observations are planned.

This message may be cited.


GRB_name: GRB091024A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10078
SUBJECT: GRB091024 Swift/UVOT Upper Limits
DATE:    09/10/25 11:05:38 GMT
FROM:    Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>

S. R. Oates (MSSL-UCL) and F. E. Marshall (NASA/GSFC) report on behalf  
of the Swift/UVOT team:

The Swift/UVOT began observerving the field of GRB 091024 ~3ks
after the BAT trigger (Marshall et al., GCN Circ. 10062). No
optical afterglow is detected in the UVOT exposures at
the refined position of the X-ray afterglow (Page et al.,
GCN Circ. 10069) and the position reported by Faulkes
Telescope North (Mundell., et al., GCN Circ. 10063).

The 3 sigma upper limits for the b, u, uvw2 and summed uvw1
exposures are reported below.

Filter    T_start(s) T_stop(s)  Exposure(s)      3sigma Upper Limit
-------------------------------------------------------------------
b           45981      45984       3               > 17.31
u           32984      33055       70              > 19.03
uvw1        26617      38935       1283            > 20.37
uvw2        3151       3161        10              > 17.28
-------------------------------------------------------------------

The above magnitudes are not corrected for the Galactic extinction
corresponding to a significant reddening of E_{B-V} = 0.99 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).


GRB_name: GRB091020A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10080
SUBJECT: GRB 091020 : Xinglong TNT upper limit
DATE:    09/10/26 12:31:47 GMT
FROM:    L.P. Xin at NAOC  <xlp@bao.ac.cn>

L.P. Xin, X.F. Wang, J. Wang, Y.L. Qiu, J.Y. Wei, 
W.K. Zheng, J.S. Deng, and C. Wu, J.Y. Hu 
on behalf of EAFON report:

We observed the optical afterglow of GRB 091020 
(e.g. Racusin et al., GCN 10048; Gorbovskoy et al., 
GCN 10052; Perley GCN 10060) with Xinglong TNT 
telescope from  Oct. 22, 20:27:52(UT),1.952 days 
after the burst. The optical afterglow (Gorbovskoy 
et al., GCN 10052; Perley GCN 10060) was not detected 
in our combined image with a duration of 7*600 sec.
The upper limit is estimated to be R~21.4 mag 
from  USNO-B1.0 R2 magnitude, at the mean time of 
1.974 days since the trigger.

This message may be cited.

For more information about Xinglong GRBs Follow-up 
observations, please visit the web-site:
http://www.xinglong-naoc.org/grb/


GRB_name: GRB091026A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10081
SUBJECT: GRB 091026: Swift detection of a Gamma Ray Burst
DATE:    09/10/26 13:23:09 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

C. B. Markwardt (CRESST/GSFC/UMD), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), D. N. Burrows (PSU),
P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), D. Grupe (PSU),
C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC),
E. A. Hoversten (PSU), J. A. Kennea (PSU), V. Mangano (INAF-IASFPA),
J. Mao (INAF-OAB), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester), D. M. Palmer (LANL),
P. Romano (INAF-IASFPA), P. Roming (PSU), B. Sbarufatti (INAF-IASFPA),
M. H. Siegel (PSU) and M. Stamatikos (OSU/NASA/GSFC) report on behalf
of the Swift Team:

At 13:11:30 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 091026 (trigger=373871).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 276.583, -86.121 which is 
   RA(J2000)  =  18h 26m 20s
   Dec(J2000) = -86d 07' 16"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a FRED pulse
with a duration of about 20 sec.  The peak count rate
was ~2500 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 13:12:48.9 UT, 78.7 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 276.59337, -86.11056 which
is equivalent to:
   RA(J2000)  = 18h 26m 22.41s
   Dec(J2000) = -86d 06' 38.0"
with an uncertainty of 4.0 arcseconds (radius, 90% containment). This
location is 37 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 (8.36e+20
cm^-2, Kalberla et al. 2005), with an excess column of 3.6
(+2.72/-2.29) x 10^21 cm^-2 (90% confidence). 

The initial flux in the 2.5 s image was 3.42e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 87 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
0.13. 

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: GRB091026A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10082
SUBJECT: GRB 091026: Updated Swift-XRT position
DATE:    09/10/26 14:10:46 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

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

Using the full set of promptly downlinked XRT event mode data totalling 
760 s in Photon Counting mode, and 2 UVOT images, we find an enhanced 
XRT position for GRB 091026 (Markwardt et al. GCN Circ. 10081) of RA, 
Dec = 276.5725, -86.1115 (degrees) which is equivalent to:

RA  (J2000) = 18 26 17.41
DEC (J2000) = -86 06 41.5

with an uncertainty of 2.1 arcsec (radius, 90% containment).

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


GRB_name: GRB091024A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10083
SUBJECT: Konus-Wind and Konus-RF observations of GRB 091024
DATE:    09/10/26 17:18:48 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, and D. Svinkin on behalf of
the Konus-Wind and Konus-RF teams, and
T. Cline on behalf of the Konus-Wind team, report:

The long GRB 091024 (Swift-BAT trigger #373674: Marshall et al. GCN 
10062, Sakamoto et al. GCN 10072) was observed by Konus-Wind in the 
waiting mode. The emission was detected in all three Konus-Wind energy 
bands: G1 (18-70  keV), G2 (70-360 keV) and G3 (360-1360 keV) with high 
S/N.

The burst light curve shows three pulses: the first pulse starts at 
~T0-10 s and has a duration of ~90 s, the second starts at ~T0+600 s and 
has a duration of ~100 s, and the most intense third pulse starts at 
T0+840 s and has a duration of ~400 s; there is a low-level emission 
between the first and second pulses.

The most intense part of the third pulse was also detected by Konus-RF, 
while Coronas-F was exiting the SAA.

The GBM localizations suggest a common origin of these events (Bissaldi 
& Connaughton, GCN 10070). Both the K-W light curve and the K-W ecliptic 
latitude response confirms this suggestion. So, we believe all these 
pulses belong to the extremely long burst, GRB 091024, which has a total 
duration of ~1200 s. Hence, some optical observations of this burst were 
performed during the most intense part of the prompt emission, but no 
bright optical flares have been reported.

Modeling of the K-W 3-channel spectra by
a power law with exponential cutoff model:
dN/dE ~ E^(-alpha)*exp(-E*(2-alpha)/Ep)
yields the following parameters:
--------------------------------------------------
       Tstart    Tstop       alpha      Ep (keV)
--------------------------------------------------
P1     -7          80   -1.1+/-0.2    500+/-160
P2    606         703   -1.6+/-0.2    200+/-120
P3    835        1194   -1.4+/-0.2    230+/-50
Total  -7        1194   -1.5+/-0.4    280+/-120
--------------------------------------------------
Tstart, Tstop - seconds since the BAT trigger time


As observed by Konus-Wind, the burst had a fluence of (1.13 +/- 
0.12)x10^-4 erg/cm2 (in the 20 - 1300 keV energy range).

Assuming z = 1.092 (Cucchiara, Fox & Tanvir, GCN 10065) and a standard 
cosmology model with H_0 = 70 km/s/Mpc, Omega_M=0.27, Omega_\Lambda = 
0.7, the isotropic energy release E_iso ~3.2x10^53 erg.

All the quoted errors are estimated at the 1 sigma confidence level.

The K-W light curve of this burst is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB091024/


GRB_name: GRB091026A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10084
SUBJECT: GRB 091026: Enhanced Swift-XRT position
DATE:    09/10/26 18:59:15 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 512 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 091026, 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 = 276.57076, -86.11163 which is equivalent
to:

RA (J2000): 18h 26m 16.98s
Dec (J2000): -86d 06' 41.9"

with an uncertainty of 1.9 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, MNRAS, 397, 1177).

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


GRB_name: GRB091026A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  10085
SUBJECT: GRB 091026: Swift-XRT refined analysis
DATE:    09/10/26 20:03:52 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

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

We have analysed 2.2 ks of XRT data for GRB 091026 (Markwardt et al. GCN
Circ. 10081), from 85 s to 6.8 ks after the BAT trigger. The data
comprise 326 s in Windowed Timing (WT) mode with the remainder in Photon
Counting (PC) mode. The enhanced XRT position for this burst was given
by Evans et al. (GCN. Circ 10084).

The light curve shows three flares in the first snapshot, with peaks
at T0+180 s, T0+340 s and T0+~890 s. The orbital gap interrupts the
final flare, making its peak time somewhat uncertain. If these flares
are disregarded (i.e. fitting only the data from 85 s to 150 s and 2 ks to
6.8 ks), the underlying light curve can be modelled with an initial
power-law decay with an index of alpha=3.40 (+0.31, -0.26), followed by
a break at T+149 s to an alpha of 0.98 (+0.07, -1.7).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.97 (+/-0.08). The
best-fitting absorption column is 2.93 (+0.28, -0.27) x 10^21 cm^-2, in
excess of the Galactic value of 8.4 x 10^20 cm^-2 (Kalberla et al.
2005). The PC mode spectrum has a photon index of 2.01 (+0.18, -0.17)
and a best-fitting absorption column of 3.5 (+0.7, -0.6) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 4.6 x 10^-11 (7.6 x 10^-11) erg cm^-2
count^-1.

If the light curve continues to decay with a power-law decay index of
0.98, the count rate at T+24 hours will be 0.018 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.3 x
10^-13 (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/00373871.

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


