# GCN_circulars

GRB_name: GRB150428A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17774
SUBJECT: GRB 150428A: Swift-BAT refined analysis
DATE:    15/04/28 12:49:41 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), 
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), 
C. B. Markwardt (GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), 
T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (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 150428A (trigger #639275) 
(Page, et al., GCN Circ. 17765).  The BAT ground-calculated position is 
RA, Dec = 188.539, 6.967 deg which is 
  RA(J2000) =   12h 34m 09.3s 
  Dec(J2000) = +06d 58' 00.8â€ 
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). 
The partial coding was 16%. 

The mask-weighted light curve shows a multi-peaked structure that starts at 
~ T-40 sec and ends at ~ T+60 sec.  T90 (15-350 keV) is 53.2 +- 15.1 sec 
(estimated error including systematics). 

The time-averaged spectrum from T-39.0 to T+38.6 sec is best fit by a simple 
power-law model. The power law index of the time-averaged spectrum is 1.28 +- 0.09. 
The fluence in the 15-150 keV band is 6.3 +- 0.3 x 10^-6 erg/cm2.  The 1-sec peak 
photon flux measured from T+17.4 sec in the 15-150 keV band is 3.0 +- 0.5 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/639275/BA/


GRB_name: GRB150428C
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17775
SUBJECT: GRB 150428C: Tiled Swift observations
DATE:    15/04/28 13:01:17 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift has initiated a series of observations, tiled on the sky, of the
MAXI GRB 150428C. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00043

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. The probability of finding
serendipitous sources, unrelated to the MAXI event is high: any X-ray source
considered to be a probable afterglow candidate will be reported via a GCN Circular
after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

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


GRB_name: GRB150428B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17776
SUBJECT: GRB 150428B: Swift-BAT refined analysis 
DATE:    15/04/28 13:45:43 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), 
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), 
C. B. Markwardt (GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), 
T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (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 150428B (trigger #639278) 
(Page, et al., GCN Circ. 17766).   The BAT ground-calculated position is 
RA, Dec = 292.661, 4.114 deg which is 
 RA(J2000)  =  19h 30m 38.8s 
 Dec(J2000) = +04d 06' 52.2â€ 
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).  
The partial coding was 40%. 

The mask-weighted light curve shows three peaks.  The first peak starts at T-40 sec, 
peaks at T-25 sec and ends at T-20 sec.  The second peak starts at T-15 sec, peaks 
at T+5 sec and ends at T+50 sec.  And the third peak starts at T+55 sec, peaks at T+65 sec 
and ends at T+120 sec.  T90 (15-350 keV) is 130.9 +- 15.6 sec 
(estimated error including systematics).  

The time-averaged spectrum from T-40.1 to T+121.7 sec is best fit by a power law 
with an exponential cutoff.  This fit gives a photon index 1.0 +- 0.5, and Epeak 
of 55 +- 10 keV (chi squared 37.44 for 56 d.o.f.).  For this model the total 
fluence in the 15-150 keV band is 3.7 +- 0.3 x 10^-6 erg/cm2 and the 1-sec peak flux 
measured from T+1.36 sec in the 15-150 keV band is 1.5 +- 0.3 ph/cm2/sec.  A fit 
to a simple power law gives a photon index of 1.87 +- 0.10 
(chi squared 49.44 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/639278/BA/


GRB_name: GRB150428A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17777
SUBJECT: GRB 150428A: Swift-XRT refined Analysis
DATE:    15/04/28 14:13:12 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:

We have analysed 1.3 ks of XRT data for GRB 150428A (Page et al. GCN
Circ. 17765), from 160 s to 32.5 ks after the  BAT trigger. The data
comprise 8 s in Windowed Timing (WT) mode (taken while Swift was
slewing), with the remainder in Photon Counting (PC) mode. The enhanced
XRT position for this burst was given by Osborne et al. (GCN Circ.
17768).

The light curve can be modelled with a power-law decay with a decay
index of alpha=0.75 (+/-0.05).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.0 (+0.4, -0.3). The
best-fitting absorption column is  5.3 (+2.4, -1.9) x 10^21 cm^-2, in
excess of the Galactic value of 1.6 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 4.1 x 10^-11 (6.8 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      5.3 (+2.4, -1.9) x 10^21 cm^-2
Galactic foreground: 1.6 x 10^20 cm^-2
Excess significance: 4.4 sigma
Photon index:      2.0 (+0.4, -0.3)

If the light curve continues to decay with a power-law decay index of
0.75, the count rate at T+24 hours will be 0.028 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x
10^-12 (1.9 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/00639275.

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


GRB_name: GRB150428A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17778
SUBJECT: GRB 150428A: MASTER-net early optical observation 
DATE:    15/04/28 15:19:00 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

D.Buckley, S. Potter, A.Kniazev, M.Kotze
South African Astronomical Observatory

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

K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk
Irkutsk State University

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

V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov
Blagoveschensk Educational State University, Blagoveschensk

V.Krushinski, I.Zalozhnih,  A. Popov
Ural Federal University, Kourovka

Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

Claudio Mallamaci, Carlos Lopez and Federico Podest
Observatorio Astronomico Felix Aguilar (OAFA)


MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in SAAO was pointed to the  GRB150428A (Page et al, GCN 17765) 28 
sec after notice time and 90 sec after trigger time at 2015-04-28 01:32:10 
UT in two polarizations. On our first  single and coadd images  we haven't 
found optical transient  within SWIFT error-box . The observations made on 
a high zenith distance  ~ 80 d.
We obtain a followin upper limits:



Date start  T_s-T_tr   T_m-T_trig     Expt.  Limit Coadd
                       (mean_time)
01:32:10.9    90          100          20      16.0   no
01:32:43.2   122          132          20      16.0   no
01:33:14.7   153          168          30      16.4   no
01:33:14.7   153          224         120      17.0    3
01:33:14.7   153          583         770      18.5    9

Also, we can not confirm  Danish 1.56m OT (Andersen et. al GCN 17771), 
because they do not see it on our images with upper limits specified 
above.


The message may be cited.


GRB_name: GRB150428B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17780
SUBJECT: GRB 150428B: MASTER-net prompt optical observation
DATE:    15/04/28 15:33:45 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

D.Buckley, S. Potter, A.Kniazev, M.Kotze
South African Astronomical Observatory

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

K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk
Irkutsk State University

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

V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov
Blagoveschensk Educational State University, Blagoveschensk

V.Krushinski, I.Zalozhnih,  A. Popov
Ural Federal University, Kourovka

Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

Claudio Mallamaci, Carlos Lopez and Federico Podest
Observatorio Astronomico Felix Aguilar (OAFA)

MASTER II  robotic telescope (MASTER-SAAO: http://observ.pereplet.ru) 
located in SAAO was pointed to the  GRB150428B 24 sec after notice time 
and 59 sec after trigger time at 2015-04-28 03:13:03 UT in two 
polarizations. On our first (10s exposure)  set we haven't found optical 
transient  within SWIFT BAT (Page et. al GCN 17766) and XRT (Beardmore et 
al. GCN 17773) error-boxes .
We have 3x2 images during Gamma Ray activity (see Page et al., GCN 17777) 
in two polarizations.
So our observations is prompt observations.
We obtain a followin upper limits on single and coadd images:

Date start  T_start -T_trig  T_mid-T_trig  Expt.  Limit Coadd

03:13:03.3        59             64         10    16.5   no
03:13:03.3        59             97         50    17.4    3
03:13:03.3        59            529        810    19.3   12


Data analysis was hampered by a high density of stars in the error box. 
XRT position covered by  bright (~15m) star USNO B1 0941-0468603.



The message may be cited.


GRB_name: GRB150428B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17781
SUBJECT: GRB 150428B: Swift-XRT refined Analysis
DATE:    15/04/28 15:37:03 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), J.A. Kennea (PSU), B.
Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), P.A. Evans (U.
Leicester), A. Amaral-Rogers (U. Leicester), J.P. Osborne (U.
Leicester), M. de Pasquale (INAF-IASFPA) and K.L. Page report on behalf
of the Swift-XRT team:

We have analysed 8.3 ks of XRT data for GRB 150428B (Page et al. GCN
Circ. 17766), from 100 s to 34.4 ks after the  BAT trigger. The data
comprise 187 s in Windowed Timing (WT) mode (the first 6 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Beardmore
et al. (GCN Circ. 17773).

The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=2.31 (+0.16, -0.20). At T+170 s  the decay
steepens to an alpha of 4.92 (+0.15, -0.16) before breaking again at
T+618 s to a final decay with index alpha=0.29 (+/-0.07).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.93 (+0.06, -0.05). The
best-fitting absorption column is  3.51 (+0.28, -0.25) x 10^21 cm^-2,
consistent with the Galactic value of 3.3 x 10^21 cm^-2 (Willingale et
al. 2013). The PC mode spectrum has a photon index of 1.90 (+0.16,
-0.08) and a best-fitting absorption column consistent with the
Galactic value. The counts to observed (unabsorbed) 0.3-10 keV flux
conversion factor deduced from this spectrum  is 3.9 x 10^-11 (5.6 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      3.3 (+0.3, -0.0) x 10^21 cm^-2
Galactic foreground: 3.3 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.90 (+0.16, -0.08)

If the light curve continues to decay with a power-law decay index of
0.29, the count rate at T+24 hours will be 0.027 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x
10^-12 (1.5 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/00639278.

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


GRB_name: GRB150428C
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17782
SUBJECT: GRB 150428C: MASTER-net automatic  optical inspection 
DATE:    15/04/28 17:12:31 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov
Blagoveschensk Educational State University, Blagoveschensk

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

D.Buckley, S. Potter, A.Kniazev, M.Kotze
South African Astronomical Observatory

K.Ivanov, S.A.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk
Irkutsk State University

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

V.Krushinski, I.Zalozhnih,  A. Popov
Ural Federal University, Kourovka

Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

Carlos Lopez, Claudio Mallamaci and Federico Podest
Observatorio Astronomico Felix Aguilar (OAFA)

MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in Blagoveschensk was pointed to the  GRB150428C 12184 sec after 
notice time (after sun set) and 15390 sec after trigger time at 
2015-04-28 12:40:45 UT.

We did not find OT brighter then 17.4 mag .

The message may be cited.


GRB_name: GRB150426A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17783
SUBJECT: GRB 150426A: Fermi GBM detection
DATE:    15/04/28 18:33:49 GMT
FROM:    Binbin Zhang at UAH  <binbin.zhang@uah.edu>

Bin-Bin Zhang (UAH) report on behalf of the Fermi GBM team:

"At 14:15:31.22 on April 26 2015, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 150426A (trigger 451750534/150426594).
The GBM on-ground location, using the Fermi GBM trigger
data, is RA = 17.6, Dec = -30.2 with an uncertainty of 1.5
degrees (radius, 1-sigma containment,statistical
only; there is additionally a systematic error which is
currently estimated to be 2 to 3 degrees). The angle of the
burst direction to the Fermi LAT boresight is 136 degrees.


The GBM light curve consists of multiple peaks with a duration (T90)
of about 23 s (50-300 keV). The time-averaged spectrum from T0+0s to
T0+23 s is well fit by a BAND function with Epeak = 109.9 +/- 10.6 keV,
alpha = -1.0 +/- 0.1 and Beta = -2.3 +/- 0.1. The event fluence (10-1000 keV)
in this time interval is (1.15 +/- 0.04)E-05 erg/cm^2. The 1.0-sec
peak photon flux measured starting from T0+13.8 s in the 10-1000 keV
band is 22.1 +/- 0.7 ph/s/cm^2.


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


GRB_name: GRB150413A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17784
SUBJECT: GRB 150413A: CrAO optical observations
DATE:    15/04/28 19:47:55 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

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

We observed the field of the GRB 150413A (Markwardt  et al., GCN 17688) 
  with AZT-11 telescope of CrAO observatory starting on Apr. 13 (UT) 
17:39:02. Several images were take in R-filter. The afterglow   (Ivanov 
et al., GCN 17689) is clearly detected in all single images of 180 s 
exposure. Preliminary photometry is following

Date,       UT start,    OT,    OT_err

2015-04-13  17 40 32.11  16.56  0.12
2015-04-13  17 43 36.17  16.97  0.30
2015-04-13  17 46 40.21  16.48  0.07
2015-04-13  17 49 44.26  16.73  0.11
2015-04-13  17 52 48.30  16.48  0.15
2015-04-13  17 55 52.37  16.62  0.13
2015-04-13  17 58 56.41  16.74  0.09
2015-04-13  18 02 00.58  16.63  0.13
2015-04-13  18 05 04.68  16.78  0.10
2015-04-13  18 08 08.76  16.77  0.09
2015-04-13  18 11 12.83  16.63  0.07
2015-04-13  18 14 16.87  16.74  0.06
2015-04-13  18 17 20.95  16.74  0.04
2015-04-13  18 20 25.30  16.76  0.06
2015-04-13  18 23 29.10  16.77  0.10
2015-04-13  18 26 33.15  16.90  0.08
2015-04-13  18 29 37.20  16.74  0.07
2015-04-13  18 32 41.25  16.71  0.05
2015-04-13  18 35 45.30  16.78  0.04
2015-04-13  18 38 49.36  16.77  0.03
2015-04-13  18 44 31.44  16.88  0.03
2015-04-13  18 47 35.48  16.81  0.03
2015-04-13  18 50 39.57  16.87  0.03
2015-04-13  18 53 43.66  16.92  0.03
2015-04-13  18 56 47.73  16.98  0.03
2015-04-13  18 59 51.90  17.02  0.03
2015-04-13  19 02 55.98  16.95  0.04
2015-04-13  19 06 00.64  16.94  0.04
2015-04-13  19 09 04.22  17.08  0.07
2015-04-13  19 12 08.35  17.05  0.06

The photometry is based on nearby USNO-B1.0  1618-0098185 (Xu et al., 
GCN 17693) assuming R=15.59.


GRB_name: GRB150428A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17785
SUBJECT: GRB 150428A: Swift/UVOT Upper Limits
DATE:    15/04/29 00:43:45 GMT
FROM:    Margaret Chester at PSU  <chester@swift.psu.edu>

M. M. Chester (PSU) and K. L. Page (U Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150428A
179 s after the BAT trigger (Page et al., GCN Circ. 17765).  No optical 
afterglow consistent with the enhanced XRT position (Osborne et al. GCN
Circ. 17768) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and one subsequent exposure are:

Filter         T_start(s)   T_stop(s)      Exp(s)     UL (3-sigma)

white_FC           179         329          147        >20.9
u                 3572        3726          152        >19.9

The magnitudes in the table 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: GRB150428C
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17786
SUBJECT: GRB 150428C: Swift-XRT observations
DATE:    15/04/29 13:06:40 GMT
FROM:    Kim Page at U.of Leicester  <klp5@leicester.ac.uk>

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

Swift-XRT has performed follow-up observations of the MAXI-detected
burst GRB 150428C (Honda et al. GCN Circ. 17772) in a series of
observations tiled on the sky. The total exposure time is 2.1 ks,
distributed over 7 tiles; the maximum exposure at a single sky location
was 819 s. The data were collected between T0+16.2 ks and T0+28.9 ks,
and are entirely in Photon Counting (PC) mode.

No real uncatalogued sources have been detected. Although a
low-significance source was reported by the automatic software, we believe
this is an artifact caused by high background emission. In addition, a
previously-catalogued X-ray source has been detected, however because it
is a catalogued object it is unlikely to be the afterglow.

The 3-sigma upper limit in the field ranges from ~0.01 to ~0.05 ct s^-1,
corresponding to a 0.3-10 keV observed flux of 4e-13 to 2e-12 erg cm^-2
s^-1 (assuming a typical GRB spectrum).

The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
http://www.swift.ac.uk/xrt_products/TILED_GRB00043/


GRB_name: GRB150428B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17787
SUBJECT: GRB 150428B: Swift/UVOT Upper Limits
DATE:    15/04/29 13:20:58 GMT
FROM:    Margaret Chester at PSU  <chester@swift.psu.edu>

M. M. Chester (PSU) and K. L. Page (U Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150428B 117
s after the BAT trigger (Page et al., GCN Circ. 17766). No optical
afterglow consistent with the enhanced XRT position (Beardmore et al., GCN
Circ. 17773) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposures and subsequent exposures are:

Filter      T_start(s)   T_stop(s)   Exp(s)    UL (3-sigma)

white_FC       117          267        146       >20.9
u_FC           329          579        246       >20.1
white          117         5414        588       >21.6
v              659         5825        313       >19.6
b              584         6598        445       >20.8
u              329         6440        717       >20.8
w1             708         6235        293       >20.0
m2             683         6030        294       >19.9
w2             634         5620        313       >20.2

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.40 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB150428B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17788
SUBJECT: GRB 150428B: IRSF NIR upper limits
DATE:    15/04/29 23:40:11 GMT
FROM:    Daisuke Kuroda at OAO/NAOJ  <dikuroda@oao.nao.ac.jp>

K. L. Murata (Nagoya U.), S. Nishiyama, A. Iwamatsu, I. Kawamata (Miyagi
University of Education), and T. Nagayama (Kagoshima U.)

We observed the field of GRB 150428B ( Page et al., GCN Circular #17766) with
the near-infrared (J, H, Ks) simultaneous imaging camera SIRIUS attached to 1.4
m telescope IRSF ( InfraRed Survey Facility) in Sutherland observatory, South
Africa.

The observations started on 2015-04-28 03:59:59 UT (~ 48 min. after the burst).
We could not detect the afterglow within the XRT error circle reported in the
GCN circular in the three bands.
We have obtained the following preliminary upper limits (Vega magnitude system):
 J  > 17.4
 H  > 16.8
 Ks > 15.3.

Given magnitudes were calibrated against 2MASS point sources in this field.
The upper limits were determined as the magnitudes of the faintest star within 1
arcmin from the XRT position.

This observation was carried out by IRSF and OISTER collaboration.


GRB_name: GRB150430A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17789
SUBJECT: GRB 150430A: Swift detection of a burst
DATE:    15/04/30 00:57:56 GMT
FROM:    Jamie A. Kennea at PSU/Swift-XRT  <kennea@swift.psu.edu>

V. D'Elia (ASDC), J. A. Kennea (PSU), T. Sakamoto (AGU) and
M. H. Siegel (PSU) report on behalf of the Swift Team:

At 00:21:28 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 150430A (trigger=639433).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 326.491, -27.928 which is 
  RA(J2000) = 21h 45m 57.8s
  Dec(J2000) = -27d 55' 40.8''
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty). 

The XRT began observing the field at 00:23:18.0 UT, 80 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 326.47958, -27.90212 which is equivalent to:
  RA(J2000)  = 21h 45m 55.1s
  Dec(J2000) = -27d 54' 07.6''
with an uncertainty of 5 arcseconds (radius, 90% containment). This
location is 100 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy. 

UVOT data is unavailable at this time. 

Note, due to a telemetry drop-out no GCN Notices were sent for this
burst, and limited information is available at this time. We will send
further GCN Circulars as we know more. 

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: GRB150430A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17790
SUBJECT: GRB 150430A: Swift/UVOT Upper Limits
DATE:    15/04/30 09:49:53 GMT
FROM:    Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>

S. R. Oates (IAA-CSIC/UCL-MSSL) and V. D'Elia (ASDC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150430A
115 s after the BAT trigger (D'Elia et al., GCN Circ. 17789).
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
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

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

white_FC           115          265          147         >20.6
u_FC               273          523          246         >19.7
white              115         5422          344         >21.2
v                 4196         5832          393         >19.8
b                 5017         6487          231         >20.3
u                  273         6447          639         >20.3
w1                4607         6242          393         >20.4
m2                4401         6037          393         >20.7
w2                3990         5627          393         >20.9

The magnitudes in the table are 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: GRB150430A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17791
SUBJECT: GRB 150430A: MAXI/GSC detection
DATE:    15/04/30 10:09:31 GMT
FROM:    H. Negoro at Nihon U.  <negoro@phys.cst.nihon-u.ac.jp>

M. Fujita, H. Negoro (Nihon U.), M. Serino (RIKEN), S. Nakahira, 
S. Ueno, H. Tomida,  M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA)
T. Mihara, M. Sugizaki, M. Shidatsu, J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN),
N. Kawai, T. Yoshii, Y. Tachibana, Y. Ono (Tokyo Tech),
A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU),
H. Tsunemi, R. Imatani (Osaka U.),
M. Nakajima, F. Honda, T. Namba, T. Masumitsu, K. Tanaka (Nihon U.),
Y. Ueda, T. Kawamuro, T. Hori (Kyoto U.),
Y. Tsuboi, S. Kanetou (Chuo U.),
M. Yamauchi, D. Itoh (Miyazaki U.),
K. Yamaoka (Nagoya U.),
M. Morii (ISM)
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 00:21:12 UT.

Without assumptions on the source constancy, we obtain a rectangular error
box for the transient source with the following corners:
(326.501 deg, -28.137 deg) = (21 46 00, -28 08 12) (J2000)
(326.260 deg, -28.014 deg) = (21 45 02, -28 00 49) (J2000)
(326.513 deg, -27.682 deg) = (21 46 03, -27 40 55) (J2000)
(326.753 deg, -27.805 deg) = (21 47 00, -27 48 19) (J2000)

The position of GRB 150430A (D'Elia et al. GCN #17789) is inside
of the error box. The trigger time is 16 sec before the BAT trigger.
The data download was, however, delayed for about 8.8 hours 
probably because of the data tracking problem.

The X-ray flux averaged over the scan was 512 +- 45 mCrab
(4-10keV, 1 sigma error). A simple power-law fit to the GSC 2-20 keV
spectrum gives a power-law index of 1.08  +/- 0.20.

There was no significant excess flux in the previous transit at 4/29 22:48 UT,
and in the next transit at 4/30 03:26 UT with an upper limit of 20 mCrab for each.


GRB_name: GRB150430A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17792
SUBJECT: GRB 150430A: Swift-XRT refined Analysis
DATE:    15/04/30 12:58:03 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

D.N. Burrows (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU),
J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U.
Leicester), A. D'a (INAF-IASFPA), A. Maselli  (INAF-IASFPA), A.
Melandri (INAF-OAB) and V. D'Elia report on behalf of the Swift-XRT
team:

We have analysed 10 ks of XRT data for GRB 150430A (D'Elia et al. GCN
Circ. 17789), from 84 s to 23.7 ks after the  BAT trigger. The data
comprise 207 s in Windowed Timing (WT) mode (the first 8 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. Using 8645 s of PC mode data and 15 UVOT images, we find an
enhanced XRT position (using the XRT-UVOT alignment and matching UVOT
field sources to the USNO-B1 catalogue): RA, Dec = 326.47988, -27.90181
which is equivalent to:

RA (J2000): 21h 45m 55.17s
Dec(J2000): -27d 54' 06.5"

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

The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=3.97 (+/-0.17). At T+233 s  the decay
flattens to an alpha of 0.73 (+0.07, -0.22) before breaking again at
T+4365 s to a final decay with index alpha=1.89 (+/-0.15).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.27 (+0.10, -0.09). The
best-fitting absorption column is  4.3 (+0.5, -0.4) x 10^21 cm^-2, in
excess of the Galactic value of 2.5 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 2.10 (+/-0.14) and a
best-fitting absorption column of 3.8 (+/-0.6) x 10^21 cm^-2. The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 3.6 x 10^-11 (6.0 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      3.8 (+/-0.6) x 10^21 cm^-2
Galactic foreground: 2.5 x 10^20 cm^-2
Excess significance: 9.7 sigma
Photon index:      2.10 (+/-0.14)

If the light curve continues to decay with a power-law decay index of
1.89, the count rate at T+24 hours will be 1.4 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.2 x
10^-14 (8.4 x 10^-14) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00639433.

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


GRB_name: GRB150430A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17793
SUBJECT: GRB 150430A: Fermi GBM Detection
DATE:    15/04/30 14:28:30 GMT
FROM:    Oliver Roberts at UCD/Fermi  <oliver.roberts@ucd.ie>

O.J. Roberts (UCD) and G. Younes (USRA at GWU) report
on behalf of the Fermi GBM Team:

"At 00:21:05.65  UT on the 30th of April 2015, the Fermi
Gamma-Ray Burst Monitor triggered and located GRB 150430A
(trigger 452046068 / 150430015), which was also detected
by Swift (D'Elia  et al. 2015, GCN 17789) and MAXI/GSC
(Negoro et al. 2015, GCN 17791). The GBM on-ground location
is consistent with the Swift position. The angle from the
Fermi LAT boresight is about 110 degrees.

The GBM light curve shows several bright pulses over a
duration (T90) of 116.7 s (50-300 keV). The time-averaged
spectrum from T0-4.1 s to T0+111.6 s is well fit by power
law function with an exponential high-energy cutoff. The
power law index is -0.95 +/- 0.15 and the cutoff energy,
parameterized as Epeak, is 346 +/- 57 keV.

The event fluence (10-1000 keV) in this time interval is
(2.1 +/- 0.1)E-05 erg/cm^2. The 1.024-sec peak photon
flux measured starting from T0+10.3 s in the 10-1000 keV
band is 9.7 +/- 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: GRB150430A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17794
SUBJECT: Konus-Wind observation of GRB 150430A
DATE:    15/04/30 14:38:55 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

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

The long-duration GRB 150430A
(Swift/BAT detection: D'Elia et al., GCN Circ. 17789;
MAXI/GSC detection: Fujita et al., GCN Circ. 17791;
Fermi/GBM detection: Roberts and Younes, GCN Circ. 17793)
triggered Konus-Wind at T0=1271.466 s UT (00:21:11.466).

The burst light curve shows three well separated emission episodes:
a weak episode at T-T0 ~ -320 s, the main episode at T-T0 ~ 0 s,
and a weak episode at T-T0 ~ 100 s.
The total burst duration is about 420 s.
There is a hint of soft precursor at T-T0 ~ -440 s.
The emission is seen up to ~5 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB150430_T01271/

As observed by Konus-Wind, the burst
had a fluence of 2.95(-0.75,+1.14)x10^-5 erg/cm2,
and a 256-ms peak flux, measured from T0+1.248 s,
of 4.11(-1.02,+1.09)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the main episode
(measured from T0 to T0+114.944 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.79(-0.69,+1.48),
the high energy photon index beta = -2.21(-0.66,+0.33),
the peak energy 157(-70,+93) keV
(chi2 = 69/72 dof)

The spectrum near the maximum count rate
(measured from T0+0.000 to T0+8.448 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.47(-0.35,+0.45),
the high energy photon index beta = -2.11(-0.24,+0.16),
the peak energy 194(-38,+54) keV
(chi2 = 80/97 dof)

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


GRB_name: GRB150430A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17795
SUBJECT: GRB 150430A: Swift-BAT refined analysis
DATE:    15/04/30 15:04:52 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), V. D'Elia (ASDC), N. Gehrels (GSFC),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
 
Using the data set from T-240 to T+962 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 150430A (trigger #639433)
(D'Elia, et al., GCN Circ. 17789).  The BAT ground-calculated position is
RA, Dec = 326.481, -27.919 deg, which is 
   RA(J2000)  =  21h 45m 55.5s 
   Dec(J2000) = -27d 55' 07.9" 
with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 5%.
 
The mask-weighted light curve shows several peaks starting at ~T-10 sec,
the hightest peak at ~T+2 sec, the last peak at ~T+97 sec, and ending at ~T+110 sec.
T90 (15-350 keV) is 107.1 +- 6.7 sec (estimated error including systematics).
 
The time-averaged spectrum from T-11.64 to T+108.70 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.43 +- 0.12.  The fluence in the 15-150 keV band is 6.9 +- 0.5 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+0.97 sec in the 15-150 keV band
is 5.0 +- 1.0 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/639433/BA/


GRB_name: GRB150430A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17796
SUBJECT: GRB 150430A: GROND Upper Limits
DATE:    15/04/30 22:47:25 GMT
FROM:    Alexander Kann at TLS Tautenburg  <kann@tls-tautenburg.de>

T. Schweyer (MPE Garching), D. A. Kann (TLS Tautenburg), and J. Greiner
(MPE Garching) report on behalf of the GROND team:

We observed the field of GRB 150430A (Swift trigger 639433; D'Elia et al.,
GCN # 17789) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla
Observatory (Chile).

Observations started at 07:09 UT on 2015-04-30, 6.8 hrs after the GRB
trigger. They were performed at an average seeing of 0.9" and at an
average airmass of 1.6.

Inside the 1.4" enhanced XRT error circle (Burrows et al., GCN # 17792)
and in the nearby surroundings we detect no sources.

Based on 27 min of total exposure time in g'r'i'z' and 20 min in JHK
centered 7.56 hrs after the  GRB, we estimate the following preliminary
upper limits (AB magnitudes):

g' > 24.3 mag,
r' > 24.3 mag,
i' > 23.8 mag,
z' > 23.5 mag,
J > 21.5 mag,
H > 20.8 mag, and
K > 19.5 mag.

Given magnitudes are calibrated against GROND zero points (g'r'i'z') as
well as 2MASS field stars (JHK) and are not corrected for the expected
Galactic foreground extinction corresponding to a reddening of
E_(B-V)=0.03 mag in the direction of the burst (Schlegel et al. 1998)


GRB_name: GRB150413A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17797
SUBJECT: GRB 150413A: AMI 15 GHz confirmation of radio counterpart
DATE:    15/05/01 13:08:28 GMT
FROM:    Gemma Anderson at U of Oxford  <Gemma.Anderson@physics.ox.ac.uk>

G. E. Anderson, R. P. Fender, T. D. Staley, K. Mooley (University of Oxford),
A. J. van der Horst (George Washington University), A. Rowlinson (CASS)

We re-observed the position of GRB 150413A (Markwardt et al., GCN 17688,
Ivanov et al., GCN 17689) at 15 GHz with the Arcminute Microkelvin Imager
(AMI-LA) following the  possible detection of its radio counterpart reported
in Anderson et al., GCN 17708. This observation took place on 2015 April
15.798 to 15.964 UT, corresponding to 2.2 days post-burst, resulting in a flux
 of 0.20 +/- 0.04 mJy. A follow-up AMI observation on 2015 April 23.947 to
24.114 UT, corresponding to 10.4 days post-burst, did not detection the radio
counterpart with a 3 sigma upper limit of 0.1 mJy. We therefore confirm that
the coincident radio source reported in Anderson et al., GCN 17708 is the
radio counterpart to GRB 150413A.

We thank the AMI staff for scheduling these observations.


GRB_name: GRB150423A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17798
SUBJECT: GRB 150423A: JCMT SCUBA-2 sub-mm observation
DATE:    15/05/01 22:08:22 GMT
FROM:    Ian Smith at Rice U  <ian@spacsun.rice.edu>

I.A. Smith (Rice U.), N.R. Tanvir (U. of Leicester) report:

We observed the location of the short GRB 150423A (Pagani et al.,
GCN Circ. 17728) using the SCUBA-2 sub-millimeter continuum camera
on the James Clerk Maxwell Telescope.  The observation started at
07:21 UT on 2015-04-23, corresponding to 53 minutes after the burst
trigger.  Exposures totaling 2.0 hours were made in good weather
conditions.  No source was detected, with the RMS background noise
being 1.5 mJy/beam at 850 microns and 17.4 mJy/beam at 450 microns.

We thank Callie Matulonis, Angus Mok, and Iain Coulson for the
prompt support of these observations that were taken under project
M15AI86.


GRB_name: GRB150423A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17801
SUBJECT: GRB 150423A: Chandra X-ray Observation
DATE:    15/05/03 16:46:10 GMT
FROM:    Edo Berger at Harvard  <eberger@cfa.harvard.edu>

E. Berger, R. Margutti (Harvard), and W. Fong (Univ. of Arizona) report:

"We observed the location of the short GRB 150423A (GCN #17728) with the
Chandra X-ray Observatory ACIS-S instrument starting on 2015 May 2.308 UT
for a total of 23.3 ksec.  At the location of the optical afterglow (GCNs
#17732, 17733) we detect no significant X-ray emission, and place an upper
limit on the count rate of 1.3e-4 cps (1" radius aperture).  Using the
spectral properties determined from the Swift/XRT data (GCN #17737) we
place an upper limit on the flux of the X-ray afterglow at 9.17 days
post-burst of 1.7e-15 erg/s/cm^2 (0.3-10 kev).

We thank Belinda Wilkes, Harvey Tananbaum, and the Chandra X-ray
Observatory staff for approving and carrying out this Director's
Discretionary Time observation."


GRB_name: GRB150428A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17802
SUBJECT: Konus-Wind observation of GRB 150428A
DATE:    15/05/04 14:55:51 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

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

The long-duration GRB 150428A (Swift-BAT trigger #639275:
Page, et al., GCN Circ. 17765; Baumgartner, et al., GCN Circ. 17774)
was detected by Konus-Wind in the waiting mode.

The burst light curve shows a single pulse which started approximately 
at BAT trigger time T0(BAT) and has a duration of ~45 s.

As observed by Konus-Wind, the burst had a fluence of
1.61(-0.09,+0.10)x10^-5 erg/cm2 and a 2.944-s peak flux,
measured from ~T0(BAT)+21 s, of 5.5(-0.7,+0.9)x10^-7 erg/cm2
(both in the 20 - 1200 keV energy range).

Modelling the K-W 3-channel time-integrated spectrum (from T0(BAT)-3 s
to T0(BAT)+41 s) by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha = -1.04(-0.12,+0.14), and Ep = 275(-29,+37) keV.

All the quoted errors are estimated at the 1 sigma confidence level.
All the presented results are preliminary.

The K-W light curve of this burst is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB150428A/


GRB_name: GRB150423A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17803
SUBJECT: GRB 150423A: GMG observation limit
DATE:    15/05/05 02:09:50 GMT
FROM:    Jirong Mao at Yunnan Obs  <jirongmao_obs@ynao.ac.cn>

J. Mao, Y. Fan and J.-M. Bai (YNAO) report:


We observed the field of GRB 150423A (Pagani et al., GCN 17728) with the 2.4-meter optical telescope at Gao-Mei-Gu (GMG) station of Yunnan Observatory. Observations began from 17:11:14 UT, May 2nd, 2015, about 9 days after the trigger. We did not
detect any source / rebrightening feature at the afterglow position down to a limit of z~21.0 mag with poor observational condition.


GRB_name: GRB150424A
Detection_method: VLA Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17804
SUBJECT: GRB 150424A: 9.8 GHz VLA detection
DATE:    15/05/07 17:03:52 GMT
FROM:    Wen-fai Fong at U of Arizona  <wfong@email.arizona.edu>

W. Fong (Univ. of Arizona) reports:

"We observed the position of the short-duration GRB 150424A (Beardmore et
al., GCN 17743) with the Karl G. Jansky Very Large Array (VLA) beginning on
2015 Apr 25.073 UT (18.02 hr post-burst) at a mean frequency of 9.8 GHz. In
1 hour of observations, we detect a faint radio source at the position:

RA(J2000) = 10:09:13.37
Dec(J2000) = -26:37:51.49

with an uncertainty of 0.5" in each coordinate. This position is coincident
with the position of the X-ray afterglow (Goad et al., GCN 17749) as well
as the position of the optical afterglow (Perley and McConnell., GCN 17745;
Malesani et al., GCN 17756; Kann et al., GCN 17757; Butler et al., GCN
17762).

We measure a 9.8 GHz flux density of ~31 microJy. To assess the nature of
this radio source, we obtained two additional sets of VLA observations
starting at 4.67 and 7.88 days after the burst. The source is no longer
detected in each of these observations, as well as a deep, combined image,
to 3-sigma limits of 29 microJy and 20 microJy, respectively.

Due to the fading of the radio source, as well as the positional
coincidence with the X-ray and optical afterglows, we consider this source
to be the radio afterglow of GRB 150424A.

We thank the VLA staff for quickly executing these observations."


GRB_name: GRB150510A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17805
SUBJECT: GRB 150510A: Fermi-LAT detection
DATE:    15/05/10 09:22:55 GMT
FROM:    Giacomo Vianello at SLAC  <giacomov@slac.stanford.edu>

G. Vianello (Stanford), J. Racusin (GSFC)

report on behalf of the Fermi-LAT team:

At  03:19:53.74 on May 10, 2015, Fermi-LAT detected high-energy emission
from GRB 150510A, which was also detected by Fermi-GBM (trigger 452920796/
150510139).

The best LAT on-ground location is found to be

RA, Dec = 15.138,  4.985 (J2000)

with an error radius of 1.3 deg (90% containment, statistical error
only). This was 55 deg from the LAT boresight at the time of the trigger.

Our localization has an unusually large error because so far we have
received only 60 s worth of data after the trigger. Further contacts with
the spacecraft are scheduled for the next hours. We will release another
circular if the new data will allow us to refine the localization.

Our current localization is based on 5 photons between 100 and 300 MeV,
detected within 60 seconds from the trigger time.

Due to the large localization error, a Swift ToO has not been requested.

The Fermi-LAT point of contact for this burst is Judith Racusin (
judith.racusin@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.


GRB_name: GRB150510A
Detection_method: Fermi LAT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17806
SUBJECT: GRB 150510A: Fermi-LAT Refined Analysis
DATE:    15/05/10 13:13:28 GMT
FROM:    Judith Racusin at GSFC  <judith.racusin@nasa.gov>

J. L. Racusin (NASA/GSFC), M. Axelsson (KTH), M. Yassine (LUPM), D. Kocevski (NASA/GSFC) 
report on behalf of the Fermi-LAT team:

Additional data on GRB 150510A has been downlinked from Fermi and processed, and we report 
an improved LAT localization of 

R.A., Dec = 16.16,  4.79 (J2000)

with an error radius of 0.36 deg (90% containment, statistical error only).  This was 55 deg from the 
LAT boresight at the time of the trigger.  The GRB position was within the LAT FoV from ~500 s prior 
to the trigger to ~T0+600 s, when an autonomous repoint request to the initial GBM flight position 
caused the spacecraft to slew away.

There are 13 photons with energies >100 MeV within a 12 degree radius around the GRB position. 
The highest energy photon is detected at T0+170 s with an energy of 1.5 GeV.  The burst is also 
detected in the LAT Low Energy (LLE) data with energies >30 MeV with a significance of 9 sigma 
above background with a duration of ~20 s, coinciding with the time of the GBM emission.

The GRB localization is within the Swift Sun avoidance constraint, and will not emerge until May 25, 
therefore a Swift TOO is not being requested.

The Fermi-LAT point of contact for this burst is Judith Racusin (judith.racusin@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.


GRB_name: GRB150510A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17807
SUBJECT: GRB 150510A: Fermi GBM detection
DATE:    15/05/10 17:22:58 GMT
FROM:    Eric Burns at U of Alabama  <eb0016@uah.edu>

E. Burns (UAH) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 03:19:53.74 UT on 10 May 2015, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 150510A (trigger 452920796 / 150510139),
which was also detected by the Fermi LAT (Vianello et al. 2015,
GCN 17805). The GBM on-ground location is marginally consistent
with the LAT position.

The angle of the burst direction to the Fermi LAT boresight was
55 degrees. The trigger resulted in an Autonomous Repoint Request
(ARR) that was accepted and the spacecraft slewed to the GBM
in-flight location.

The GBM light curve shows a FRED profile
with a duration (T90) of about 52 s (50-300 keV).
The time-averaged spectrum from T0+0.256 s to T0+52.480 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.04 +/- 0.01 and
the cutoff energy, parameterized as Epeak, is 1651 +/- 58 keV.

The event fluence (10-1000 keV) in this time interval is
(9.32 +/- 0.05)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.064 s in the 10-1000 keV band
is 32.0 +/- 0.3 ph/s/cm^2.

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


GRB_name: GRB150510A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17808
SUBJECT: Konus-Wind observation of GRB 150510A
DATE:    15/05/11 17:23:27 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

The long-duration, hard-spectrum, intense GRB 150510A
(Fermi-LAT detection: Vianello & Racusin, GCN 17805;
Racusin et al., GCN 17806;
Fermi-GBM detection: Burns & Meegan GCN 17807)
triggered Konus-Wind at T0=11988.505 s UT (03:19:48.505).

The KW light curve shows a FRED-like structure with
a duration of ~62 s.
The emission is visible up to ~15 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB150510_T11988/

As observed by Konus-Wind, the burst had a fluence
of 1.9(-0.1,+0.1)x10^-4 erg/cm2, and a 64-ms peak flux,
measured from T0+0.064 s, of 4.0(-0.3,+0.3)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum (measured from T0 to T0+39.168 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.99 (-0.04,+0.05),
the high energy photon index beta = -2.81 (-1.10,+0.37),
the peak energy Ep = 1253 (-129,+134) keV,
chi2 = 106/95 dof.

The spectrum near the peak count rate
(measured from T0 to T0+6.400 s)
is best fit in the 20 keV - 15 MeV range
by the cutoff power law with the following model parameters:
the photon index alpha = -0.74(-0.05,+0.05),
and the peak energy Ep = 1320(-85,+93) keV,
chi2 = 100/87 dof.
Fitting this spectrum with the Band model yields the same
values of alpha and Ep with an upper limit on the high-energy
photon index beta of -2.9

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


GRB_name: GRB150512A
Detection_method: iPTF
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17809
SUBJECT: GRB 150512A: iPTF Optical Observations
DATE:    15/05/13 18:50:52 GMT
FROM:    Leo Singer at GSFC/iPTF  <leo.p.singer@nasa.gov>

L. P. Singer (NASA/GSFC), V. Bhalerao (IUCAA), M. M. Kasliwal
(Carnegie Observatories/Princeton), and S. B. Cenko (NASA/GSFC) report on
behalf of the intermediate Palomar Transient Factory (iPTF) collaboration:

Fermi detected GRB 150512A (Fermi trigger 453118948 / bn150512432) at
2015-05-12 10:22:25.87. At 2015-05-13 03:58:15, 17.6 hours after the
burst, we began searching for optical counterparts using the Palomar
48-inch Oschin telescope (P48).

We imaged 20 fields covering an area of 144 deg^2 covering the 1-sigma
statistical+systematic region of the final Fermi GBM localization. We
estimate a 76% prior probability that these fields contain the true
location of the source. Sifting through candidate variable sources using
image subtraction and standard iPTF vetting procedures, we detected the
following optical transient candidates:

iPTF15asm, at the coordinates:
  RA(J2000)  =  13h 40m 45.03s (205.187617 deg)
  Dec(J2000) = +63d 19' 53.3"  (+63.331461 deg)
This position is 6" from the galaxy SDSS J134044.09+631954.4 (z = 0.104).
We report the following P48 photometry:
  -95 days:     R > 20.27
  +18.01 hours: R = 19.49 +/- 0.06
  +18.93 hours: R = 19.42 +/- 0.06

iPTF15asn, at the coordinates:
  RA(J2000)  =  13h 57m 40.01s (209.416716 deg)
  Dec(J2000) = +65d 08' 01.6"  (+65.133789 deg)
We report the following P48 photometry:
  -95 days:     R > 20.42
  +18.01 hours: R = 19.82 +/- 0.07
  +18.93 hours: R = 19.98 +/- 0.07

No source was visible in archival P48 and SDSS images at either position.
Times are relative to the GBM trigger. Magnitudes are in the Mould R
filter and in the AB system, calibrated with respect to point sources in
SDSS as described in Ofek et al. (2012, http://dx.doi.org/10.1086/664065).

We encourage further observations of both candidates to determine if
either is fading and potentially related to the GRB.

The diagram http://www.its.caltech.edu/~lsinger/iptf/Fermi453118948.pdf
shows the locations of our candidates and the P48 fields in relation to
the Fermi GBM 1- and 2-sigma statistical+systematic contours.


GRB_name: GRB150513A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17810
SUBJECT: GRB 150513A: Swift detection of a burst
DATE:    15/05/13 20:41:22 GMT
FROM:    Daniel Kocevski at SLAC  <dankocevski@gmail.com>

D. Kocevski (NASA/GSFC/ORAU), J. A. Kennea (PSU),
A. Y. Lien (GSFC/UMBC), K. L. Page (U Leicester) and
J. L. Racusin (NASA/GSFC) report on behalf of the Swift Team:

At 20:31:19 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 150513A (trigger=640584).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 49.058, -22.913 which is 
   RA(J2000) = 03h 16m 14s
   Dec(J2000) = -22d 54' 45"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a multi-peaked
structure with a duration of about 140 sec.  The peak count rate
was ~2000 counts/sec (15-350 keV), at ~4 sec after the trigger. 

Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 11:32 UT on 2015 May 28. There will thus be no XRT or
UVOT data for this trigger before this time. 

Burst Advocate for this burst is D. Kocevski (dankocevski 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: GRB150512A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17811
SUBJECT: GRB 150512A: Fermi GBM detection
DATE:    15/05/13 21:53:22 GMT
FROM:    Binbin Zhang at UAH  <binbin.zhang@uah.edu>

Bin-Bin Zhang (UAH) and A. von Kienlin (MPE) report on behalf of the
Fermi GBM Team:

"At 10:22:25.87 UT on 12 May 2015, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 150512A (trigger 453118948 / 150512432),
which was also detected by the iPTF (Singer et al. 2015,GCN 17809).
The GBM on-ground location is consistent with the positions of the
potential transient sources reported by iPTF (Singer et al. 2015,
GCN 17809). The angle of the burst direction to the Fermi LAT boresight
was 95 degrees.

The GBM light curve consists of several peaks with a total duration
(T90) of about 123 s (50-300 keV). The time-averaged spectrum from
T0-20 s to T0+104 s is best fit by a BAND function with Epeak = 121.5
+/- 18.7 keV, alpha = -0.9 +/- 0.1 and Beta = -2.0 +/- 0.1. The event
fluence (10-1000 keV) in this time interval is (2.17 +/- 0.06)E-05 erg/cm^2.
The 1.0-sec peak photon flux measured starting from T0+101 s in the 10-1000
keV band is 5.5 +/- 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: GRB150513A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17812
SUBJECT: GRB 150513A: Fermi-LAT detection
DATE:    15/05/14 04:43:47 GMT
FROM:    Daniel Kocevski at GSFC  <daniel.kocevski@nasa.gov>

GRB 150513A: Fermi-LAT detection

D. Kocevski (NASA/GSFC), G. Vianello (Stanford), and M. Arimoto (Tokyo Tech),
report on behalf of the Fermi-LAT team:

At 20:33:15.25 on May 05, 2015, Fermi-LAT detected high-energy emission from GRB 150513A, which was also detected by Fermi-GBM (trigger 453241998) and Swift-BAT (Kocevski et al. 2015, GCN 17810).

The best LAT on-ground location is found to be

RA, Dec 49.2, -23.2 (J2000)

with an error radius of 0.4 deg (90% containment, statistical error only). This position was 50 deg from the LAT boresight at the time of the trigger and consistent with the position found by Swift-BAT.

The data from the Fermi-LAT show a significant increase in the event rate that is spatially and temporally correlated with the GBM emission with high significance. The highest-energy event is a 2.1 GeV event detected at T0 + 60 s. The GRB was observable from T0 to T0 + 385 s, before the spacecraft entered the South Atlantic Anomaly, where data gathering is disabled.

The Fermi-LAT point of contact for this burst is Makoto Arimoto (arimoto@hp.phys.titech.ac.jp<mailto:arimoto@hp.phys.titech.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.


GRB_name: GRB150513A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17813
SUBJECT: GRB 150513A: Fermi GBM detection
DATE:    15/05/14 08:21:13 GMT
FROM:    George A. Younes at USRA/NASA/MSFC  <younes.ge@gmail.com>

Younes G. (USRA at GWU) and Meegan C. (UAH) report on behalf of the Fermi GBM Team:

"At 20:33:15.25  UT, on 2015 May 13, the Fermi
Gamma-Ray Burst Monitor triggered and located GRB 150513A
(trigger 453241998 / 150513856) which was also detected
by Swift (Kocevski  et al. 2015, GCN 17810) and Fermi/LAT
(Kocevski et al. 2015, GCN 17812). The GBM on-ground location
is consistent with the Swift position. The angle from the
Fermi LAT boresight is about 45 degrees.

The GBM light curve shows two peaks separated by about 150 s
with a duration (T90) of 165 s (50-300 keV). The time-averaged
spectrum from T0-161.5 s to T0+4.3 s is well fit by a BAND function
with Epeak = 252 +/- 63 keV, alpha = -0.9 +/- 0.1, and
beta = -1.69 +/- 0.06.

The event fluence (10-1000 keV) in this time interval is
(1.36 +/- 0.04)E-05 erg/cm^2. The 1 second peak photon
flux measured starting from T0+0.2 s in the 10-1000 keV
band is 4.1 +/- 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: GRB150513A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17814
SUBJECT: GRB 150513A: Swift-BAT refined analysis
DATE:    15/05/14 17:50:21 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <james.r.cummings@nasa.gov>

GRB 150513A: Swift-BAT refined analysis

A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(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 150513A (trigger #640584) (Kocevski, et al.,
GCN Circ. 17810).  The BAT ground-calculated position is
RA, Dec = 49.044, -22.868 deg which is
    RA(J2000)  =  03h 16m 10.6s
    Dec(J2000) = -22d 52' 03.3"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 64%.

The mask-weighted light curve shows multiple peaks with a return to background
levels in between them.  T90 (15-350 keV) is 162 +- 5 sec (estimated error
including systematics).

The time-averaged spectrum from T-54.33 to T+129.36 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.40 +- 0.07.  The fluence in the 15-150 keV band is 5.4 +- 0.2 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T+115.41 sec in the 15-150 keV band
is 2.9 +- 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.


GRB_name: GRB150512A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17815
SUBJECT: GRB 150512A: CrAO optical observations
DATE:    15/05/14 19:30:18 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

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

We observed the two OT candidates (Singer et al., GCN 17809)  of the 
Fermi GRB  150512A (Zhang et al., GCN 17811) with ZTSh telescope of CrAO 
observatory starting on May. 13 (UT) 21:04:53. Both candidats are 
clearly visible in our images. Photometry of the candidates is following

iPTF15asn:
Date       UT start   t-T0     Filter   Exp.    Source    Err.
                       (mid, days)       (s)
2015-05-13 21:04:53   1.45795  R        16*120  19.20     0.03


iPTF15asm:
Date       UT start   t-T0     Filter   Exp.    Source    Err.
                       (mid, days)       (s)
2015-05-13 21:46:49   1.48417  R        12*120  19.40     0.02

Photometry of iPTF15asm might be biased by nearby galaxy SDSS 
J134044.09+631954.4. However both sources do not fade in comparison with 
early observations (Singer et al., GCN 17809) and most probably cannot 
be considered as afterglow.

Photometry is in Vega, and based on following SDSS stars

SDSS9_id               R_Lupton
J135741.63+650759.8    16.82
J135738.44+650852.4    18.03
J135752.58+650922.2    18.14


GRB_name: GRB150514A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17816
SUBJECT: GRB 150514A: Fermi-LAT detection  
DATE:    15/05/15 04:56:37 GMT
FROM:    Daniel Kocevski at GSFC  <daniel.kocevski@nasa.gov>

D. Kocevski (NASA/GSFC) and M. Arimoto (Tokyo Tech),
report on behalf of the Fermi-LAT team:

At 18:35:05.35 on May 14, 2015, Fermi-LAT detected high-energy emission from GRB 150514A, which was also detected by Fermi-GBM (trigger 453321308).

The best LAT on-ground location is found to be

RA, Dec = 74.85, -60.91 (J2000)

with an error radius of 0.12 deg (90% containment, statistical error only). This position was 40 deg from the LAT boresight at the time of the trigger.

The data from the Fermi-LAT show a significant increase in the event rate that is spatially and temporally correlated with the GBM emission with high significance. The LAT localization relies heavily on the detection of a single 6.5 GeV event at T0 + 400s, roughly 2.2 deg from the final GBM position. The GRB was observable from T0 to T0 + 600 s, before the spacecraft entered the South Atlantic Anomaly, where data gathering is disabled.

The Fermi-LAT point of contact for this burst is Makoto Arimoto (arimoto@hp.phys.titech.ac.jp<mailto:arimoto@hp.phys.titech.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.


GRB_name: GRB150514A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17817
SUBJECT: GRB 150514A: Swift ToO observations
DATE:    15/05/15 05:52:16 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift has initiated a ToO observation of the Fermi/LAT GRB 150514A. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020510

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the Fermi/LAT event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a 
GCN Circular after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

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


GRB_name: GRB150514A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17818
SUBJECT: GRB 150514A: Swift-XRT afterglow detection
DATE:    15/05/15 09:52:17 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), K.L. Page (U.
Leicester), C. Pagani (U. Leicester), A.P. Beardmore (U. Leicester), A.
Maselli  (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB),
D.N. Burrows (PSU) and P.A. Evans (U. Leicester) report on behalf of
the Swift-XRT team:

Swift-XRT has performed follow-up observations of the
Fermi/LAT-detected burst GRB 150514A (Kocevski et al. GCN Circ. 17816),
collecting 1.3 ks of Photon Counting (PC) mode data between T0+40.8 ks
and T0+42.2 ks. 

Three uncatalogued X-ray sources are detected, of which one ("Source
1") is above the RASS limit, and is therefore likely the GRB afterglow.
 The position of this source is RA, Dec=74.8750, -60.9691 which is
equivalent to:

RA (J2000): 04:59:30.00
Dec(J2000): -60:58:08.8

with an uncertainty of 3.9 arcsec (radius, 90% confidence).  This
position is 3.6 arcmin from the Fermi/LAT position.  The light curve is
consistent with a constant source of mean count rate 5.4e-02 ct/sec. A
power-law fit gives an index of 3.17 (+0.05, -4.47).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.2 (+0.7, -0.4). The
best-fitting absorption column is  3 (+11, -1) x 10^20 cm^-2,
consistent with the Galactic value of 2.0 x 10^20 cm^-2 (Willingale et
al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux
conversion factor deduced from this spectrum  is 2.9 x 10^-11 (3.3 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      3 (+11, -1) x 10^20 cm^-2
Galactic foreground: 2.0 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:      2.2 (+0.7, -0.4)

The results of the XRT-team automatic analysis of the likely afterglow
are at http://www.swift.ac.uk/ToO_GRBs/00020510/index_1.php.
The results of the full analysis of the XRT observations are available
at http://www.swift.ac.uk/ToO_GRBs/00020510.

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


GRB_name: GRB150514A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17819
SUBJECT: GRB 150514A: Fermi GBM Detection
DATE:    15/05/15 11:32:33 GMT
FROM:    Oliver Roberts at UCD/Fermi  <oliver.roberts@ucd.ie>

O.J. Roberts (UCD), Bin-Bin Zhang (UAH) and
C.Meegan (UAH) report on behalf of the Fermi GBM Team:

"At 18:35:05.35 UT on the 14th of May 2015, the Fermi
Gamma-Ray Burst Monitor triggered and located GRB 150514A
(trigger 453321308 / 150514774), which was also detected
by Fermi-LAT (Kocevski et al. 2015, GCN 17816). An
afterglow likely to be from this event was also found by
Swift (Kennea et al. 2015, GCN 17818). The GBM on-ground
location is consistent with the LAT and Swift XRT positions.

The angle from the Fermi LAT boresight is about 38 degrees.

The GBM light curve consists of a single bright, FRED-like
pulse over a duration (T90) of 10.8 s (50-300 keV). The
time-averaged spectrum from T0+0.0 s to T0+11.3 s is well
fit by a Band function, with an Epeak = 73 +/- 6 keV,
alpha = -1.34 +/- 0.07, and beta = -2.51 +/- 0.17.

The event fluence (10-1000 keV) in this time interval is
(4.9 +/- 0.2)E-06 erg/cm^2. The 1.024-sec peak photon
flux measured starting from T0+0.5 s in the 10-1000 keV
band is 19.9 +/- 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: GRB150514A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17820
SUBJECT: GRB 150514A: Swift/UVOT Detection
DATE:    15/05/15 13:50:53 GMT
FROM:    Frank Marshall at GSFC  <femarsha@khamseen.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC) and J. K. Cannizzo (GSFC/UMBC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150514A
40750 s after the LAT trigger (Kocevski and Arimoto, GCN Circ. 17816).
A source consistent with the XRT position (Kennea et al. GCN Circ. 17818)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  04:59:30.30 =  74.87623 (deg.)
    Dec (J2000) = -60:58:06.3  = -60.96841 (deg.)
with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence).

Preliminary detections using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: 

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

white            41402        41850          440         18.60 +/- 0.04
v                42049        42222          170         18.71 +/- 0.20
u                40750        41396          636         18.20 +/- 0.05

The magnitudes in the table 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: GRB150514A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17821
SUBJECT: GRB 150514A: GROND Bright Afterglow Confirmation
DATE:    15/05/16 00:35:29 GMT
FROM:    Alexander Kann at TLS Tautenburg  <kann@tls-tautenburg.de>

R. Yates, F. Knust (both MPE Garching), D. A. Kann (TLS Tautenburg), and
J. Greiner (MPE Garching) report on behalf of the GROND team:

We observed the field of GRB 150514A (Fermi trigger 453321308; LAT
detection: Kocevski et al., GCN # 17816; GBM detection: Roberts et al.,
GCN # 17819) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla
Observatory (Chile).

Observations started at 23:36 UT on 2015-05-15, 29.0 hrs after the GRB
trigger. They were performed at an average seeing of 1".5 and at an
average airmass of 2.1.

Coincident with the UVOT source reported by Marshall & Cannizzo (GCN #
17820), we detect a bright source.

Based on 7.7 min of total exposure time in g'r'i'z' and 8 min in JHK
centered 29.15 hrs after the GRB, we estimate the following preliminary
magnitudes (all in the AB system):

g' = 20.5 +/- 0.1 mag,
r' = 20.1 +/- 0.1 mag,
i' = 19.9 +/- 0.1 mag,
z' = 19.6 +/- 0.1 mag,
J = 19.2 +/- 0.2 mag, and
H = 18.6 +/- 0.2 mag.

Compared with the UVOT detections reported by Marshall & Cannizzo (GCN #
17820; 18th magnitude), the source has clearly faded, establishing it as
the afterglow of GRB 150514A.

We note that similar to other LAT-detected GRBs, this is a very bright
afterglow. Spectral follow-up is encouraged.

Given magnitudes are calibrated against GROND zero points (g'r'i'z') as
well as 2MASS field stars (JHK) and are not corrected for the expected
Galactic foreground extinction corresponding to a reddening of E_(B-V) =
0.02 mag in the direction of the burst (Schlegel et al. 1998).


GRB_name: GRB150514A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17822
SUBJECT: GRB 150514A: VLT/X-shooter redshift
DATE:    15/05/16 01:30:16 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), D. Xu (NAOC/CAS), 
D. Malesani (DARK/NBI), N. R. Tanvir (U. Leicester) report on behalf of 
the X-shooter GRB collaboration:

We observed the optical afterglow of GRB 150514A (Kocevski et al. 
GCN 17816, Kennea et al. GCN 17818, Roberts et al. GCN 17819, 
Marshall et al. GCN 17820, Yates et al. GCN 17821) with X-shooter 
at the Very Large Telescope (Paranal Observatory, Chile). Observations 
started at 23:04 UT on 15 May 2015 (28.4 hr after the burst) and 
consisted of 4 x 600 s exposures covering the range between 3000 and 
24800 AA.

The afterglow is well detected in the acquisition image at R(Vega) = 
19.5 mag, calibrated with two nearby USNO B1 stars. The spectrum 
shows a clear continuum over the entire range and absorptions of FeII, 
MgII and MgI at a common redshift of 0.807, which we consider to be 
the redshift of the GRB.

We acknowledge the excellent support provided by Paranal staff, and in
particular John Pritchard and Dimitri Gadotti.


GRB_name: GRB150514A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17823
SUBJECT: Konus-Wind observation of GRB 150514A
DATE:    15/05/18 15:01:37 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

The long-duration GRB 150514A
(Fermi-LAT detection:  Kocevski & Arimoto , GCN 17816;
Fermi-GBM detection:  Roberts, Zhang & Meegan GCN 17819)
triggered Konus-Wind at 66905.130 s UT (18:35:05.130).

The KW light curve shows a single pulse with a duration of ~10 s.
The emission is visible up to ~5 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB150514_T66905/

As observed by Konus-Wind, the burst had a fluence
of 3.7(-0.7,+0.7)x10^-6 erg/cm2, and a 64-ms peak flux,
measured from T0+0.448 s, of 3.4(-0.6,+0.6)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum (measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 15 MeV range
by the cutoff power law with the following model parameters:
the photon index alpha = -1.44(-0.29,+0.33),
and the peak energy Ep = 60(-14,+10) keV,
chi2 = 87/89 dof.
Fitting this spectrum with the GRB (Band) function yields
the following model parameters:
the low-energy photon index alpha = -1.25 (-0.23,+0.26),
the high energy photon index beta < -2.52 (upper limit),
the peak energy Ep = 58 (-9, +9) keV,
chi2 = 85/88 dof.

Assuming the redshift z=0.807 (de Ugarte Postigo et al., GCN 17822)
and a standard cosmology model with H_0 = 70 km/s/Mpc,
Omega_M = 0.27, and Omega_Lambda = 0.73,
we estimate the following rest-frame parameters:
the isotropic energy release E_iso is ~6.3x10^51 erg,
the peak luminosity L_iso is ~1.0x10^52 erg/s,
and the rest-frame peak energy of the time-integrated spectrum,
Ep,i, is ~108 keV.

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


GRB_name: GRB150514A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17824
SUBJECT: GRB 150514A: Further Swift observations
DATE:    15/05/18 15:26:42 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P.A. Evans (U. Leicester), M. de Pasquale (MSSL/UCL) and J. K. Cannizzo
(GSFC/UMBC) report on behalf of the Swift team

Swift has performed further observations of GRB 150514A (Kocevski and
Arimoto, GCN Circ. 17816), collecting a further 2 ks of data, from
T0+120.9 ks to T0+122.9 ks. The object previously detected in the XRT
(Kennea et al. GCN Circ. 17818) and UVOT (Marshall & Cannizzo, GCN Circ.
17820) has faded in both instruments.

The UVOT counterpart was detected with a white magnitude of 20.51
+/-0.15, which gives a power-law decay index of 1.63 +/- 0.15.
The X-ray counterpart was detected with a count-rate of
(1.04 +/- 0.03) x 10^-2 ct/sec, which gives a power-law decay index of
1.4 +/- 0.5, consistent with the slope measured from the UVOT data.

This circular is an official result of the Swift team.


GRB_name: GRB150518A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17825
SUBJECT: GRB 150518A: MAXI/GSC detection
DATE:    15/05/18 23:27:34 GMT
FROM:    H. Negoro at Nihon U.  <negoro@phys.cst.nihon-u.ac.jp>

T. Kawamuro (Kyoto U.), S. Nakahira, S. Ueno, H. Tomida, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA), 
T. Mihara, M. Sugizaki, M. Serino, M. Shidatsu, J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN), 
N. Kawai, T. Yoshii, Y. Tachibana (Tokyo Tech), 
A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU), 
H. Tsunemi, R.Imatani (Osaka U.), 
H. Negoro, M. Nakajima, K. Tanaka, T. Masumitsu (Nihon U.), 
Y. Ueda, T. Hori (Kyoto U.), 
Y. Tsuboi, S. Kanetou (Chuo U.), 
M. Yamauchi, D. Itoh (Miyazaki U.), 
K. Yamaoka (Nagoya U.), M. Morii (ISM)
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray 
transient source at 21:42:14 UT.
Assuming that the source flux was constant over the transit,
we obtain the source position at

(R.A., Dec) = (234.342 deg, 16.307 deg) = (15 37 22, +16 18 25) (J2000)

with a statistical 90% C.L. elliptical error region with long and short radii 
of 0.20 deg and 0.20 deg, respectively. The roll angle of long axis from 
the north direction is 75.0 deg counterclockwise. There is an additional 
systematic uncertainty of 0.1 deg (90% containment radius).

The X-ray flux averaged over the scan was 327 +- 49 mCrab
(4-10keV, 1 sigma error).

Without assumptions on the source constancy,we obtain a rectangular error
box for the transient source with the following corners:

(R.A., Dec) = (233.970 deg, 15.521 deg) = (15 35 52, +15 31 15) (J2000)
(R.A., Dec) = (233.627 deg, 15.744 deg) = (15 34 30, +15 44 38) (J2000)
(R.A., Dec) = (234.594 deg, 16.941 deg) = (15 38 22, +16 56 26) (J2000)
(R.A., Dec) = (234.939 deg, 16.717 deg) = (15 39 45, +16 43 01) (J2000)

There was no significant excess flux in the previous transit at 5/18 21:39 UT.


GRB_name: GRB150518A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17826
SUBJECT: GRB 150518A: Tiled Swift observations
DATE:    15/05/19 00:43:18 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift has initiated a series of observations, tiled on the sky, of the
MAXI GRB 150518A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00044

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. The probability of finding
serendipitous sources, unrelated to the MAXI event is high: any X-ray source
considered to be a probable afterglow candidate will be reported via a GCN Circular
after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

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


GRB_name: GRB150518A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17827
SUBJECT: GRB 150518A: Swift-XRT afterglow detection
DATE:    15/05/19 10:18:56 GMT
FROM:    Claudio Pagani at U of Leicester  <cp232@star.le.ac.uk>

B. Sbarufatti (INAF-OAB/PSU), C. Pagani (U. Leicester), A.P. Beardmore
(U. Leicester), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V.
D'Elia (ASDC), D.N. Burrows (PSU), J.A. Kennea (PSU) and P.A. Evans (U.
Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has performed follow-up observations of the MAXI-detected
burst GRB 150518A (Kawamuro et al. GCN Circ. 17825) in a series of
observations tiled on the sky. The total exposure time is 2.4 ks,
distributed over 7 tiles; the maximum exposure at a single sky location
was 742 s. The data were collected between T0+10.4 ks and T0+20.2 ks,
and are entirely in Photon Counting (PC) mode. 

An uncatalogued X-ray source is detected and is above the RASS limit,
and is therefore likely the GRB afterglow.  The position of this source
is RA, Dec=234.2006, +16.3291 which is equivalent to:

RA (J2000): 15:36:48.14
Dec(J2000): +16:19:44.9

with an uncertainty of 3.8 arcsec (radius, 90% confidence).  This
position is 8.2 arcmin from the MAXI position. The light curve is
consistent with a constant source of mean count rate 4.0e-01 ct/sec. A
power-law fit gives an index of 0.4 (+0.7, -0.9).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 3.6 (+1.0, -0.8). The
best-fitting absorption column is  8.2 (+4.0, -3.2) x 10^21 cm^-2, in
excess of the Galactic value of 3.4 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 2.2 x 10^-11 (2.1 x 10^-10) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      8.2 (+4.0, -3.2) x 10^21 cm^-2
Galactic foreground: 3.4 x 10^20 cm^-2
Excess significance: 4.1 sigma
Photon index:      3.6 (+1.0, -0.8)

The results of the XRT-team automatic analysis of the likely afterglow
are at http://www.swift.ac.uk/xrt_products/TILED_GRB00044/index_1.php.
The results of the full analysis of the tiled XRT observations are
available at http://www.swift.ac.uk/xrt_products/TILED_GRB00044.

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


GRB_name: GRB150518A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17828
SUBJECT: Swift/UVOT observations of GRB150518A
DATE:    15/05/19 14:27:38 GMT
FROM:    Massimiliano de Pasquale at IASF-Palermo  <mdp@ifc.inaf.it>

M. De Pasquale (MSSL-UCL) and B.Cenko (NASA-GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150518A
10383 s after the MAXI-GSC trigger (Kawamuro et al, GCN Circ. 17825).

No UVOT source is detected at the XRT position or within the XRT error
circle (Sbarufatti et al., GCN Circ. 17827) in the initial UVOT exposures.

Preliminary 3-sigma upper limit using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) is

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag U.L.

u                10383       20164          364            >20.3


The magnitudes in the table 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).
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GRB_name: GRB150518A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17829
SUBJECT: GRB 150518A: Xinglong2.16m optical afterglow detection
DATE:    15/05/19 23:26:00 GMT
FROM:    Dong Xu at NAOC/CAS  <dong.dark@gmail.com>

Dong Xu (NAOC/CAS), Xue-Bing Wu, Qian Yang (PKU) report

We observed the field of the XRT transient (Sbarufatti et al., GCN
17827), which is very likely the X-ray counterpart of GRB 150518A
(Kawamuro et al., GCN 17825) , using the 2.16m telescope located at
Xinglong, Hebei, China. Observations started at 14:23:06 UT (i.e.,
16.68 hr after the burst) in a rather poor seeing of 3", and 4x300s
R-band frames were obtained.

At the XRT-UVOT enhanced position (R.A. = 15:36:48.25, Dec. =
+16:19:47.3 , Err. Rad: = 2.2â€²â€²), an optical source is well detected
at m(R) = 20.3 +/- 0.2 mag, calibrated with nearby SDSS stars. The
source largely looks round in our stacked image.

We note that there exists a source at the XRT-UVOT position that is
already detected and classified as a galaxy by SDSS (u=22.88, g=22.14,
r=21.43, i=21.24, z=20.74), with a photometric redshift of z_ph=0.35
+/- 0.11. The Xinglong detection is brighter than the SDSS detection
by about 1 magnitude in the R/r filters, and we thus think that it is
the optical afterglow of the GRB. If the afterglow is indeed
associated with the galaxy at such a redshift, it would be doable to
search for a GRB-associated supernova.

We thank Junjun Jia for carrying out these observations.


GRB_name: GRB150518A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17830
SUBJECT: GRB 150518A: GMG observation
DATE:    15/05/20 01:16:47 GMT
FROM:    Jirong Mao at Yunnan Obs  <jirongmao_obs@ynao.ac.cn>

J. Mao, X. Zhang and J. Bai (YNAO) report:


We observed the Swift-XRT field of GRB 150518A (Sbarufatti et al., GCN 17827) with the 2.4-meter optical telescope at Gao-Mei-Gu (GMG) station of Yunnan Observatory. Observations began from 16:02:40 UT, May 19, 2015, about 18.3 hours after the trigger. At the position of RA=15:36:48.27 DEC=16:19:47.1, we clearly detect one source with roughly estimated magnitude r'~21.2+/- 0.1. We could not distinguish the SDSS galaxy noticed by Xu et al. (GCN 17829) and the afterglow at this position. Detailed analysis is ongoing.


We thank D. Xu for his kind information.


GRB_name: GRB150518A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17831
SUBJECT: GRB 150518A: RATIR optical observations
DATE:    15/05/20 06:28:43 GMT
FROM:    Owen Littlejohns at Az State U  <olittlej@asu.edu>

Owen Littlejohns (ASU), Nat Butler (ASU), Alan M. Watson (UNAM),
Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer
(UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC),
Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Eleonora Troja
(GSFC), Enrico Ramirez-Ruiz (UCSC), Jos A. de Diego (UNAM), Leonid
Georgiev (UNAM), Jess Gonzlez (UNAM), Carlos Romn-Ziga (UNAM),
Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:

We observed the field of GRB 150518A (Kawamuro, et al., GCN 17825)
with the Reionization and Transients Infrared Camera (RATIR;
www.ratir.org) on the 1.5m Harold Johnson Telescope at the
Observatorio Astronmico Nacional on Sierra San Pedro Mrtir from
2015/05 20.15 to 2015/05 20.24 UTC (29.94 to 32.08 hours after the
BAT trigger), obtaining a total of 1.78 hours exposure in the r, i
and z bands.

For a source within the Swift-XRT error circle (Sbarufattim et al.,
GCN 17827), in comparison with the SDSS DR9, we obtain the
following detections and upper limit (3-sigma):

  r     21.26 +/- 0.04
  i     21.04 +/- 0.04
  z     > 20.08

These magnitudes are in the AB system and are not corrected for
Galactic extinction in the direction of the GRB. This source is
spatially consistent with the catalogued galaxy SDSS
J153648.25+161946.9, as previously reported by Xinglong Station
(Xu, et al., GCN 17829). We note that the RATIR detections in the
r and i bands are brighter than the SDSS catalogue values,
indicating that the GRB may indeed be within the galaxy, providing
an excess flux. We also note that our detections are consistent
with those from Xinglong Station.

We thank the staff of the Observatorio Astronmico Nacional in San
Pedro Mrtir.


GRB_name: GRB150518A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17832
SUBJECT: GRB 150518A: VLT/X-shooter redshift of the likely host galaxy
DATE:    15/05/20 07:44:28 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>

D. Xu (NAOC/CAS), A. J. Levan (Univ. Warwick), A. de Ugarte Postigo 
(IAA/CSIC), N. R. Tanvir (Univ. Leicester), D. Malesani (DARK/NBI), J. 
P. U. Fynbo (DARK/NBI), report on behalf of the X-shooter GRB collaboration.

We observed the optical counterpart (Xu et al., GCN 17829; Mao et al., 
GCN 17830; Littlejohns et al., GCN 17831) of the MAXI GRB 150518A 
(Kawamuro et al., GCN 17825; Sbarufatti et al., GCN 17827) using the 
X-shooter spectrograph at the ESO Very Large Telescope (VLT).

A total of 40 min integration was secured starting on 2015 May 20.184 UT 
(1.28 days after the GRB) covering the wavelength range 3000-18000 AA. 
The counterpart, which may include light from both host galaxy and 
afterglow, is clearly detected, and a number of prominent emission lines 
are visible. Among others, we identify the Balmer lines, [O II] 3727, [O 
III] 4957,5007, [N II], [S II], all at a common redshift of z = 0.256.

At this redshift, any supernova similar to other associated with GRBs 
would peak at R ~ 21. Although extinction along the line of the sight to 
the burst is unknown at present, the low redshift makes GRB 150518A an 
ideal opportunity for supernova characterisation.

We acknowledge excellent support from the observing staff in Paranal, in 
particular Dimitri Gadotti, Marcelo Lopez, and John Pritchard.


GRB_name: GRB150518A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17833
SUBJECT: GRB 150518A: Correction
DATE:    15/05/20 09:24:40 GMT
FROM:    H. Negoro at Nihon U.  <negoro@phys.cst.nihon-u.ac.jp>

H. Negoro (Nihon U.), T. Kawamuro (Kyoto U.), S. Nakahira (JAXA),
M. Serino (RIKEN) on hehalf of the MAXI team:

The previous scan transit time reported in GCN 17825 (GRB 150518A)
was incorrect. The correct time was 20:09 UT on May 18, and not 21:39.

We apologize fo the mistake.


GRB_name: GRB150518A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17834
SUBJECT: GRB 150518A: SAO RAS optical observations
DATE:    15/05/20 18:42:42 GMT
FROM:    Moskvitin Alexander at SAO RAS  <mosk@sao.ru>

A. S. Moskvitin (SAO RAS) report on behalf of larger GRB follow-up
collaboration:

The field of GRB 150518A (Kawamuro et al.,  GCNC 17825; Sbarufatti et al.,
GCNC 17827) was observed with the Zeiss-1000, 1-m telescope of SAO RAS.
The observations were carried out on the May, 19, 20:10:25 -- 21:26:30 UT
(T - T0 ~ 23 hours). 12 x 300 sec frames in Rc filter were obtained.

We clearly detect the source mentioned by the other teams (Xu et al.,
GCNC 17829, 17832; Mao et al., GCNC 17830; Littlejohns et al., GCNC 17831).
The magnitude of the object is R = 21.2 +/- 0.1 is almost equal
to the magnitude of SDSS J153648.25+161946.9 (within the errors),
probable host galaxy of GRB, so we can not find a significant excess from
the
possible OT.

Photometry is based on the nearby stars, whose SDSS magnitudes were
transformed to UBVRI system. The magnitude of object is not corrected
for the Galactic extinction.


GRB_name: GRB150518A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17835
SUBJECT: GRB 150518A : Xinglong TNT upper limit
DATE:    15/05/21 04:01:03 GMT
FROM:    L.P. Xin at NAOC  <xlp@bao.ac.cn>

L. P. Xin,   X. F. Wang,  J. Y. Wei,  Y. L. Qiu,  J. S. Deng,
J. Wang,  X. H. Han and C. Wu on behalf of EAFON report:
 
We  observed GRB 150518A (Kawamuro, et al., GCN 17825)
with Xinglong  0.8-m TNT telescope during 2015-05-20, 
16:51:46 and 18:16:34 (UT), bout 43.2-44.7 hour after the trigger time.
 
No any source was detected in our 17*300sec R-band coadded image within 
the Swift-XRT error circle (Sbarufattim et al., GCN 17827) and at the 
location of the reported source (Xu et al., GCN 17829; Mao et al., GCN 17830) 
down to the 3 sigma limit of 20.7 mag, calibrated by USNO B1.0 R2 mag.


GRB_name: GRB150518A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17836
SUBJECT: GRB 150518A: Swift-XRT follow-up observations
DATE:    15/05/21 08:07:23 GMT
FROM:    Claudio Pagani at U of Leicester  <cp232@star.le.ac.uk>

C. Pagani (U. Leicester) reports on behalf of the Swift team:

A second epoch of XRT data was collected on the field of the MAXI-detected burst: GRB 150518A (Kawamuro et al., GCN Circ. 17825) on 2015 May 20. The observations consist of 5 ks of PC mode data, from T0+146 ks to T0+154 ks.

The X-ray source reported in GCN Circ. 17827, Sbarufatti et al., measured at a mean count rate of 3.4 x 10^-1 count s^-1 (0.3-10 keV) in the first epoch of XRT observations has faded with a power law decay index of alpha=1.04 +/- 0.11 to a mean count rate of 3.1 x 10^-2 count s^-1 (0.3-10 keV) in the second epoch. We therefore confirm that this is the X-ray afterglow of GRB 150518A.

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


GRB_name: GRB150518A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17837
SUBJECT: Konus-Wind observation of  GRB 150518A
DATE:    15/05/21 11:15:33 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

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

At about 15 minutes before the MAXI/GSC trigger on GRB 150518A
(Kawamuro, et al., GCN Circ. 17825; T0(MAXI)=21:42:14 UT)
Konus-Wind detected in the waiting mode a burst of high X-ray/soft
gamma-ray emission which had a duration of ~250 s.

Taking in account the proximity of this burst to the MAXI/GSC trigger
and consistency of the KW ecliptic latitude response with the position
of GRB 150518A we suggest this burst is the main part of GRB 150518A.
There is a hint of emission in the KW softest energy band (20-80 keV)
around T0(MAXI).

Due to a gap in the data during the main episode we cannot accurately
estimate the burst energetics.

The K-W light curve of this burst is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB150518A/


GRB_name: GRB150518A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17838
SUBJECT: GRB 150518A: MASTER-net before, early and after  optical stereoscopic observations with possible MP discovery inside MAXI error box 
DATE:    15/05/21 13:09:21 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

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

D.Buckley, S. Potter, A.Kniazev, M.Kotze
South African Astronomical Observatory

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

K.Ivanov, O.Gres, N.M.Budnev, S.Yazev, O.Chuvalaev, 
V.A.Poleshchuk
Irkutsk State University

V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov, A.Gabovich
Blagoveschensk Educational State University, Blagoveschensk

V.Krushinski, I.Zalozhnih,  A. Popov
Ural Federal University, Kourovka

Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

Claudio Mallamaci, Carlos Lopez and Federico Podest
Observatorio Astronomico Felix Aguilar (OAFA)

MASTER-Kislovodsk  robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
FOV = 2x2 square degrees in paralel mode ( Lipunov et al., 2010, MASTER 
Robotic Net, Advances in Astronomy, vol. 2010, pp. 1-7)) located in 
Kislovodsk was pointed to the  MAXI/GSC GRB150518A 
(Kawamuro et al., GCN 17825) 21 sec after notice time and 3189 sec after 
trigger time at 2015-05-18 22:35:43 UT. On our first (180s exposure) 
image we do not  found OTs within Swift/XRT  erro-box  (Sbarufatti et al., 
GCN 17827)  brighter then 18.5 .

But we see bright object at positon:  15h 36m 53.67s , +16d 19m  36s.5
with 17.5  unfiltered mag  outside XRT and inside MAXI.


MASTER-SAAO  robotic telescope (MASTER-Net: http://observ.pereplet.ru,
FOV = 2x2 square degrees in paralel mode ( Lipunov et al., 2010, MASTER
Robotic Net, Advances in Astronomy, vol. 2010, pp. 1-7)) located in
Souht Africa Astronomical Observatory was pointed to the  MAXI/GSC 
GRB150518A
(Kawamuro et al., GCN 17825) 13 sec after notice time and 3189 sec after
trigger time at 2015-05-18 22:35:35 UT. On our first (180s exposure)
image we not  found OTs within Swift/XRT error-box (Sbarufatti et al., 
GCN 17827)  brighter then
17.1 .

But we see bright object at positon:  15h 36m 51.70s , +16d 19m  13s.6
with ~ 17.0  unfiltered mag  outside Swift/XRT and inside MAXI.

  There is one asteroid MPC 2010 KL61 with poorly
astrometrical efemerids (Leave for survey recovery) at MPC Data Base.
The offset both Russian and South Africa OT positiion 36 arc sec. This 
corresponds to parallax effect for Solar System Body.

We do not see any OT at the aftergow canditate position (Xu et al.,
GCNC 17829, 17832; Mao et al., GCNC 17830; Littlejohns et al., GCNC 17831;
Moskvitin GCN 17834) with same limit (3 sigma).

We have only one alert image in each telescope because MASTER telescope 
recieved new MAXI correction of the error box and X-ray Transient leave 
the MASTER FOV during alert observations.

But we have observation this X-ray aftergrow position before last 
trigger activated by previouse Fermi (trigger number 451674501, 25 apr 
2015) and during regular synoptic survey (MASTER-Tunka,  ~ 2 days after 
trigger).

Preliminary results:

Id     Pro.type    Date        time    Exp.time Limit Filt. Site
                               Starting         (3sigma)

759597  SumSurvey 2015-05-20  17:02:11 480 20.1 W Tunka
1458076 MaxiAlert 2015-05-18  22:35:35  180  17.1  P/  SAAO
1458345 MaxiAlert 2015-05-18  22:35:43 180 18.5 P|   Kislovodsk
823020  FermiInsp 2015-04-25  20:11:41  180  19.9  W    Kislovodsk

Where W - unfiltered, P - polarization unfiltered. All magnitude 
calculated with respect to hundrends USNO B stars  with calibration:
  m = 0.2B + 0.8R .


At the Tunka Survey we see marginaly faint (~2 sigma) object on the X-ray 
position (Sbarufatti et al., GCN 17827). But this is may be noice. We have 
a lot of images in MASTER NET Data Base imaging last 
several years with   Swift XRT error box. No object we see on this place 
with 20.5 mag limit on first overview (since 2010).

The message may be cited.


GRB_name: GRB150518A
Detection_method: AMI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17839
SUBJECT: GRB 150518A: AMI 15 GHz detection of possible radio counterpart
DATE:    15/05/21 14:46:27 GMT
FROM:    Gemma Anderson at U of Oxford  <Gemma.Anderson@physics.ox.ac.uk>

G. E. Anderson, K. Mooley, R. P. Fender, T. D. Staley (University of Oxford),
A. J. van der Horst (George Washington University), A. Rowlinson (CASS)

We observed the XRT position of GRB 150518A discovered by MAXI
(Sbarufatti et al., GCN  17827, Kawamuro et al., GCN 17825) at 15 GHz
with the Arcminute Microkelvin Imager (AMI-LA) starting on
2015 May 20.962 to 21.128 UT, corresponding to 2.1 days post-burst
(Golenetskii et al., GCN 17837). On this date we detected a radio source
coincident with the position of the optical counterpart (Xu et al., GCN 17829)
with a preliminary flux of 0.19 +/- 0.04 mJy. There are no catalogued radio
sources at this position.

An earlier observation was conducted on 2015 May 19.975 to 20.142 UT,
corresponding to 1.1 days post-burst, yielding a 3 sigma flux upper limit
of 0.13 mJy.

Further AMI monitoring is planned. We thank the AMI staff for scheduling these observations.


GRB_name: GRB150518A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17840
SUBJECT: GRB 150518A:  Mondy optical observations
DATE:    15/05/21 16:49:28 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI),  E. Klunko (ISTP), A. Volnova (IKI), I. Korobtsev 
(ISTP),  A. Pozanenko (IKI) report on behalf of larger GRB follow-up 
collaboration:

We observed the field of the MAXI/GSC GRB 150518A (Kawamuro, et al., GCN 
17825) with AZT-33IK telescope of Sayan observatory (Mondy) starting on 
May, 20 (UT) 16:50:47. We obtained several images in R-filter of 120 s 
exposure. The optical afterglow candidate (Xu et al., GCN 17829)  which 
coincides with SDSS J153648.25+161946.9 galaxy is clearly detected. 
Photometry of the galaxy is following

Date       UT start   t-T0     Filter   Exp.    OT    Err.
                       (mid, days)       (s)

2015-05-20 16:50:47   1.81150  R        20*120  21.22 0.1

Photometry is based on SDSS DR9 stars:

SDSS9_id            R(Lupton)
J153646.11+161904.1    17.65
J153638.21+162002.8    18.41
J153637.55+162040.3    17.10
J153645.59+162055.5    16.35


GRB_name: GRB150518A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17841
SUBJECT: GRB 150518A: MITSuME Akeno Optical observation
DATE:    15/05/21 17:36:01 GMT
FROM:    Taketoshi Yoshii at Tokyo Tech  <yoshii.t.ac@m.titech.ac.jp>

S.Harita, T.Fujiwara, T. Yoshii, Y. Saito, Y. Tachibana, H. Ohuchi, Y. Yano,
S. Kurita, Y.Ono, Y.Muraki, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:

We observed the XRT-UVOT enhanced position of GRB150518A (T.Kawamuro et al., GCN Circular #17825) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan.

The observation started on 2015-05-19 11:08:33 UT (~13.5 h after the burst).
We detected the previously reported optical afterglow of GRB150518A (B.Sbarufatti et al., GCN Circular #17827) in the Rc and Ic band.
Although estimated magnitude of Ic band has large error, we could find a faint point source.

We obtained following limits for the magnitudes.

T0+[sec]      MID-UT      T-EXP[sec]         g'           Rc           Ic
------------------------------------------------------------------------------------------------
  48379     13:43:24          4380           >20.7      20.4+/-0.3     19.7+/-0.43
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration


GRB_name: GRB150518A
Detection_method: VLA Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17859
SUBJECT: GRB 150518A: 6.0 GHz VLA detection
DATE:    15/05/21 22:21:08 GMT
FROM:    Atish Kamble at CfA/Harvard  <akamble@cfa.harvard.edu>

Atish Kamble, Alicia Soderberg and Raffaella Margutti (Harvard University)
report:

We observed the position of the soft-long GRB 150518A (Kawamuro et al., GCN
17825) with the Karl G. Jansky Very Large Array (VLA) beginning on 2015 May
21.12 UT (2.23 days after the burst) at the mean frequency of 6.0 GHz. In
this hour long observation, we detect a faint radio source at the position:

RA: 15 36 48.25
DEC: 16 19 46.82

with an average positional uncertainty of 0.01 arcsec. The VLA is currently
operating in BnA configuration. The radio afterglow position is consistent
with that reported by the Swift-XRT (Sbarufatti et al. GCN 17827).

We measure a 6.0 GHz flux density of the afterglow to be ~222 +/- 7
microJy. This flux density is comparable to that reported by the Arcminute
Microkelvin Imager (Anderson et al. GCN 17839).

Further multiband observations are planned.

We thank the VLA staff for quickly executing these observations.

[GCN OPS NOTE(21may15): Per author's request, the author list was added.]


GRB_name: GRB150518A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17860
SUBJECT: GRB 150518A: MAXI-GSC further analysis
DATE:    15/05/22 16:18:17 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

T. Sakamoto (AGU), M. Serino (RIKEN), S. Nakahira (JAXA), H. Negoro (Nihon U.), 
S. Ueno, H. Tomida, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA), 
T. Mihara, M. Sugizaki, M. Shidatsu, J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN), 
N. Kawai, T. Yoshii, Y. Tachibana (Tokyo Tech), 
A. Yoshida, Y. Kawakubo, H. Ohtsuki (AGU), 
H. Tsunemi, R.Imatani (Osaka U.), 
M. Nakajima, K. Tanaka, T. Masumitsu (Nihon U.), 
Y. Ueda, T. Hori, T. Kawamuro (Kyoto U.), 
Y. Tsuboi, S. Kanetou (Chuo U.), 
M. Yamauchi, D. Itoh (Miyazaki U.), 
K. Yamaoka (Nagoya U.), M. Morii (ISM)

We report further analysis using the MAXI/GSC data of MAXI GRB 150518A 
(Kawamuro et al. GCN Circ. 17825).  The MAXI GSC light curve shows a constant 
flux during the scan.  Due to a poor statistics, it is hard to claim a 
variability in the light curve.  The MAXI light curve plot is available from 
the following URL.

http://maxi.riken.jp/grbs/150518a/

The GSC spectrum (2-20 keV) using the data from 21:42:00 UT to 21:42:49 UT 
is best fit by a simple power-law model.  The best fit power-law photon index 
is 1.3 +- 0.4.  The column density is not well constrained from the GSC spectrum.  
The unabsorbed flux in the 2-20 keV band is (1.0 +- 0.3) x 10^-8 erg/cm2/s.  
From this best fit model, the unabsorbed X-ray flux in the 0.3-10 keV band 
(Swift/XRT energy band) is (7.9 +- 2.4) x 10^-9 erg/cm2/s.  No emission was 
detected from the GRB position during the next scan starting from 23:11 UT at 
the 1 sigma upper limit of ~9 mCrab.

Using the possible host galaxy redshift of 0.256 (Xu et al. GCN Circ. 17832), 
the X-ray luminosity at the time of the MAXI detection is 1.7 x 10^48 erg/s (2-20 keV) 
and 1.3 x 10^48 erg/s (0.3-10 keV).  Assuming the onset of this GRB is the 
detection by Konus-Wind (Golenetskii et al. GCN Circ. 17837), we found that 
the MAXI luminosity around ~1000 sec after this onset is consistent with a typical 
early afterglow emission seen by Swift/XRT (e.g., Racusin et al. 2011, ApJ, 738, 138).

On the other hand, if the possible emission seen by the Konus-Wind data around 
the MAXI detection is real, the duration of GRB 150518A can be >1000 s.  As we 
reported above, the MAXI GSC spectrum is rather hard for an afterglow.  In this 
case, this GRB can be classified as an ultra-long GRB.  

All the quoted errors are at the 90% confidence level.  The assumed cosmological 
parameters are H0 = 71 km s^-1 Mpc^-1, Omega_m = 0.27 and Omega_lamda = 0.73.


GRB_name: GRB150518A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17861
SUBJECT: GRB 150518A: Continued RATIR optical observations
DATE:    15/05/22 20:44:31 GMT
FROM:    Owen Littlejohns at Az State U  <olittlej@asu.edu>

Owen Littlejohns (ASU), Nat Butler (ASU), Alan M. Watson (UNAM),
Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer
(UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC),
Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Eleonora Troja
(GSFC), Enrico Ramirez-Ruiz (UCSC), Jos A. de Diego (UNAM), Leonid
Georgiev (UNAM), Jess Gonzlez (UNAM), Carlos Romn-Ziga (UNAM),
Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:

We continued to observe the field of GRB 150518A (Kawamuro, et al., GCN
17825) with the Reionization and Transients Infrared Camera (RATIR;
www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio
Astronmico Nacional on Sierra San Pedro Mrtir for two further epochs.

Our first full epoch now extends from 2015/05 20.15 to 2015/05 20.47 UTC
(29.94 to 37.69 hours after the BAT trigger), obtaining a total of 6.04
hours exposure in the r, i and z bands.

For the previously reported SDSS galaxy (Xu, et al., GCN 17829; Mao,
et al., GCN 17830; Littlejohns, et al., GCN 17831), in comparison with
the SDSS DR9, we obtain the following detections:


  r     21.27 +/- 0.04
  i     21.02 +/- 0.04
  z     20.53 +/- 0.24

The second epoch of RATIR observations ranged from 2015/05 21.21 to
2015/05 21.45 UTC (55.33 to 61.20 hours after the BAT trigger),
obtaining a total of 3.59 hours exposure in the r and i bands, and
1.07 hours in the z band. For the same SDSS galaxy, again in
comparison with the SDSS DR9, we obtain the following detections
and upper limit (3-sigma):

  r     21.40 +/- 0.08
  i     21.08 +/- 0.08
  z     > 17.70

The third epoch of RATIR observations was from 2015/05 22.15 to
2015/05 22.47 UTC (77.99 to 85.61 hours after the BAT trigger),
obtaining a total of 6.04 hours exposure in the r, i and z bands.
In this epoch, we obtain the following detections of the SDSS galaxy:

  r     21.34 +/- 0.04
  i     21.08 +/- 0.04
  z     20.80 +/- 0.35

These magnitudes are in the AB system and are not corrected for
Galactic extinction in the direction of the GRB.

Combining the r and i band observations from the second and third
epochs, we find marginal evidence that the source has faded, changing
by 0.07 +/-0.04 magnitudes when compared to the first epoch of RATIR
observations (Littlejohns, et al., GCN 17831). During the full first
epoch of observations, we also observed marginal (1-sigma) evidence
for fading by 0.05 magnitudes in the r and i bands. Finally, we note
that image subtraction between the third and first epochs, in both r
and i band, yield positive residuals in the Swift-XRT error circle at
the 1-sigma level.

We thank the staff of the Observatorio Astronmico Nacional in San
Pedro Mrtir.


GRB_name: GRB150523A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17863
SUBJECT: GRB 150523A: Fermi GBM detection
DATE:    15/05/23 15:02:01 GMT
FROM:    Hoi-Fung Yu at MPE  <sptfung@mpe.mpg.de>

H.-F. Yu (MPE) reports on behalf of the Fermi GBM Team:

"At 09:29:48.08 UT on 23 May 2015, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 150523A (trigger 454066191 / 150523396).

The on-ground calculated location, using the GBM trigger
data, is RA = 121.2, Dec = -37.3 (J2000 degrees, equivalent 
to 08h 05m, -37d 20'), with an uncertainty of 1.7 degrees 
(radius, 1-sigma containment, statistical only; there is 
additionally a systematic error which is currently estimated 
to be 2 to 3 degrees).

The trigger resulted in an Autonomous Repoint Request (ARR) 
that was accepted and the spacecraft slewed to the GBM in-flight 
location. The initial angle from the Fermi LAT boresight
is 22 degrees.

The GBM light curve consists of two pulses with a duration (T90) 
of about 74.2 s (50-300 keV). The time-averaged spectrum 
from T0-4.352 s to T0+40.705 s is best fit by a power law function 
with an exponential high-energy cutoff. The power law index 
is -0.64 +/- 0.03 and the cutoff energy, parameterized as Epeak, 
is 574 +/- 24 keV.

The event fluence (10-1000 keV) in this time interval is
(3.57 +/- 0.05)E-05 erg/cm^2. The 1.024-sec peak photon flux 
measured starting from T0+32.769 s in the 10-1000 keV band
is 8.34 +/- 0.25 ph/s/cm^2.

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


GRB_name: GRB150523A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17864
SUBJECT: GRB 150523A: Fermi-LAT detection
DATE:    15/05/23 18:20:18 GMT
FROM:    Elisabetta Bissaldi at U.Innsbruk/IAPP  <Elisabetta.Bissaldi@uibk.ac.at>

E. Bissaldi (INFN Bari), G. Vianello (Stanford University)
and M. Yassine (LUPM) report on behalf of the Fermi-LAT team:



At 09:29:48.08 UT on May 23, 2015, Fermi-LAT detected
high-energy emission from GRB 150523A, which was also
detected by Fermi-GBM (trigger 454066191 / 150523396)
(Yu et al., GCN #17863).
The best LAT on-ground location is found to be

RA, Dec = 115.36, -45.40 (J2000)

with an error radius of 0.10 deg (90 per cent containment,
statistical error only).
This was 26 deg from the LAT boresight at the time of
the trigger and triggered an autonomous
repoint of the spacecraft.

The data from the Fermi-LAT show a significant increase
in the event rate that is spatially and temporally
correlated with the trigger with high significance.
The highest-energy photon is a 7 GeV event, which is
observed 118 s after the GBM trigger.

A Swift ToO has been requested for this burst.

The Fermi-LAT point of contact for this burst is
Elisabetta Bissaldi (Elisabetta.Bissaldi@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.


GRB_name: GRB150523B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17865
SUBJECT: GRB 150523B: Swift ToO observations
DATE:    15/05/23 18:47:19 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift has initiated a ToO observation of the Fermi/LAT GRB 150523B. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020520

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the Fermi/LAT event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a 
GCN Circular after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

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


GRB_name: GRB150523A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17866
SUBJECT: GRB 150523A Swift-XRT afterglow detection
DATE:    15/05/23 22:29:30 GMT
FROM:    Angelica Vargas at PSU/Swift  <avargas@swift.psu.edu>

A.P. Beardmore (U. Leicester), A. Amaral-Rogers (U. Leicester), P.
D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. D'aï¿½ (INAF-IASFPA), D.N.
Burrows (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU) and P.A.
Evans (U. Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has performed follow-up observations of the
Fermi/LAT-detected burst GRB 150523A collecting 1.4 ks of Photon
Counting (PC) mode data between T0+33.0 ks and T0+34.3 ks. 

An uncatalogued X-ray source is detected and is above the RASS limit,
and is therefore likely the GRB afterglow.  The position of this source
is RA, Dec=115.2859, -45.4209 which is equivalent to:

RA (J2000): 07:41:8.62
Dec(J2000): -45:25:15.1

with an uncertainty of 3.7 arcsec (radius, 90% confidence).  This
position is 3.4 arcmin from the Fermi/LAT position.  The light curve is
consistent with a constant source of mean count rate 1.2e-01 ct/sec. A
power-law fit gives an index of -1.41 (+4.59, -0.05).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.71 (+0.29, -0.21). The
best-fitting absorption column is  consistent with the Galactic value
of 3.5 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum  is 4.5 x 10^-11 (5.9 x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      3.5 (+/-1.3) x 10^21 cm^-2
Galactic foreground: 3.5 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.71 (+0.29, -0.21)

The results of the XRT-team automatic analysis of the likely afterglow
are at http://www.swift.ac.uk/ToO_GRBs/00020520/index_1.php.
The results of the full analysis of the XRT observations are available
at http://www.swift.ac.uk/ToO_GRBs/00020520.

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


GRB_name: GRB150523A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17868
SUBJECT: GRB 150523A: LCOGT Cerro-Tololo optical afterglow candidate
DATE:    15/05/24 07:24:01 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

S. Dichiara, C. Guidorzi (U. Ferrara), C.G. Mundell (Bath U.),
A. Gomboc (U. Ljubljana) on behalf of a larger collaboration report:

The 1-m LCOGT unit in Cerro Tololo began observing Fermi GBM
and LAT GRB 150523A (Yu et al GCN 17863; Bissaldi et al. GCN 17864)
on May 23 at 23:17 UT (~13.8 hours after the burst trigger)
with SDSS r and i filters.
Inside the Swift-XRT error circle (Beardmore et al GCN 17866)
we detect an uncatalogued object at the following position:

RA(J2000) =   07:41:08.68
Dec(J2000)=  -45:25:12.3

with an uncertainty of ~1" and a magnitude of R=20.2 +-0.1 calibrated
against nearby USNOB-1 stars. Presently we cannot establish whether
the source is fading.


GRB_name: GRB150523A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17869
SUBJECT: GRB 150523A: LCOGT FTS afterglow confirmation
DATE:    15/05/25 10:06:33 GMT
FROM:    Simone Dichiara at Ferrara U/Italy  <dichiara@fe.infn.it>

S. Dichiara, C. Guidorzi (U. Ferrara), S.Kobayashi (LJMU),
C.G. Mundell (U. Bath), A. Gomboc (U. Ljubljana) on behalf
of a larger collaboration report:

On May 24 we re-observed GRB 150523A (Yu et al GCN 17863;
Bissaldi et al. GCN 17864) using the 2-m Faulkes Telescope South
(FTS) with SDSS r and i filters, starting from 08:53 UT (~23.4 hours
post burst). Compared with our previous report (Dichiara et al.
GCN 17868) the optical candidate appears to have significantly
faded, as follows:

Mid time(hrs)    Exp(s)       Filter   Magnitude
-----------------------------------------------
13.87            10x120          r'    20.45 +- 0.15
23.69            10x120          r'    21.20 +- 0.22
-----------------------------------------------

The corresponding average power-law decay index is 1.3 +- 0.5.
Magnitudes are calibrated against USNOB-1 nearby stars.
We therefore confirm the afterglow nature of the optical
candidate previously reported.


GRB_name: GRB150523A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17870
SUBJECT: Konus-Wind observation of GRB 150523A
DATE:    15/05/25 12:47:10 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

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

The long-duration GRB 150523A
(Fermi-GBM detection: Yu, GCN Circ. 17863;
Fermi-LAT detection: Bissaldi, et al., GCN Circ. 17864)
triggered Konus-Wind at T0=34189.641 s UT (09:29:49.641).

The burst light curve consists of two pulses
with a total duration of ~36 s.
The emission is seen up to ~10 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB150523_T34189/

As observed by Konus-Wind, the burst
had a fluence of 4.44(-0.69,+0.71)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+31.792 s,
of 5.52(-1.52,+1.53)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+41.216 s)
is best fit in the 20 keV - 12 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.31(-0.14,+0.16),
the high energy photon index beta = -2.66(-0.99,+0.32),
the peak energy 399(-42,+52) keV
(chi2 = 94/97 dof)

The spectrum near the maximum count rate
(measured from T0+24.832 to T0+33.024 s)
is best fit in the 20 keV - 12 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.35(-0.15,+0.17),
the high energy photon index beta = -2.66(-1.35,+0.34),
the peak energy 389(-48,+58) keV
(chi2 = 104/97 dof)

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


GRB_name: GRB150513A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17871
SUBJECT: GRB 150513A: request for X-ray follow up
DATE:    15/05/25 23:53:47 GMT
FROM:    Remo Rufinni at ICRA  <ruffini@icra.it>

R. Ruffini, C. L. Bianco, M. Enderli, M. Kovacevic, M. Muccino, G. B.
Pisani, J. A. Rueda, Y. Wang reports:

The observation of high-energy emission from GRB 150513A by Fermi-LAT
[1] clearly points to a binary-driven hypernova (BdHN) nature of the
source [2], in spite of the missing follow-up from Swift/XRT and UVOT
due to a Sun observing constraint which will last until the 28th of May
[3].

BdHNe have a standard behavior in the late X-ray luminosity [4,5,6],
thus we expect the X-ray emission of GRB 150513A to follow such a
behavior as well.

Assuming that the X-ray luminosity of GRB 150513A is comparable with
the BdHN prototypical one of GRB 090618 (GRB 130427A), a detection by
Swift/XRT of GRB 150513A on the 28th of May implies an upper limit for
its redshift z<0.8 (z<2).

Therefore, we strongly encourage observation by Swift/XRT of GRB
150513A from the 28th of May on. This would give a fundamental
information on the nature of this source, despite the absence of data
between May 13th and May 28th.

References:
[1] Kocevski et al. 2015, GCN 17812
[2] Ruffini et al. 2015, ApJ, 798, 10R
[3] Kocevski et al. 2015, GCN 17810
[4] Ruffini et al. 2014, A&A, 565, L10
[5] Pisani et al. 2013, A&A, 552, L5
[6] Ruffini et al. 2014, A&A, 569, A39


GRB_name: GRB150523A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17872
SUBJECT: GRB 150523A: Swift/UVOT Detection
DATE:    15/05/26 17:15:00 GMT
FROM:    Frank Marshall at GSFC  <femarsha@khamseen.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC) and A. Vargas (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150523A
32968 s after the LAT trigger (Bissaldi et al. GCN Circ. 17864).
A source consistent with the XRT position (Beardmore et al. GCN Circ. 17866)
and the optical afterglow position (Dichiara et al. GCN Circ. 17868 and 17869)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  07:41:08.67 = 115.28613 (deg.)
    Dec (J2000) = -45:25:12.4  = -45.42011 (deg.)
with an estimated uncertainty of 0.78 arc sec. (radius, 90% confidence).

Preliminary detections using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: 

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

white            33590        39627         1150         21.83 +/- 0.24
v                34212        40619         1433        >20.5
u                32968        44748         2077        >20.5

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.30 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB150523A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17873
SUBJECT: GRB 150523A: Swift ToO observations
DATE:    15/05/27 04:00:17 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift has initiated a ToO observation of the Fermi/LAT GRB 150523A. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020521

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the Fermi/LAT event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a 
GCN Circular after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

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


GRB_name: GRB150527A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17874
SUBJECT: GRB 150527A: Swift detection of a burst
DATE:    15/05/27 07:03:59 GMT
FROM:    Phil Evans at U of Leicester  <pae9@star.le.ac.uk>

P. A. Evans (U Leicester), S. D. Barthelmy (GSFC),
A. Y. Lien (GSFC/UMBC), K. L. Page (U Leicester) and
T. N. Ukwatta (LANL) report on behalf of the Swift Team:

At 06:48:55 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 150527A (trigger=641698).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 288.958, +4.194 which is 
   RA(J2000) = 19h 15m 50s
   Dec(J2000) = +04d 11' 38"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a multi-peaked
structure with a duration of about 40 sec.  The peak count rate
was ~4000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 06:49:57.6 UT, 61.8 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 288.9599, 4.2013 which
is equivalent to:
   RA(J2000)  = 19h 15m 50.39s
   Dec(J2000) = +04d 12' 04.7"
with an uncertainty of 2.3 arcseconds (radius, 90% containment). This
location is 27 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.  We
cannot determine whether the source is fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 5.67
x 10^21 cm^-2 (Willingale et al. 2013). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 67 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. Because of the density of catalogued stars, further
analysis is required to report an upper limit for any afterglow in the
sub-image. 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. No correction has been made for the large, but uncertain extinction
expected. 

Burst Advocate for this burst is P. A. Evans (pae9 AT star.le.ac.uk). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB150523A
Detection_method: Suzaku WAM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17875
SUBJECT: GRB 150523A: Suzaku WAM observation of the prompt emission
DATE:    15/05/27 07:29:45 GMT
FROM:    Makoto Tashiro at Saitama U/Swift  <tashiro@phy.saitama-u.ac.jp>

T. Fujinuma,  M. Tashiro, Y. Terada, T. Yasuda, S. Takeda,
T. Nagayoshi, J. Enomoto, S. Nakaya, S. Matsuoka, S. Yabe (Saitama U.),
M. Yamauchi, N. Ohmori, R. Kinoshita (Univ. of Miyazaki),
W. Iwakiri (RIKEN), K. Yamaoka (Nagoya U.), S. Sugita (Ehime U.),
M. Ohno, T. Kawano, Y. Fukazawa (Hiroshima U.),
Y. E. Nakagawa, M. Kokubun, T. Takahashi (ISAS/JAXA),
Y. Urata (NCU), K. Nakazawa, K. Makishima (Univ. of Tokyo)
on behalf of the Suzaku WAM team, report:

The long GRB 150523A(Fermi GBM trigger: Yu et al.,GCN 17863;
Fermi-LAT detection:Bissaldi et al.,GCN 17864;
Konus-Wind observation: Golenetskii et al.,GCN 17870) triggered the 
Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range
of 50 keV - 5 MeV at 09:29:50 UT (=T0).

The observed light curve shows double-peaked structure starting at
T0-4 s, ending at T0+33 s, with a duration (T90) of about 32 seconds.
The fluence in 100 - 1000 keV was 1.81(+0.23/-0.25) x 10^-5 erg/cm^2.
The 1-s peak flux measured from T0+31 s was
3.52(+0.19/-0.34) photons/cm^2/s in the same energy range.

Preliminary result shows that the time-averaged spectrum from T0-4s
to T0+33s is well fitted by a power-law with exponential cutoff model:
dN/dE ~  E^{-alpha} * exp(-(2-alpha)*E/Epeak) with
alpha    0.70(+0.48/-0.56), and
Epeak    417(+56/-41) keV (chi^2/d.o.f. = 61.26/52).

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

The light curves with 1-sec time resolution for this burst will be 
appeared at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html


GRB_name: GRB150527A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17876
SUBJECT: GRB 150527A: RATIR Afterglow Detection
DATE:    15/05/27 08:04:18 GMT
FROM:    Nat Butler at Az State U  <natbutler@asu.edu>

Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William
H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB),
J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara
(ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), Jos A. de Diego (UNAM), Leonid Georgiev (UNAM), Jess
Gonzlez (UNAM), Carlos Romn-Ziga (UNAM), Neil Gehrels (GSFC), and
Harvey Moseley (GSFC) report:

We observed the field of GRB 150527A (Evans, et al., GCN 17874) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the
1.5m Harold Johnson Telescope at the Observatorio Astronmico Nacional on
Sierra San Pedro Mrtir from 2015/05 27.29 to 2015/05 27.32 UTC (13.2 to
54.6 minutes after the BAT trigger), obtaining a total of 0.58 hours
exposure in the r, i, and z bands.

A source is detected within the Swift-XRT error circle.  In comparison with
the USNO-B1 catalog, we obtain the following detections and upper limit
(3-sigma):

  r     21.17 +/- 0.10
  i     20.83 +/- 0.14
  z     > 19.50

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.  Additional observations are
ongoing.

We thank the staff of the Observatorio Astronmico Nacional in San Pedro
Mrtir.


GRB_name: GRB150527A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17877
SUBJECT: GRB 150527A: LCOGT McDonald observations
DATE:    15/05/27 09:02:38 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

J. Japelj (U. Ljubljana), C. Guidorzi (U. Ferrara), C.G. Mundell (U. Bath),
S. Kobayashi (LJMU), A. Gomboc (U. Ljubljana) on behalf of a
larger collaboration report:

The 1-m LCOGT McDonald unit began observing Swift GRB 150527A
(Evans al GCN 17874) on May 27 at 06:56:33 UT (~7.6 minutes
after the burst trigger) with SDSS r and i filters.
Inside the Swift-XRT error circle we provide conservative
limits on detection down to the following limiting magnitudes:

Mid Time      Exposure       Filter       Magnitude
(s)           (s)
---------------------------------------------------
  795          5x120          r'           > 19.5
1500          5x120          i'           > 18.3
---------------------------------------------------

These values are compatible with the source reported by RATIR
(Butler et al. GCN 17876), although no information about its
position is reported.
We note the presence of a faint source in our coadded image
with i'=20.6 +- 0.4 mag at the following position:
RA(J2000)=19:15:50.31, Dec(J2000)= +04:12:05.0.
However, we caution that the field is crowded, Galactic
dust extinction towards this field is high, A_V = 2.7 mag
(Schlafly et al. 2011).
Calibration is done against nearby USNOB-1 stars.


GRB_name: GRB150527A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17878
SUBJECT: GRB 150527A: Fermi GBM observation
DATE:    15/05/27 14:29:39 GMT
FROM:    Hoi-Fung Yu at MPE  <sptfung@mpe.mpg.de>

H.-F. Yu (MPE) reports on behalf of the Fermi GBM Team:

"At 06:47:08.70 UT on 27 May 2015, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 150527A (trigger 454402031 / 150527283), 
which was also detected by Swift (Evans et al. 2015, GCN 17874).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight is 89 degrees.

The GBM light curve shows one single pulse with a duration (T90) 
of about 9.2 s (50-300 keV). The time-averaged spectrum from 
T0-3.072 s to T0+7.168 s is best fit by a power law function 
with an exponential high-energy cutoff. The power law index 
is -0.76 +/- 0.20 and the cutoff energy, parameterized as Epeak, 
is 319 +/- 97 keV.

The event fluence (10-1000 keV) in this time interval is
(2.2 +/- 0.4)E-06 erg/cm^2. The 1.024-sec peak photon flux 
measured starting from T0+2.304 s in the 10-1000 keV band
is 2.1 +/- 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: GRB150527A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17879
SUBJECT: GRB 150527A: Enhanced Swift-XRT position
DATE:    15/05/27 16:33:45 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 2996 s of XRT Photon Counting mode data and 4 UVOT
images for GRB 150527A, 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 = 288.95986, +4.20196 which is equivalent
to:

RA (J2000): 19h 15m 50.37s
Dec (J2000): +04d 12' 07.0"

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


GRB_name: GRB150527A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17880
SUBJECT: GRB 150527A: Swift-BAT refined analysis
DATE:    15/05/27 16:47:04 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), P. A. Evans (U Leicester), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+711 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 150527A (trigger #641698)
(Evans, et al., GCN Circ. 17874).  The BAT ground-calculated position is
RA, Dec = 288.962, 4.195 deg, which is 
   RA(J2000)  =  19h 15m 50.9s 
   Dec(J2000) = +04d 11' 41.0" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 99%.
 
The mask-weighted light curves shows a multi-peak event starting at ~T-45 sec,
with the brightest peak at ~T-14, and ending at T+25 sec.
T90 (15-350 keV) is 112 +- 80 sec (estimated error including systematics).
 
The time-averaged spectrum from T-111.44 to T+16.56 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.69 +- 0.10.  The fluence in the 15-150 keV band is 3.1 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T-7.94 sec in the 15-150 keV band
is 0.3 +- 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/641698/BA/


GRB_name: GRB150527A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17881
SUBJECT: GRB150527A: REM - NIR afterglow
DATE:    15/05/27 18:21:19 GMT
FROM:    Eliana Palazzi at IASF/CNR,Bologna  <palazzi@iasfbo.inaf.it>

L. Nicastro, E. Palazzi, A. Rossi (INAF/IASF Bologna), D. Fugazza (INAF/OAB) on 
behalf of the REM team:

We observed the field of the GRB150527A (Evans et al., GCN 17874) 
simultaneously in the optical (griz) and near infrared (H) bands with the 60-cm 
robotic telescope REM at La Silla Observatory (Chile). The observations started 
about 1 min after the GRB trigger.

An uncatalogued source in the enhanced XRT error box (Evans et al., GCN 
17879) is detectedi, only in the H images, at the coordinates:

RA(J2000) = 19:15:50.31
DEC(J2000) = +04:12:06.1

Possibly this is the same source mentioned by Butler et al. (GCN 17876).

A very preliminary photometry, calibrated against 2MASS, indicates that 
the object faded from H = 14.8 +/- 0.2 in the first image to H = 15.2 +/- 
0.2 about 5 min later. Thus we identify this source as the NIR afterglow 
of the burst.


GRB_name: GRB150527A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17882
SUBJECT: GRB 150527A: Swift/UVOT Upper Limits
DATE:    15/05/27 21:46:10 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld@ucl.ac.uk>

A. A. Breeveld (UCL-MSSL) and P. A. Evans (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150527A 68 
s after the BAT trigger (Evans et al., GCN Circ. 17874).
No optical afterglow consistent with the enhanced XRT position (Evans et 
al. GCN Circ. 17879) or with the RATIR or REM sources (Butler et al., 
GCN Circ. 17876 and Nicastro et al., GCN Circ. 17881) is detected in the 
initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system 
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding 
chart (FC) exposure and subsequent exposures are:

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

white_FC            68          218          147         >20.2
u_FC               280          523          240         >19.1
white            10385        11927         1542         >21.2
v                 4315         4515          197         >18.8
b                 3700        10380         1082         >20.8
u                  280         6271          623         >19.6
w1                5920         6120          197         >19.4
w2                4110        12019          281         >19.8

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening of E(B-V) = 0.97 in the direction of the 
burst (Schlegel et al. 1998). We note however that the value for 
extinction could be unreliable at this position.


GRB_name: GRB150527A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17883
SUBJECT: GRB 150527A: MITSuME Okayama upper limits
DATE:    15/05/28 00:20:58 GMT
FROM:    Daisuke Kuroda at OAO/NAOJ  <dikuroda@oao.nao.ac.jp>

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

We observed the field of GRB 150527A (Evans et al., GCNC 17874)
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 2015-05-27 12:57:14 UT (~6.1 h after the burst).
We could not detect the previously reported afterglow (Butler et al., GCNC
17527) in all the three bands.

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

#T0+[day]  MID-UT    T-EXP[sec]   g'     Rc     Ic
-----------------------------------------------------
0.29760    13:57:27    5760.0   >19.5  >19.2  >18.3
-----------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]


GRB_name: GRB150527A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17884
SUBJECT: GRB 150527A: Swift-XRT refined Analysis
DATE:    15/05/28 07:04:04 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. Amaral-Rogers (U. Leicester), A. D'a (INAF-IASFPA), A. Maselli 
(INAF-IASFPA), A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU),
D.N. Burrows (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester),
K.L. Page (U. Leicester) and P.A. Evans report on behalf of the
Swift-XRT team:

We have analysed 3.7 ks of XRT data for GRB 150527A (Evans et al. GCN
Circ. 17874), from 47 s to 22.7 ks after the  BAT trigger. The data
comprise 598 s in Windowed Timing (WT) mode (the first 8 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Evans et
al. (GCN Circ. 17879).

The late-time light curve (from T0+3.7 ks) can be modelled with a
power-law decay with a decay index of alpha=0.9 (+0.6, -0.4).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.0 (+0.4, -0.3). The
best-fitting absorption column is  1.2 (+0.5, -0.4) x 10^22 cm^-2, in
excess of the Galactic value of 5.7 x 10^21 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 4.8 x 10^-11 (9.5 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.2 (+0.5, -0.4) x 10^22 cm^-2
Galactic foreground: 5.7 x 10^21 cm^-2
Excess significance: 2.7 sigma
Photon index:      2.0 (+0.4, -0.3)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00641698.

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


GRB_name: GRB150527A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17885
SUBJECT: Konus-Wind observation of  GRB 150527A
DATE:    15/05/28 17:00:31 GMT
FROM:    Anastasia Tsvetkova at Ioffe Institute  <tsvetkova@mail.ioffe.ru>

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

The long-duration GRB 150527A (Swift-BAT trigger #641698:
Evans, et al., GCN Circ. 17874; Lien, et al., GCN Circ. 17880;
Fermi-GBM detection: Yu, GCN Circ.17878)
was detected by Konus-Wind in the waiting mode.

The burst light curve shows two emission episodes:
the first episode (from ~T0(BAT)-108 s to ~T0(BAT)-99 s) triggered GBM,
and the second (from ~T0(BAT)-22 s to ~T0(BAT)+4s), which triggered BAT.

As observed by Konus-Wind, the burst had a fluence of
6.09(-0.62,+0.76)x10^-6 erg/cm2 and a 2.944-s peak flux,
measured from ~T0(BAT)-13 s, of 3.10(-0.61,+0.65)x10^-7 erg/cm2/s
(both in the 20 - 1000 keV energy range).

Fitting the K-W 3-channel time-integrated spectrum
(measured from ~T0(BAT)-108 s to ~T0(BAT)+4 s)
by a simple power-law model yields the photon index
-2.20(-0.10,+0.10), chi2=0.88/1 dof.

Modelling the 3-channel spectrum near the peak count rate
(from ~T0(BAT)-13 s to ~T0(BAT)-10 s)
by the cutoff power law yields the following model parameters:
the photon index alpha = -1.62(-0.31,+0.92),
and the peak energy Ep = 107(-40,+100) keV.

All the quoted errors are estimated at the 1 sigma confidence level.
All the presented results are preliminary.

The K-W light curve of this burst is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB150527A/


GRB_name: GRB150513A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17886
SUBJECT: GRB 150513A: Swift-XRT observations
DATE:    15/05/29 13:16:32 GMT
FROM:    Andy Beardmore at U Leicester  <ab271@leicester.ac.uk>

A. Maselli  (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo
(INAF-OAB), D.N. Burrows (PSU), J.A. Kennea (PSU), B. Sbarufatti
(INAF-OAB/PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester),
C. Pagani (U. Leicester) and A. Y. Lien (GSFC/UMBC) report on behalf of
the Swift-XRT team:

We have analysed  of XRT data for the Swift/BAT-detected burst GRB
150513A (Lien et al. GCN Circ. 17814), collecting 5.0 ks of Photon
Counting (PC) mode data between T0+1309.8 ks and T0+1322.8 ks. 

No X-ray sources have been detected inside or close to the Swift/BAT
error region. The 3-sigma upper limit at the Swift/BAT position is
0.001 ct s^-1, corresponding to a 0.3-10 keV observed flux of 5.8e-14
to  erg cm^-2 s^-1 (assuming a typical GRB spectrum).

The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
http://www.swift.ac.uk/ToO_GRBs/00640584.

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


GRB_name: GRB150530A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17888
SUBJECT: GRB 150530A: Swift detection of a burst
DATE:    15/05/30 11:59:01 GMT
FROM:    Rhaana Starling at U of Leicester  <rlcs1@star.le.ac.uk>

R. L. C. Starling (U Leicester), N. Gehrels (NASA/GSFC),
J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC) and
K. L. Page (U Leicester) report on behalf of the Swift Team:

At 11:42:18 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 150530A (trigger=642018).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 327.523, +57.490 which is 
   RA(J2000) = 21h 50m 06s
   Dec(J2000) = +57d 29' 25"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single peak with
some structure with a duration of about 10 sec.  The peak count rate
was ~2500 counts/sec (15-350 keV). 

The XRT began observing the field at 11:44:00.8 UT, 102.7 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 327.5109, 57.5164 which
is equivalent to:
   RA(J2000)  = 21h 50m 02.61s
   Dec(J2000) = +57d 30' 58.9"
with an uncertainty of 3.3 arcseconds (radius, 90% containment). This
location is 96 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.  We
cannot determine whether the source is fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 1.00
x 10^22 cm^-2 (Willingale et al. 2013). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 106 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 large, but uncertain extinction expected. 

Burst Advocate for this burst is R. L. C. Starling (rlcs1 AT star.le.ac.uk). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB150530A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17889
SUBJECT: GRB 150530A: Enhanced Swift-XRT position
DATE:    15/05/30 15:55:52 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 418 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 150530A, 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 = 327.51297, +57.51681 which is equivalent
to:

RA (J2000): 21h 50m 3.11s
Dec (J2000): +57d 31' 00.5"

with an uncertainty of 2.2 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).

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


GRB_name: GRB150530A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17890
SUBJECT: GRB 150530A: Swift-BAT refined analysis
DATE:    15/05/30 16:15:22 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), R. L. C. Starling (U Leicester), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
 
Using the data set from T-61 to T+242 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 150530A (trigger #642018)
(Strling, et al., GCN Circ. 17888).  The BAT ground-calculated position is
RA, Dec = 327.511, 57.519 deg, which is 
   RA(J2000)  =  21h 50m 02.6s 
   Dec(J2000) = +57d 31' 07.4" 
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 17%.
 
The mask-weighted light curve shows a couple overlapping peaks starting
at ~T-10 sec, peaking at ~T+2 sec, and ending at ~T+40 sec.
T90 (15-350 keV) is 6.62 +- 0.84 sec (estimated error including systematics).
 
The time-averaged spectrum from T-4.21 to T+3.49 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.49 +- 0.11.  The fluence in the 15-150 keV band is 1.8 +- 0.1 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T+0.48 sec in the 15-150 keV band
is 4.1 +- 0.6 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/642018/BA/


GRB_name: GRB150530A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17891
SUBJECT: GRB 150530A: Fermi GBM observation
DATE:    15/05/30 18:45:28 GMT
FROM:    George A. Younes at USRA/NASA/MSFC  <younes.ge@gmail.com>

Yu H.-F. (MPE), Younes G. (USRA at GWU), and Meegan C. (UAH)
report on behalf of the Fermi GBM Team:

"At 11:42:15.61  UT, on 2015 May 30, the Fermi
Gamma-Ray Burst Monitor triggered and located GRB 150530A
(trigger 454678938 / 150530488) which was also detected
by Swift (Starling  et al. 2015, GCN 17888). The GBM on-ground
location is consistent with the Swift position. The angle from the
Fermi LAT boresight is about 46 degrees.

The GBM light curve consists of two peaks with a duration (T90) of
7 s (50-300 keV). The time-averaged spectrum from T0-4.6 s to
T0+6.7 s is well fit by a BAND function with Epeak = 126 +/- 14 keV,
alpha = -0.8 +/- 0.1, and beta = -2.4 +/- 0.2.

The event fluence (10-1000 keV) in this time interval is
(4.1 +/- 0.2)E-06 erg/cm^2. The 1.024-sec peak photon
flux measured starting from T0+2.8 s in the 10-1000 keV
band is 6.7 +/- 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: GRB150530A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17892
SUBJECT: GRB 150530A: Swift/UVOT Upper Limits
DATE:    15/05/30 21:29:27 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld@ucl.ac.uk>

M. De Pasquale (UCL-MSSL) 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 150530A 
106 s after the BAT trigger (Starling et al., GCN Circ. 17888).
No optical afterglow consistent with the XRT position (Goad et al.
GCN Circ. 17889) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding 
chart (FC) exposure and subsequent exposures are:

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

white_FC           106          256          147 >20.1
u_FC               319          562          238 >19.2
white              106         5690          541 >21.0
v                 4465         6101          393 >19.3
b                 3849         5485          393 >20.4
u                  319         5280          435 >19.7
w1                4875         5075          197 >19.5
m2                4670         6306          393 >19.9
w2                4260         5896          393 >20.1

The magnitudes in the table are not corrected for the strong Galactic
extinction due to the reddening of E(B-V) = 1.81 in the direction of
the burst (Schlegel et al. 1998).


GRB_name: GRB150530A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17893
SUBJECT: GRB 150530A: Swift-XRT refined Analysis
DATE:    15/05/30 23:59:04 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), J.A. Kennea (PSU), B.
Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), K.L. Page (U.
Leicester), C. Pagani (U. Leicester), A.P. Beardmore (U. Leicester), V.
D'Elia (ASDC) and R.L.C. Starling report on behalf of the Swift-XRT
team:

We have analysed 9.2 ks of XRT data for GRB 150530A (Starling et al.
GCN Circ. 17888), from 90 s to 22.6 ks after the  BAT trigger. The data
comprise 6 s in Windowed Timing (WT) mode (taken while Swift was
slewing), with the remainder in Photon Counting (PC) mode. The enhanced
XRT position for this burst was given by Goad et al. (GCN Circ. 17889).

The light curve can be modelled with a power-law decay with a decay
index of alpha=0.98 (+/-0.06).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.9 (+/-0.5). The
best-fitting absorption column is  2.2 (+0.9, -0.8) x 10^22 cm^-2, in
excess of the Galactic value of 1.0 x 10^22 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 6.6 x 10^-11 (1.3 x 10^-10) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      2.2 (+0.9, -0.8) x 10^22 cm^-2
Galactic foreground: 1.0 x 10^22 cm^-2
Excess significance: 2.7 sigma
Photon index:      1.9 (+/-0.5)

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 1.6 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x
10^-13 (2.2 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/00642018.

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


GRB_name: GRB150530A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17894
SUBJECT: GRB 150530A: RATIR Optical Observations
DATE:    15/05/31 19:31:54 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC),
William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB),
Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino
Cucchiara (ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), JosÃ© A. de Diego (UNAM), Leonid Georgiev (UNAM),
JesÃºs GonzÃ¡lez (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM), Neil Gehrels (GSFC),
and Harvey Moseley (GSFC) report:

We observed the field of GRB 150530A (Starling et al., GCN 17888) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the
1.5m Harold Johnson Telescope at the Observatorio AstronÃ³mico Nacional on
Sierra San Pedro MÃ¡rtir from 2015/05 31.32 to 2015/05 31.45 UTC (20.08
to 23.21 hours after the BAT trigger), obtaining a total of 2.49 hours
exposure in the r, i, and z bands.

For a source within the Swift-XRT error circle, in comparison with 2MASS, we
obtain the following upper limits (3-sigma):

  r > 24.42
  i > 24.18
  z > 20.44

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.

We thank the staff of the Observatorio AstronÃ³mico Nacional in San Pedro
MÃ¡rtir.


GRB_name: GRB150530B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17895
SUBJECT: GRB 150530B detected in ground analysis of BAT data
DATE:    15/06/02 03:16:46 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <james.r.cummings@nasa.gov>

J. R. Cummings (CPI) and D. M. Palmer (LANL)
report on behalf of the Swift science team:

At 13:28:38 during a preplanned Swift slew, GRB 150530B caused a rate
increase in Swift-BAT.  Photon event data were collected during the slew.
In ground analysis, we detect a significant source in a mosaic image.
The source was at RA, Dec 7.496, +44.290 which is:

RA (J2000)   00h 29m 59.0s
Dec (J2000) +44d 17' 25"

with an estimated 90% containment radius of 3 arcmin.

In BAT, the burst lasted 2.0 +- 0.4 seconds.  The spectrum was soft, with
no detected excess above 100 keV.

The best fit to the spectrum from 15-150 keV is a simple power law with
a photon index of 1.7 +- 0.2.  The fluence in 2 seconds was
(1.25 +- 0.2) x 10^-7 ergs/cm^2.  The uncertainties quoted are estimated
90% confidence.


GRB_name: GRB150530B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17896
SUBJECT: GRB 150530B: Swift ToO observations
DATE:    15/06/02 07:11:16 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift has initiated a ToO observation of the Swift/BAT GRB 150530B. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020522

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the Swift/BAT event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a 
GCN Circular after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

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


GRB_name: GRB150527A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17898
SUBJECT: GRB 150527A: Continued RATIR Observations
DATE:    15/06/02 14:25:00 GMT
FROM:    Nat Butler at Az State U  <natbutler@asu.edu>

Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William
H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB),
J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara
(ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), Jos A. de Diego (UNAM), Leonid Georgiev (UNAM), Jess
Gonzlez (UNAM), Carlos Romn-Ziga (UNAM), Neil Gehrels (GSFC), and
Harvey Moseley (GSFC) report:

We observed the field of GRB 150527A (Evans, et al., GCN 17874) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the
1.5m Harold Johnson Telescope at the Observatorio Astronmico Nacional on
Sierra San Pedro Mrtir initially from 2015/05 27.29 to 2015/05 27.45 UTC
(0.17 to 4.06 hours after the BAT trigger), obtaining a total of 3.10 hours
exposure in the r, i, and z bands and then again from 2015/05 28.25 to
2015/05 28.47 UTC (23.27 to 28.36 hours after the BAT trigger), obtaining a
total of 3.91 hours exposure in the r, i, and z bands.

The source we initially detected (Butler, et al., GCN 17876; RA, Dec =
19:15:50.27, 4:12:4.7; J2000, +/-0.5") in the Swift-XRT error circle
(Evans, et al., GCN 17874) has not faded in our extended dataset and is,
therefore, unlikely to be the afterglow.

We note the REM source (Nicastro, et al., GCN 17881) is marginally detected
in our first epoch observation with i=23.4 +/- 0.5, calibrated relative to
the USNO-B1 catalog.

We thank the staff of the Observatorio Astronmico Nacional in San Pedro
Mrtir.


GRB_name: GRB150530B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17899
SUBJECT: GRB 150530B: Swift-XRT observations
DATE:    15/06/02 14:46:01 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P. D'Avanzo (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows
(PSU), J.A. Kennea (PSU), C. Pagani (U. Leicester), A.P. Beardmore (U.
Leicester), V. D'Elia (ASDC), A. D'a (INAF-IASFPA) and P.A. Evans (U.
Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has performed follow-up observations of the
Swift/BAT-detected burst GRB 150530B (Cummings et al. GCN Circ. 17895),
collecting 4.8 ks of Photon Counting (PC) mode data between T0+239.2 ks
and T0+247.3 ks. 

No X-ray sources have been detected inside or close to the Swift/BAT
error region. The 3-sigma upper limit in the field ranges from ~0.003
to ~0.004 ct s^-1, corresponding to a 0.3-10 keV observed flux of
1.0e-13 to 1.5e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum).

Four uncatalogued sources were detected too far from the GRB position
to be likely afterglow candidates.

The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
http://www.swift.ac.uk/ToO_GRBs/00020522.

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


GRB_name: GRB150530A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17900
SUBJECT: Konus-Wind observation of GRB 150530A
DATE:    15/06/03 17:40:38 GMT
FROM:    Anastasia Tsvetkova at Ioffe Institute  <tsvetkova@mail.ioffe.ru>

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

The long-duration GRB 150530A (Swift-BAT trigger #642018:
Starling  et al., GCN 17888; Markwardt et al., GCN 17890;
Fermi GBM detection: Yu, Younes and Meegan, GCN 17891)
triggered Konus-Wind at T0=42136.529 s UT (11:42:16.529).

The burst light curve shows a single pulse lasting from  ~T0-4 s to ~T0+6 s.
The emission is seen up to ~1.2 MeV.

As observed by Konus-Wind, the burst
had a fluence of 2.54(-0.26,+0.28)x10^-6 erg/cm2,
and a 64-ms peak energy flux, measured from T0+0.082 s,
of 1.06(-0.43,+0.43)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum of the burst
(measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 1.2 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -0.63(-0.38,+0.46),
and Ep = 114(-17,+23) keV (chi2 = 59/58 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index:
beta < -3.07 (chi2 = 59/57 dof).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB150530_T42136/

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


GRB_name: GRB150604A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17902
SUBJECT: Swift trigger 642453 is not an astrophysical source
DATE:    15/06/04 14:58:01 GMT
FROM:    Valerio D'Elia at ASDC  <delia@asdc.asi.it>

V. D'Elia (ASDC), S. D. Barthelmy (GSFC), P. A. Evans (U. Leicester),  
L. Izzo (URoma/ICRA) and M. H. Siegel (PSU) report on behalf of the  
Swift team:


We have analysed 4.5 ks of Swift/XRT data for the Swift/BAT-detected  
possible burst GRB 150604A (D'Elia et al. GCN Circ. 17901), collected  
in Photon Counting mode, between 138 s and 21.6 ks after the BAT  
trigger. No X-ray sources have been detected inside or close to the  
Swift/BAT error region. The 3-sigma upper limit at the Swift/BAT  
position is ~0.002 ct s^-1, corresponding to a 0.3-10 keV observed  
flux of ~1e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum).

Ground analysis of the BAT data for this trigger shows that the  
significance of the initial detection has dropped below that  
considered to be a valid trigger.

Swift/UVOT began settled observation of the field 142 s after the BAT  
trigger. No new source is detected in the initial 1.4 ks of  
observation down to a white magnitude limit of 20.9.

Therefore, this trigger is likely due to noise, and not due to  
anything astrophysical.

This circular is an official product of the Swift team.


GRB_name: GRB150518A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17903
SUBJECT: GRB 150518A: possible SN observations
DATE:    15/06/06 15:19:15 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

A. Pozanenko (IKI), E. Mazaeva (IKI),  A. Sergeev (IRA NASU, IAKhNU), I. 
Reva (Fesenkov Astrophysical Institute), A. Volnova (IKI),  E. Klunko 
(ISTP), I. Korobtsev (ISTP), report on behalf of larger GRB follow-up 
collaboration:

We observed the field of the MAXI/GSC GRB 150518A (Kawamuro, et al., GCN 
17825) with AZT-33IK telescope of Sayan observatory (Mondy), Zeiss-1000 
(East) 1-m telescope of Tien Shan Astronomical
Observatory and AZT-22 telescope of Maidanak observatory.
Observations are continuing in R-filter. The SDSS J153648.25+161946.9 
galaxy which coincides with the optical afterglow (Xu et al., GCN 17829) 
is  detected in all observations. The light curve of the host 
galaxy+afterglow are suggesting re-brightening with a possible maximum 
brightness on June 2-5.  We suggest that this re-brightening can be 
attributed to Supernova associated with GRB 150518A.  Preliminary light 
curve of the possible SN+host can be found in 
http://grb.rssi.ru/GRB150518A/GRB150518A_lc.png

Photometry of the host galaxy+SN at the possible maximum brightness  are 
following

Date       UT start   t-T0     Filter     OT    Err.  Observatory
                       (mid, days)

2015-06-02 17:43:30   14.8605  R          20.89 0.13  TSHAO
2015-06-03 20:33:20   15.8862  R          20.82 0.10  Maidanak
2015-06-05 18:11:19   17.8535  R          20.90 0.07  Maidanak

Photometry is based on SDSS DR9 stars:

SDSS9_id            R(Lupton)
J153646.11+161904.1    17.65
J153638.21+162002.8    18.41
J153637.55+162040.3    17.10
J153645.59+162055.5    16.35

The maximum brightness of a the possible Supernova is an agreement with 
the brightness predicted for the SN at redshift z = 0.256 (Xu et al., 
GCN 17832).


GRB_name: GRB150607A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17904
SUBJECT: GRB 150607A: Swift detection of a burst with an optical counterpart
DATE:    15/06/07 08:10:50 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

V. D'Elia (ASDC), L. Izzo (URoma/ICRA), J. A. Kennea (PSU),
K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU)
report on behalf of the Swift Team:

At 07:55:09 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 150607A (trigger=642620).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 140.024, +68.442 which is 
   RA(J2000) = 09h 20m 06s
   Dec(J2000) = +68d 26' 33"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a multiply-peaked
structure with a duration of about 50 sec.  The peak count rate
was ~3000 counts/sec (15-350 keV), at ~8 sec after the trigger. 

The XRT began observing the field at 07:57:20.5 UT, 130.9 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 139.9916, 68.4368 which is equivalent to:
   RA(J2000)  = +09h 19m 57.98s
   Dec(J2000) = +68d 26' 12.5"
with an uncertainty of 6.5 arcseconds (radius, 90% containment). This
location is 46 arcseconds from the BAT onboard position, within the BAT
error circle. 

The initial flux in the 2.5 s image was 4.64e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 136 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 09:19:57.18 = 139.98825
  DEC(J2000) = +68:26:10.2  =  68.43618
with a 90%-confidence error radius of about 0.75 arc sec. This position is 5.0
arc sec. from the center of the XRT error circle. The estimated magnitude is
18.06 with a 1-sigma error of about  0.15. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.06. 

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: GRB150607A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17905
SUBJECT: GRB 150607A: Enhanced Swift-XRT position
DATE:    15/06/07 12:41:33 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 1781 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 150607A, 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 = 139.98854, +68.43599 which is equivalent
to:

RA (J2000): 09h 19m 57.25s
Dec (J2000): +68d 26' 09.6"

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: GRB150607A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17906
SUBJECT: GRB 150607A: Fermi GBM Detection
DATE:    15/06/07 14:02:19 GMT
FROM:    Oliver Roberts at UCD/Fermi  <oliver.roberts@ucd.ie>

O.J. Roberts (UCD) reports on behalf of the Fermi GBM Team:

"At 07:55:09.85 UT on the 7th of June 2015, the Fermi
Gamma-Ray Burst Monitor triggered and located GRB 150607A
(trigger 455356512 / 150607330), which was also detected
by Swift (D'Elia  et al. 2015, GCN 17904). The GBM
on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight using this position
is about 130 degrees.

The GBM light curve shows several bright pulses over a
duration (T90) of 31.8 s (50-300 keV). The time-averaged
spectrum from T0-1.7 s to T0+30.1 s is well fit by power
law function with an exponential high-energy cutoff. The
power law index is -0.98 +/- 0.17 and the cutoff energy,
parameterized as Epeak, is 137 +/- 22 keV.

The event fluence (10-1000 keV) in this time interval is
(4.4 +/- 0.4)E-06 erg/cm^2. The 1.024-sec peak photon
flux measured starting from T0+6.8 s in the 10-1000 keV
band is 6.8 +/- 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: GRB150607A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17907
SUBJECT: GRB 150607A: Swift-BAT refined analysis
DATE:    15/06/07 22:51:34 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), V. D'Elia (ASDC), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 150607A (trigger #642620)
(D'Elia, et al., GCN Circ. 17904).  The BAT ground-calculated position is
RA, Dec = 140.015, 68.436 deg, which is 
   RA(J2000)  =  09h 20m 03.6s 
   Dec(J2000) = +68d 26' 10.3" 
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 31%.
 
The mask-weighted light curve shows multiple peaks starting at ~T-2 sec,
the brightest peak at ~T+8 sec, and ending at ~T+40 sec.
T90 (15-350 keV) is 26.3 +- 0.7 sec (estimated error including systematics).
 
The time-averaged spectrum from T-0.19 to T+27.58 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 0.99 +- 0.41, 
and Epeak of 84.9 +- 40.1 keV (chi squared 40.9 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 2.3 +- 0.2 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T+7.29 sec in the 15-150 keV band is
4.9 +- 0.5 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.59 +- 0.10 (chi squared 48.1 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/642620/BA/


GRB_name: GRB150607A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17908
SUBJECT: GRB 150607A: NOT optical observations
DATE:    15/06/07 23:42:40 GMT
FROM:    Thomas Kruehler at Dark Cosmology Center  <tom@dark-cosmology.dk>

T. Kruehler (ESO) & A. A. Djupvik (NOT) report on behalf of a larger
collaboration:

We observed the field of GRB 150607A (D'Elia et al., GCN 17904) using
the Nordic Optical Telescope equipped with the ALFOSC camera.

A short series of photometry in BVRI filters was taken starting at
2015-06-07 21:43UT. The optical afterglow (D'Elia et al., GCN 17094) of
GRB 150607A is well detected in our images. We measure R = 21.6 +/- 0.2
mag at 13.76 hours after the trigger, calibrated against magnitudes
of nearby stars from the USNO-B1 catalog.


GRB_name: GRB150607A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17909
SUBJECT: GRB 150607A: Swift/UVOT Detection
DATE:    15/06/08 00:28:17 GMT
FROM:    Lea Hagen at PSU  <lea.zernow.hagen@gmail.com>

L. M. Z. Hagen (PSU) and V. D'Elia (ASDC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150607A
137 s after the BAT trigger (D'Elia et al., GCN Circ. 17904). A source
consistent with the XRT position (Osborne et al. GCN Circ. 17905) is
detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  09:19:57.20 = 139.98833 (deg.)
    Dec (J2000) = +68:26:10.3  =  68.43619 (deg.)
with an estimated uncertainty of 0.44 arc sec. (radius, 90% confidence).

Preliminary detections and 3-sigma upper limits using the UVOT photometric
system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early
exposures are:

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

white              137          286          146         18.10 +/- 0.07
white              628         1204          205         20.04 +/- 0.31
white             1358         7668          412        >20.55
v                  118          128            9         16.71 +/- 0.35
v                  678         7955          446        >19.02
b                  604         7463          367        >19.65
u                  348          598          245         18.88 +/- 0.27
u                  753         7258          352        >19.37
uvw1               728         7053          352        >19.60
uvm2              1084         6848          313        >19.74
uvw2               654         7874          568        >20.30

The magnitudes in the table 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: GRB150607A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17910
SUBJECT: GRB 150607A: Swift-XRT refined Analysis
DATE:    15/06/08 03:10:06 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

D.N. Burrows (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU),
A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), A.
Amaral-Rogers (U. Leicester), A. D'ai (INAF-IASFPA), A. Maselli 
(INAF-IASFPA) and V. D'Elia report on behalf of the Swift-XRT team:

We have analysed 7.7 ks of XRT data for GRB 150607A (D'Elia et al. GCN
Circ. 17904), from 118 s to 47.9 ks after the  BAT trigger. The data
comprise 44 s in Windowed Timing (WT) mode (the first 8 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Osborne et
al. (GCN Circ. 17905).

The light curve can be modelled with an initial power-law decay with an
index of alpha=0.77 (+/-0.06), followed by a break at T+4216 s to an
alpha of 1.11 (+0.26, -0.09).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.82 (+0.11, -0.10). The
best-fitting absorption column is  2.2 (+/-0.4) x 10^21 cm^-2, in
excess of the Galactic value of 5.7 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 4.0 x 10^-11 (5.1 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      2.2 (+/-0.4) x 10^21 cm^-2
Galactic foreground: 5.7 x 10^20 cm^-2
Excess significance: 6.5 sigma
Photon index:      1.82 (+0.11, -0.10)

If the light curve continues to decay with a power-law decay index of
1.11, the count rate at T+24 hours will be 0.020 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.8 x
10^-13 (1.0 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/00642620.

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


GRB_name: GRB150607A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17911
SUBJECT: Konus-Wind observation of GRB 150607A
DATE:    15/06/08 10:59:30 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

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

The long-duration GRB 150607A (Swift-BAT trigger #642620:
D'Elia, et al., GCN 17904; Palmer, et al., GCN 17907;
Fermi GBM detection: Roberts, GCN 17906) triggered Konus-Wind at 
T0=28509.211 s UT (07:55:09.211).

The burst light curve shows a multipeak structure
with a total duration of ~30 s.
The emission is seen up to ~1 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB150607_T28509/

As observed by Konus-Wind, the burst
had a fluence of 4.2(-0.8,+1.3)x10^-6 erg/cm2,
and a 64-ms peak flux, measured from T0-0.222 s,
of 1.2(-0.5,+0.6)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+33.024 s)
is best fit 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 = -1.4(-0.3,+0.4)
and Ep = 173(-57,+183) keV (chi2 = 61/62 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2
(chi2 = 60/61 dof)

The spectrum near the maximum count rate
(measured from T0+0.000 to T0+8.448 s)
is best fit 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 = -1.4(-0.3,+0.4)
and Ep = 152(-42,+108) keV (chi2 = 46/62 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2
(chi2 = 46/61 dof)

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


GRB_name: GRB150608A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17912
SUBJECT: GRB 150608A: MAXI/GSC detection
DATE:    15/06/08 13:22:43 GMT
FROM:    Makoto Arimoto at Tokyo Inst of Tech  <arimoto@hp.phys.titech.ac.jp>

M. Arimoto (Tokyo Tech), H. Negoro (Nihon U.),
S. Ueno, H. Tomida, S. Nakahira, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA),
T. Mihara, M. Sugizaki, M. Serino, M. Shidatsu, J. Sugimoto, T.
Takagi, M. Matsuoka (RIKEN),
N. Kawai, T. Yoshii, Y. Tachibana, Y. Ono, T. Fujiwara (Tokyo Tech),
A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU),
H. Tsunemi, R.Imatani (Osaka U.),
M. Nakajima, K. Tanaka, T. Masumitsu (Nihon U.),
Y. Ueda, T. Kawamuro, T. Hori (Kyoto U.),
Y. Tsuboi, S. Kanetou (Chuo U.),
M. Yamauchi, D. Itoh (Miyazaki U.),
K. Yamaoka (Nagoya U.), M. Morii (ISM)
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray
transient source at 11:46:50 UT.
Assuming that the source flux was constant over the transit,
we obtain the source position at

(R.A., Dec) = (13.389 deg, -0.213 deg) = (00 53 33, -00 12 46) (J2000)

with a statistical 90% C.L. elliptical error region
with long and short radii of 0.50 deg and 0.22 deg, respectively.
The roll angle of long axis from the north direction is 30.0 deg
counterclockwise.
There is an additional systematic uncertainty of 0.1 deg (90%
containment radius).

The X-ray flux averaged over the scan was 294 +- 58 mCrab
(4-10keV, 1 sigma error).

Without assumptions on the source constancy,we obtain a rectangular error
box for the transient source with the following corners:
(R.A., Dec) = (12.424 deg, -0.277 deg) = (00 49 41, -00 16 37) (J2000)
(R.A., Dec) = (12.873 deg, 0.622 deg) = (00 51 29, +00 37 19) (J2000)
(R.A., Dec) = (14.875 deg, -0.382 deg) = (00 59 29, -00 22 56) (J2000)
(R.A., Dec) = (14.462 deg, -1.299 deg) = (00 57 50, -01 17 56) (J2000)
There was no significant excess flux in the previous transit at 6/8 10:14 UT.


GRB_name: GRB150608A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17913
SUBJECT: GRB 150608A: Tiled Swift observations
DATE:    15/06/08 14:00:20 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift has initiated a series of observations, tiled on the sky, of the
MAXI GRB 150608A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00045

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. The probability of finding
serendipitous sources, unrelated to the MAXI event is high: any X-ray source
considered to be a probable afterglow candidate will be reported via a GCN Circular
after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

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


GRB_name: GRB150607A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17914
SUBJECT: GRB150607A: Discovery Channel Telescope Optical Observations
DATE:    15/06/08 17:14:26 GMT
FROM:    Vicki Toy at UMD  <vtoy@astro.umd.edu>

V. Toy (UMD), J. Capone (UMD), S.B. Cenko (NASA-GSFC), S. Veilleux (UMD),
A. Cucchiara (NASA-GSFC), E. Troja (NASA-GSFC),  and A. Kutyrev (NASA-GSFC)
report on behalf of a larger collaboration:

We observed the field of GRB150607A (Swift trigger 642620, D'Elia et al.,
GCN 17904) with the Large Monolithic Imager (LMI) on the 4.3m Discovery
Channel Telescope (DCT) at Happy Jack, AZ from 2015/06/08 03:42 to
2015/06/08 04:35 UTC (starting 19.8 hours after the trigger). A source is
clearly detected at the location of the optical afterglow in r', i', and
z'.  Using nearby point sources from USNO-B1.0 for calibration, we measure
r' = 22.03 +/- 0.03.

This magnitude is reported in AB magnitude and is not corrected for
Galactic extinction in the direction of the GRB.

Compared to NOT observations on 06/07 (Kruehler & Djupvik, GCN 17908) the
afterglow has a decay index of ~ t^-1.1.

We thank the staff of the Discovery Channel Telescope for assistance with
these observations.


GRB_name: GRB150607A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17915
SUBJECT: GRB150607A: AAO and CrAO optical observations
DATE:    15/06/08 17:49:29 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI), R. Inasaridze (AAO), S. Nazarov (CrAO), Sh. 
Makandarashvili (AAO), A. Volnova (IKI), I. Molotov (KIAM), A. Pozanenko 
(IKI) report on behalf of larger GRB follow-up collaboration:

We observed the field of GRB 150607A (Swift trigger 642620, D'Elia et 
al., GCN 17904) with the AS-32 (0.7m) telescope of Abastumani 
Observatory (AAO) starting on June, 07 17:54:22, and with AZT-8 
telescope of CrAO starting on June, 07 19:43:21.  The afterglow of GRB 
150607A (Kruehler et al., GCN 17908; Hagen et al., GCN 17909) is clearly 
detected in early observation in AAO. Preliminary photometry is following.

telescope  UT start   t-T0     Filter   Exp.     OT    Err.
                       (mid, days)       (s)

AS-32      17:54:22   0.45669  None     44*120   21.20 0.1
AZT-8      19:43:21   0.49864  R         6*180  >19.4 (3sigma)

Photometry is based on nearby USNO-B1.0 stars.


GRB_name: GRB150608A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17917
SUBJECT: GRB 150608A: Swift-XRT afterglow detection
DATE:    15/06/08 22:33:22 GMT
FROM:    Maria Grazia Bernardini at INAF/Brera  <grazia.bernardini@brera.inaf.it>

M.G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB), A. Melandri
(INAF-OAB), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), A.
Amaral-Rogers (U. Leicester), J.P. Osborne (U. Leicester), A. D'ai
(INAF-IASFPA), A. Maselli  (INAF-IASFPA), D.N. Burrows (PSU) and P.A.
Evans (U. Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has performed follow-up observations of the MAXI-detected
burst GRB 150608A (Arimoto et al. GCN Circ. 17912) in a series of
observations tiled on the sky. The total exposure time is 3.1 ks,
distributed over 7 tiles; the maximum exposure at a single sky location
was 955 s. The observations started at T0+8.0 ks, and are entirely in
Photon Counting (PC) mode. 

An uncatalogued X-ray source is detected in the data collected between
T0+9.1 ks and T0+14.7 ks. This source is above the RASS limit and is
therefore likely the GRB afterglow. The position of this source is RA,
Dec=13.1663, -0.6442 which is equivalent to:

RA (J2000): 00:52:39.90
Dec(J2000): -00:38:39.0

with an uncertainty of 3.6 arcsec (radius, 90% confidence).  This
position is 29.1 arcmin from the MAXI position.  The light curve is
consistent with a constant source of mean count rate 8.3e-01 ct/sec. 

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.78 (+0.28, -0.26). The
best-fitting absorption column is  9.8 (+8.3, -6.0) x 10^20 cm^-2,
consistent with the Galactic value of 3.8 x 10^20 cm^-2 (Willingale et
al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux
conversion factor deduced from this spectrum  is 3.5 x 10^-11 (4.0 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      9.8 (+8.3, -6.0) x 10^20 cm^-2
Galactic foreground: 3.8 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.78 (+0.28, -0.26)

The results of the XRT-team automatic analysis of the likely afterglow
are at http://www.swift.ac.uk/xrt_products/TILED_GRB00045/index_2.php.
The results of the full analysis of the tiled XRT observations are
available at http://www.swift.ac.uk/xrt_products/TILED_GRB00045.

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


GRB_name: GRB150608A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17918
SUBJECT: Konus-Wind observation of  GRB 150608A
DATE:    15/06/10 11:53:59 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

A long-duration GRB triggered Konus-Wind on June 8, 2015
at T0=42325.791 s UT (11:45:25.791), ~80 s before
the MAXI trigger (GRB 150608A; Arimoto, et al., GCN Circ. 17912).

The KW light curve shows a multi-peaked complex which
started at ~T0-75 s and lasted until ~T0+5 s.
This phase of the emission was followed, in ~75 s,
by a weaker pulse, which triggered MAXI.
Taking into account the proximity of this burst
to the MAXI/GSC trigger and consistency of the
KW ecliptic latitude response with the position
of GRB 150608A we suggest that KW observed
the main part of GRB 150608A.

The K-W light curve of this burst is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB150608_T42325/

As observed by Konus-Wind, the burst had a fluence of 
2.4(-0.3,+0.3)x10^-5 erg/cm2, and a 2.944-s peak flux,
measured from T0-0.302 s, of 8.8(-1.2,+1.2)x10^-7 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

Since the bulk of the burst emission lies before the triggered
mode record, the spectral analysis was performed using
KW 3-channel waiting mode data.

Modeling the 3-channel time-integrated spectrum
(from T0-73.209 s to T0+5.586 s) by a power law
with exponential cutoff (CPL) model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha = -1.56 Â± 0.14, and Ep = 209 Â± 46 keV.

Modelling the 3-channel spectrum near the peak count rate
(from T0-3.246 s to T0+2.642 s) by the CPL model
yields alpha = -0.94 Â± 0.26, and Ep = 199 Â± 37 keV.

All the quoted errors are estimated at the 1 sigma confidence level.
All the presented results are preliminary.


GRB_name: GRB150608A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17920
SUBJECT: GRB 150608A: MITSuME Akeno optical upper limits
DATE:    15/06/12 05:00:24 GMT
FROM:    Taketoshi Yoshii at Tokyo Tech  <yoshii.t.ac@m.titech.ac.jp>

Y.Saito, T.Fujiwara, T. Yoshii, Y. Tachibana, H. Ohuchi, Y. Yano,
S. Kurita, Y.Ono, S.Harita, Y.Muraki, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:

We observed the field of GRB 150608A (M.Arimoto et al., GCN Circular #17912) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan.

The observation started on 2015-06-09 18:17:37 UT (~30.5 h after the burst). We cound not detect any optical point source in the error circle of the previously reported afterglow detected by Swift-XRT (M.G.Bernardini et al., GCN Circular #17917) in all three bands.

Three sigma upper limits are listed below.

T0+[hour]      MID-UT      T-EXP[sec]         g'           Rc           Ic
---------------------------------------------------------------------------------------
  30.5131     18:23:03          600            > 17.9     > 18.0     > 17.4
---------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration


GRB_name: GRB150615A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17923
SUBJECT: GRB 150615A: Swift detection of a burst
DATE:    15/06/15 05:00:00 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

E. Troja (NASA/GSFC/UMCP), S. D. Barthelmy (GSFC),
A. D'Ai (INAF-IASFPA), A. Maselli (INAF-IASFPA), D. M. Palmer (LANL),
T. Sakamoto (AGU), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU)
report on behalf of the Swift Team:

At 04:42:27 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 150615A (trigger=643833).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 107.570, -22.472 which is 
  RA(J2000) = +07h 10m 17s
  Dec(J2000) = -22d 28' 18"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single-peaked
structure with a duration of about 20 sec.  The peak count rate
was ~1000 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 04:44:22.0 UT, 115.0 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source with an enhanced position: RA, Dec
107.5645, -22.4497 which is equivalent to:
   RA(J2000)  = 07h 10m 15.48s
   Dec(J2000) = -22d 26' 58.8"
with an uncertainty of 2.2 arcseconds (radius, 90% containment). This
location is 82 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 4.74
x 10^21 cm^-2 (Willingale et al. 2013). 

The initial flux in the 2.5 s image was 3.94e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 122 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
0.33. 

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: GRB150615A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17924
SUBJECT: GRB 150615A: Enhanced Swift-XRT position
DATE:    15/06/15 08:34:51 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 1338 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 150615A, 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 = 107.56503, -22.44906 which is equivalent
to:

RA (J2000): 07h 10m 15.61s
Dec (J2000): -22d 26' 56.6"

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: GRB150615A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17925
SUBJECT: GRB 150615A: Swift/UVOT Detection
DATE:    15/06/15 13:44:32 GMT
FROM:    Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>

S. R. Oates (IAA-CSIC/UCL-MSSL) and E. Troja (NASA/GSFC/UMCP)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150615A
122 s after the BAT trigger (Troja et al., GCN Circ. 17923).
A faint source consistent with the enhanced XRT position
(Beardmore et al. GCN Circ. 17924) is detected in the
combined white exposures.

Preliminary detection and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: 

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

white              122         1532          392         20.64 +/- 0.19
v                  611         1409           97        >18.3
b                  536         1507           97        >19.9
u                  280         1482          324        >20.2
w1                 660         1458           97        >19.2
m2                 635         1433           97        >18.9
w2                 586         1557          117        >19.4

The magnitudes in the table are not corrected for the significant Galactic
extinction due to the reddening of E(B-V) = 0.33 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB150608A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17926
SUBJECT: GRB 150608A: Swift-XRT follow-up observations
DATE:    15/06/15 13:48:04 GMT
FROM:    Maria Grazia Bernardini at INAF/Brera  <grazia.bernardini@brera.inaf.it>

M.G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB) and A. Melandri 
(INAF-OAB)
report on behalf of the Swift-XRT team:

A second epoch of XRT data was collected on the field of the MAXI-detected
burst: GRB 150608A (Arimoto, et al., GCN Circ. 17912) on 2015 June 13.
The observations consist of 2 ks of PC mode data, from T0+389 ks to 
T0+395 ks.

The X-ray source reported in GCN Circ. 17917, Bernardini et al., 
measured at
a mean count rate of 8.3e-01 count/sec (0.3-10 keV) in the first epoch 
of XRT
observations has faded to a mean count rate of (7.1e-03+/-2.2e-03) 
count/sec
(0.3-10 keV) in the second epoch. Assuming a power-law decay, the 
corresponding
decay index is alpha=1.28 (-0.11, +0.17).  We therefore confirm that 
this is
the X-ray afterglow of GRB 150608A.

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


GRB_name: GRB150615A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17928
SUBJECT: GRB 150615A: Swift-XRT refined Analysis
DATE:    15/06/15 18:01:50 GMT
FROM:    Alessandro Maselli at INAF/IASF Palermo  <maselli@ifc.inaf.it>

A. Maselli (INAF-IASFPA), A. D'Ai (INAF-IASFPA), P.A. Evans (U.
Leicester), B. Sbarufatti (INAF-OAB/PSU), A. Amaral-Rogers (U.
Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.
Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), D.N. Burrows (PSU), J.A.
Kennea (PSU) and E. Troja (NASA/GSFC/UMCP) report on behalf of the
Swift-XRT team:

We have analysed 10 ks of XRT data for GRB 150615A (Troja et al. GCN
Circ. 17923), from 102 s to 30.3 ks after the  BAT trigger. The data
comprise 74 s in Windowed Timing (WT) mode (the first 8 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Beardmore
et al. (GCN Circ. 17924).

The light curve can be modelled with an initial power-law decay with an
index of alpha=3.08 (+0.28, -0.20), followed by a break at T+626 s to
an alpha of 0.17 (+0.08, -0.09).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.48 (+0.25, -0.19). The
best-fitting absorption column is  5.03 (+1.17, -0.29) x 10^21 cm^-2,
consistent with the Galactic value of 4.7 x 10^21 cm^-2 (Willingale et
al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux
conversion factor deduced from this spectrum  is 3.2 x 10^-11 (7.3 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      5.03 (+1.17, -0.29) x 10^21 cm^-2
Galactic foreground: 4.7 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:      2.48 (+0.25, -0.19)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00643833.

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


GRB_name: GRB150615A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17930
SUBJECT: GRB 150615A, Swift-BAT refined analysis
DATE:    15/06/15 21:05:48 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

T. Sakamoto (AGU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
M. Stamatikos (OSU), E. Troja (NASA/GSFC/UMCP), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):

Using the data set from T-640 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 150615A (trigger #643833)
(Troja, et al., GCN Circ. 17923).  The BAT ground-calculated position is
RA, Dec = 107.554, -22.466 deg which is
  RA(J2000)  =  07h 10m 12.8s
  Dec(J2000) = -22d 27' 57.6"
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 85%.

The mask-weighted light curve shows a single pulse that starts at ~ T-3 s,
peaks at ~T+5 s, and ends at ~T+30 s. T90 (15-350 keV) is 27.6 +- 5.1 sec
(estimated error including systematics).

The time-averaged spectrum from T-2.9 to T+30.1 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.84 +- 0.21.  The fluence in the 15-150 keV band is 5.5 +- 0.7 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+5.80 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/643833/BA/


GRB_name: GRB150616A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17936
SUBJECT: GRB 150616A: Swift detection of a burst
DATE:    15/06/16 23:06:21 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

A. Y. Lien (GSFC/UMBC), K. L. Page (U Leicester), D. M. Palmer (LANL)
and M. H. Siegel (PSU) report on behalf of the Swift Team:

At 22:49:19 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 150616A (trigger=644259).  The Swift slewed to the burst
after a delay due to the Earth limb constraint. 
The BAT on-board calculated location is 
RA, Dec 314.705, -53.394 which is 
   RA(J2000) = 20h 58m 49s
   Dec(J2000) = -53d 23' 36"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a complex
structure with a duration of at least 200 sec.  The peak count rate
was ~1500 counts/sec (15-350 keV), at ~3 sec after the trigger. 

The XRT began observing the field at 22:58:50.1 UT, 570.9 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 314.7156, -53.3923 which is equivalent to:
   RA(J2000)  = +20h 58m 51.74s
   Dec(J2000) = -53d 23' 32.3"
with an uncertainty of 4.8 arcseconds (radius, 90% containment). This
location is 23 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 4.54e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 579 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.04. 

Burst Advocate for this burst is A. Y. Lien (amy.y.lien 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: GRB150616A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17937
SUBJECT: GRB 150616A: Enhanced Swift-XRT position
DATE:    15/06/17 07:48:05 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 2598 s of XRT Photon Counting mode data and 6 UVOT
images for GRB 150616A, 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 = 314.71689, -53.39383 which is equivalent
to:

RA (J2000): 20h 58m 52.05s
Dec (J2000): -53d 23' 37.8"

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

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).

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


GRB_name: GRB150616A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17939
SUBJECT: GRB 150616A: Swift-XRT refined Analysis
DATE:    15/06/17 11:06:05 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

K.L. Page (U. Leicester), C. Pagani (U. Leicester), P. D'Avanzo
(INAF-OAB), V. D'Elia (ASDC), A. D'ai (INAF-IASFPA), J.A. Kennea (PSU),
B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), A.P. Beardmore (U.
Leicester) and A.Y. Lien report on behalf of the Swift-XRT team:

We have analysed 10 ks of XRT data for GRB 150616A (Lien et al. GCN
Circ. 17936), from 561 s to 31.6 ks after the  BAT trigger. The data
comprise 979 s in Windowed Timing (WT) mode (the first 8 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Evans et
al. (GCN Circ. 17937).

The late-time light curve (from T0+6.3 ks) can be modelled with an
initial power-law decay with an index of alpha=3.785 (+0.019, -0.768),
followed by a break at T+7888 s to an alpha of 0.94 (+0.14, -0.16).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.75 (+/-0.04). The
best-fitting absorption column is  5.06 (+0.31, -0.30) x 10^21 cm^-2,
in excess of the Galactic value of 3.4 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 2.15 (+0.10, -0.09)
and a best-fitting absorption column of 4.6 (+/-0.5) x 10^21 cm^-2. The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 3.7 x 10^-11 (6.5 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      4.6 (+/-0.5) x 10^21 cm^-2
Galactic foreground: 3.4 x 10^20 cm^-2
Excess significance: 15.3 sigma
Photon index:      2.15 (+0.10, -0.09)

If the light curve continues to decay with a power-law decay index of
0.94, the count rate at T+24 hours will be 0.050 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.9 x
10^-12 (3.3 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/00644259.

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


GRB_name: GRB150616A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17941
SUBJECT: GRB 150616A: Swift-BAT refined analysis
DATE:    15/06/17 16:05:44 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

M. Stamatikos (OSU), S. D. Barthelmy (GSFC),  W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), T. N. Ukwatta (LANL) (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 150616A (trigger #644259)
(Lien, et al., GCN Circ. 17936).  The BAT ground-calculated position is
RA, Dec = 314.713, -53.403 deg which is
  RA(J2000)  =  20h 58m 51.1s
  Dec(J2000) = -53d 24' 11.3"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 28%.

The mask-weighted light curve shows a long multi-peaked structure that starts
at ~ T-50 s and ends at ~ T+710 s. The major pulse starts at ~ T+60 s, peaks
at ~ T+93 s, and ends at ~ T+140 s. There is a weak emission from the source
from T-240 s to T-200 s. There may be additional low-level emission before
this time that we cannot confirm nor rule out. T90 (15-350 keV) is 599.5 +- 99.3 sec
(estimated error including systematics).

The time-averaged spectrum from T-52.3 to T+705.9 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 1.37 +- 0.25,
and Epeak of 92.5 +- 45.9 keV (chi squared 55.79 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 1.9 +- 0.1 x 10^-5 erg/cm2
and the 1-sec peak flux measured from T+93.58 sec in the 15-150 keV band is
2.9 +- 0.4 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.73 +- 0.06 (chi squared 62.56 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/644259/BA/


GRB_name: GRB150616A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17942
SUBJECT: GRB 150616A: Swift/UVOT Upper Limits
DATE:    15/06/17 19:38:08 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@swift.psu.edu>

S. J. LaPorte (PSU) and A. Y. Lien (GSFC/UMBC) report on behalf of the
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150616A
579 s after the BAT trigger (Lien et al., GCN Circ. 17936).
No optical afterglow consistent with the XRT position
(Evans et al. GCN Circ. 17937) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

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

white_FC           579          729          147         >21.0
white              579         7913          616         >21.8
v                  736         2624          214         >19.6
b                  836         2878          365         >20.5
u                  810         2700          214         >20.5
w1                 786         2674          214         >20.2
m2                 760         2649          136         >19.9
w2                1016         2250          156         >20.1

The magnitudes in the table 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: GRB150616A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17947
SUBJECT: GRB 150616A: Watcher optical upper limit
DATE:    15/06/18 16:07:20 GMT
FROM:    Antonio Martin-Carrillo at UCD,Space Science Group  <antonio.martin-carrillo@ucd.ie>

D. Murphy (UCD), A. Martin-Carrillo (UCD), M. Topinka (CTU), L. Hanlon (UCD), H. J. van Heerden (UFS), B. van Soelen (UFS) and P. J. Meintjes (UFS):

We observed the field of GRB 150616A (Lien et al., GCN Circ. #17936) using the 40cm Watcher telescope at Boyden Observatory in South Africa. 

Observations started at 22:52:09 UT, 170 seconds after the burst trigger. A series of 5 sec images were taken in the SDSS r' filter using an Andor CCD camera. 
No credible afterglow is found in any of the individual images at the enhanced XRT location (Evans et al., GCN Circ. #17937). A 3sigma upper limit for a combined 50 second exposure is given below.

Start             | End              | Exposure | Filter | Magnitude
-------------------------------------------------------------------------------------------------
22:52:09 UT | 22:53:15 UT | 10x5 sec |  r'       |  >18.9 (3sigma upper limit)

The upper limit was calculated using nearby stars from the APASS catalogue.

This message can be cited in publications.


GRB_name: GRB150622A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17952
SUBJECT: GRB 150622A: MAXI/GSC detection
DATE:    15/06/22 12:42:11 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

Y. Kawakubo (AGU), S. Nakahira, S. Ueno, H. Tomida, M. Kimura, M. Ishikawa, 
Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Serino, M. Shidatsu, J. Sugimoto, 
T. Takagi, M. Matsuoka (RIKEN), N. Kawai, T. Yoshii, Y. Tachibana (Tokyo Tech), 
A. Yoshida, T. Sakamoto, H. Ohtsuki (AGU), H. Tsunemi, R.Imatani (Osaka U.), 
H. Negoro, M. Nakajima, K. Tanaka, T. Masumitsu (Nihon U.), Y. Ueda, T. Kawamuro, 
T. Hori (Kyoto U.), Y. Tsuboi, S. Kanetou (Chuo U.), M. Yamauchi, D. Itoh (Miyazaki U.), 
K. Yamaoka (Nagoya U.), M. Morii (ISM)

report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient 
source at 10:23:43 UT.  Assuming that the source flux was constant over the transit, 
we obtain the source position at

(R.A., Dec) = (252.028 deg, -52.768 deg) = (16 48 06, -52 46 04) (J2000) 

with a statistical 90% C.L. elliptical error region with long and short radii of 0.22 deg 
and 0.14 deg, respectively.  The roll angle of long axis from the north direction is 62.0 deg 
counterclockwise.  There is an additional systematic uncertainty of 0.1 deg (90% 
containment radius).  The X-ray flux averaged over the scan was 342 +- 40 mCrab
(4-10keV, 1 sigma error).  Without assumptions on the source constancy, we obtain 
a rectangular error box for the transient source with the following corners: 

(R.A., Dec) = (251.874 deg, -52.244 deg) = (16 47 29, -52 14 38) (J2000)
(R.A., Dec) = (251.283 deg, -52.506 deg) = (16 45 07, -52 30 20) (J2000)
(R.A., Dec) = (252.300 deg, -53.392 deg) = (16 49 11, -53 23 29) (J2000)
(R.A., Dec) = (252.900 deg, -53.128 deg) = (16 51 36, -53 07 39) (J2000)

There was no significant excess flux in the previous transit at 8:48 UT.


GRB_name: GRB150622A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17953
SUBJECT: GRB 150622A: Tiled Swift observations
DATE:    15/06/22 14:20:17 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift has initiated a series of observations, tiled on the sky, of the
MAXI GRB 150622A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00046

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. The probability of finding
serendipitous sources, unrelated to the MAXI event is high: any X-ray source
considered to be a probable afterglow candidate will be reported via a GCN Circular
after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

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


GRB_name: GRB150622A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17954
SUBJECT: GRB 150622A: Swift-XRT observations
DATE:    15/06/22 18:22:32 GMT
FROM:    Kim Page at U.of Leicester  <kpa@star.le.ac.uk>

D.N. Burrows (PSU), J.A. Kennea (PSU), V. Mangano (PSU), J.P. Osborne
(U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester), A.
Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC) and P.A.
Evans (U. Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has performed follow-up observations of the MAXI-detected
burst GRB 150622A (Kawakubo et al. GCN Circ. 17952) in a series of
observations tiled on the sky. The total exposure time is 1.9 ks,
distributed over 4 tiles; the maximum exposure at a single sky location
was 1.3 ks. The data were collected between T0+14.2 ks and T0+16.2 ks,
and are entirely in Photon Counting (PC) mode. 

One uncatalogued X-ray source has been detected, it is below the RASS
limit and shows no definitive signs of fading. Therefore, at the
present time we cannot confirm this as the afterglow. Details of this
source are given below:

Source 1:
  RA (J2000):  252.4574  =  16:49:49.79
  Dec (J2000): -52.8499  =  -52:50:59.6
  Error: 5.4 arcsec (radius, 90% conf.)
  Count-rate: 0.032 +/- 0.010 ct s^-1
  Flux: (1.29 +/- 0.41)e-12 erg cm^-2 s^-1 (observed, 0.3-10 keV)

The results of the XRT-team automatic analysis of the tiled XRT
observations, including a position-specific upper limit calculator, are
available at http://www.swift.ac.uk/xrt_products/TILED_GRB00046.

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


GRB_name: GRB150626A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17960
SUBJECT: GRB 150626A: Swift detection of a burst
DATE:    15/06/26 02:26:12 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

T. G. R. Roegiers (PSU), S. D. Barthelmy (GSFC), J. A. Kennea (PSU),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and M. H. Siegel (PSU)
report on behalf of the Swift Team:

At 02:12:49 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 150626A (trigger=646603).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 111.341, -37.764 which is 
   RA(J2000) = 07h 25m 22s
   Dec(J2000) = -37d 45' 50"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a complex
structure with a duration of about 30 sec.  The peak count rate
was ~2000 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 02:14:17.3 UT, 87.8 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 111.33758, -37.78043 which
is equivalent to:
   RA(J2000)  = 07h 25m 21.02s
   Dec(J2000) = -37d 46' 49.5"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 59 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.  We
cannot determine whether the source is fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 3.51
x 10^21 cm^-2 (Willingale et al. 2013). 

The initial flux in the 2.5 s image was 3.03e-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 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. 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 0.36. 

Burst Advocate for this burst is T. G. R. Roegiers (troegiers AT swift.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: GRB150626A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17961
SUBJECT: GRB 150626A: Prompt enhanced Swift-XRT position
DATE:    15/06/26 03:05:00 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Using  promptly downlinked XRT event data for GRB 150626A, we find an
enhanced XRT position of the afterglow: RA, Dec: 111.3364, -37.7804
which is equivalent to:
   RA (J2000)  = 07 25 20.74
   Dec (J2000) = -37 46 49.5
with an uncertainty of 2.0 arcseconds (radius, 90% confidence).
Analysis of the promptly available data is online at
http://www.swift.ac.uk/sper/646603.

Position enhancement is 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: GRB150626A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17962
SUBJECT: GRB 150626A: Enhanced Swift-XRT position
DATE:    15/06/26 05:37:38 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 2166 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 150626A, 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 = 111.33677, -37.78081 which is equivalent
to:

RA (J2000): 07h 25m 20.82s
Dec (J2000): -37d 46' 50.9"

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, MNRAS, 397, 1177).

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


GRB_name: GRB150626A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17964
SUBJECT: GRB 150626A: Swift/UVOT Upper Limits
DATE:    15/06/26 13:57:17 GMT
FROM:    Massimiliano de Pasquale at IASF-Palermo  <m.depasquale@ucl.ac.uk>

M. De Pasquale (UCL-MSSL) and T. Roegiers (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150626A
98 s after the BAT trigger (Roegiers et al., GCN Circ. 17960).
No optical afterglow consistent with the XRT position (Evans
GCN Circ. 17961) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposures and subsequent exposures are:

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

white_FC            98          248          147         >20.4
u_FC               311          561          246         >19.6

white               98         1540          392         >21.1
u                  311         1490          324         >19.8
v                  641         1590           95         >18.8
b                  566         1514           97         >19.7
uw1                690         1465           78         >18.8
um2                665         1440           97         >18.6
uw2                616         1390           97         >19.0

The magnitudes in the table are not corrected for the substantial
Galactic extinction due to the reddening of E(B-V) = 0.37 in the
direction of the burst (Schlegel et al. 1998).


GRB_name: GRB150626A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17965
SUBJECT: GRB 150626A: Swift-XRT refined Analysis
DATE:    15/06/26 14:32:33 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

V. Mangano (PSU), C. Pagani (U. Leicester), A.P. Beardmore (U.
Leicester), P.A. Evans (U. Leicester), V. D'Elia (ASDC), A. D'ai
(INAF-IASFPA), A. Maselli  (INAF-IASFPA), M.C. Stroh (PSU), D.N.
Burrows (PSU) and T.G.R. Roegiers report on behalf of the Swift-XRT
team:

We have analysed 9.2 ks of XRT data for GRB 150626A (Roegiers et al.
GCN Circ. 17960), from 77 s to 31.2 ks after the  BAT trigger. The data
comprise 206 s in Windowed Timing (WT) mode (the first 9 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Evans et
al. (GCN Circ. 17961).

The late-time light curve (from T0+6.3 ks) can be modelled with a
power-law decay with a decay index of alpha=0.65 (+/-0.17).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.08 (+/-0.06). The
best-fitting absorption column is  3.74 (+0.31, -0.24) x 10^21 cm^-2,
consistent with the Galactic value of 3.5 x 10^21 cm^-2 (Willingale et
al. 2013). The PC mode spectrum has a photon index of 2.06 (+0.19,
-0.18) and a best-fitting absorption column of 4.5 (+1.0, -0.9) x 10^21
cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.9 x 10^-11 (6.4 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      4.5 (+1.0, -0.9) x 10^21 cm^-2
Galactic foreground: 3.5 x 10^21 cm^-2
Excess significance: 1.8 sigma
Photon index:      2.06 (+0.19, -0.18)

If the light curve continues to decay with a power-law decay index of
0.65, 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 6.8 x
10^-13 (1.1 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/00646603.

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


GRB_name: GRB150626B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17966
SUBJECT: GRB 150626B: Swift detection of a burst
DATE:    15/06/26 20:36:42 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

L. M. McCauley (PSU), S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC),
H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC) and
B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team:

At 20:22:52 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 150626B (trigger=646786).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 187.672, +66.779, which is 
   RA(J2000)  =  12h 30m 41s
   Dec(J2000) = +66d 46' 45"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a FRED-like structure
with a duration of about 30 sec.  The peak count rate
was ~1500 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 20:24:58.9 UT, 126.1 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source with an enhanced position: RA, Dec 187.6342,
66.7722 which is equivalent to:
   RA(J2000)  = 12h 30m 32.22s
   Dec(J2000) = +66d 46' 19.8"
with an uncertainty of 2.4 arcseconds (radius, 90% containment). This
location is 58 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 (1.69 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 1.1
(+0.98/-0.61) x 10^22 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 131 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
0.01. 

Burst Advocate for this burst is L. M. McCauley (marissamc AT swift.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: GRB150626B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17967
SUBJECT: GRB 150626B: MASTER observations
DATE:    15/06/26 21:27:43 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

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

Rafael Rebolo, Miquel Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias

D.Buckley, S. Potter, A.Kniazev, M.Kotze
South African Astronomical Observatory

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

K.Ivanov, O.Gres, N.M.Budnev, S.Yazev, O.Chuvalaev, V.A.Poleshchuk
Irkutsk State University

V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov, A.Gabovich
Blagoveschensk Educational State University, Blagoveschensk

V.Krushinski, I.Zalozhnih,  A. Popov
Ural Federal University, Kourovka

Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

Claudio Mallamaci, Carlos Lopez and Federico Podest
Observatorio Astronomico Felix Aguilar (OAFA)

MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in Kislovodsk was pointed to the  GRB150626B 216 sec after notice 
time and 260 sec after trigger time at 2015-06-26 20:27:12 UT in two 
polarizations, directly after automatic weather control system give permit 
for observations. On our first (50s exposure)  set we not found  optical 
transient within SWIFT error-box (McCauley et al. GCN 17966) brighter then 
17.5.
The 5-sigma upper limit has been about 17.5 mag


MASTER-IAC  pointed to the  GRB150626B  46   sec after notice time and 90 
sec after trigger time at 2015-06-26 2015-06-26 20:24:22 UT, but the 
images overexposed due to eveninig sky (Sun alt -4 deg.).

The observations is continued.
The message may be cited.


GRB_name: GRB150626B
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17968
SUBJECT: GRB 150626B: Enhanced Swift-XRT position
DATE:    15/06/27 00:32:38 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 591 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 150626B, 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 = 187.63331, +66.77177 which is equivalent
to:

RA (J2000): 12h 30m 31.99s
Dec (J2000): +66d 46' 18.4"

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: GRB150626B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17969
SUBJECT: GRB 150626B: NOT optical upper limits
DATE:    15/06/27 00:42:55 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

D. Xu (NAOC/CAS), J. Telting (NOT), J. P. U. Fynbo (DARK/NBI) report on behalf of a larger collaboration:

We observed the field of GRB 150626B (McCauley et al., GCN 17966) using the 2.56m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. We obtained 2x150s SDSS r-band and 6x180s SDSS z-band frames, with their median time of 1.379 hr and 1.936 hr after the burst, respectively.

No optical source is detected at the (enhanced) XRT position (McCauley et al., GCN 17966; Goad et al., GCN 17968) in our stacked r- and z-band images, down to the limiting magnitudes of r~22.3 mag and z~21.6 mag, respectively.


GRB_name: GRB150626B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17970
SUBJECT: GRB 150626B: Swift/UVOT Upper Limits
DATE:    15/06/27 13:38:34 GMT
FROM:    Massimiliano de Pasquale at IASF-Palermo  <m.depasquale@ucl.ac.uk>

M. De Pasquale (UCL-MSSL) and L. M. McCauley (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150626B
131 s after the BAT trigger (McCauley et al., GCN Circ. 17966).
No optical afterglow consistent with the XRT position (Goad et al.
GCN Circ. 17968) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

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

white_FC           131          281          147         >20.7
u_FC               289          539          246         >20.1
white              131         6476          628         >21.6
v                  620         6887          529         >19.5
b                  545         7647          469         >20.8
u                  289         7502          756         >20.7
w1                 669         7298          529         >20.4
m2                 644         7092          510         >20.3
w2                 595         6682          346         >20.4

The magnitudes in the table 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: GRB150627A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17971
SUBJECT: GRB 150627A: Fermi-LAT detection
DATE:    15/06/27 13:43:14 GMT
FROM:    Makoto Arimoto at Tokyo Inst of Tech  <arimoto@hp.phys.titech.ac.jp>

M. Arimoto (Tokyo Tech), J.E. McEnery (NASA/GSFC), F. Longo (Trieste)
and M. Axelsson (KTH Stockholm) report on behalf of the Fermi-LAT team:


At 04:23:23.68 UT on June 27, 2015, Fermi-LAT detected high-energy emission
from GRB 150627A, which was also detected by Fermi-GBM (trigger
457071806/ 150627183).
The best LAT on-ground location is found to be

 RA, Dec = 117.49, -51.56 (J2000)

 with an error radius of 0.05 deg (90 per cent containment,
statistical error only).
This was 75 deg from the LAT boresight at the time of the trigger and triggered
an autonomous repoint of the spacecraft.

 The data from the Fermi-LAT show a significant increase in the event rate
that is spatially and temporally correlated with the trigger with high
significance.
The highest-energy photon is a 8.1 GeV event which is observed 259 s
after the GBM trigger.

 A Swift ToO has been requested for this burst.

 The Fermi-LAT point of contact for this burst is
Makoto Arimoto (arimoto@hp.phys.titech.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.


GRB_name: GRB150627A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17972
SUBJECT: GRB 150627A: Swift ToO observations
DATE:    15/06/27 13:49:15 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift has initiated a ToO observation of the Fermi/LAT GRB 150627A. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020539

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the Fermi/LAT event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a 
GCN Circular after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

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


GRB_name: GRB150626A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17973
SUBJECT: GRB 150626A: Swift-BAT refined analysis
DATE:    15/06/27 14:12:33 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. G. R. Roegiers (PSU), 
T. Sakamoto (AGU), M. Stamatikos (OSU),
(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 150626A (trigger #646603)
(Roegiers, et al., GCN Circ. 17960).  The BAT ground-calculated position is
RA, Dec = 111.353, -37.803 deg which is 
  RA(J2000)  =  07h 25m 24.8s 
  Dec(J2000) = -37d 48' 10.8" 
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 37%.

The mask-weighted lightcurve shows overlapping peaks starting at
~T-35 sec, peaking at ~T+2 sec, and ending at ~T+140 sec.  T90 (15-350 keV) 
is 144 +- 66 sec (estimated error including systematics).

The time-averaged spectrum from T-47.30 to T+144.70 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.11 +- 0.19.  The fluence in the 15-150 keV band is 1.8 +- 0.2 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T+8.20 sec in the 15-150 keV band
is 0.4 +- 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/646603/BA/


GRB_name: GRB150626B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17974
SUBJECT: GRB 150626B: Swift-XRT refined Analysis
DATE:    15/06/27 15:16:40 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P.A. Evans (U. Leicester), B.P. Gompertz (U. Leicester), A. Maselli 
(INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), B.
Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), T.G.R. Roegiers (PSU),
J.P. Osborne (U. Leicester) and L.M. McCauley report on behalf of the
Swift-XRT team:

We have analysed 8.9 ks of XRT data for GRB 150626B (McCauley et al.
GCN Circ. 17966), from 111 s to 23.5 ks after the  BAT trigger. The
data comprise 8 s in Windowed Timing (WT) mode (taken while Swift was
slewing), with the remainder in Photon Counting (PC) mode. The enhanced
XRT position for this burst was given by Goad et al. (GCN Circ. 17968).
The late-time light curve (from T0+5.3 ks) is consistent with a
constant source of mean count rate 1.9e-01 ct/sec. A power-law fit
gives an index of 0.2 (+0.6, -0.5).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.99 (+/-0.15). The
best-fitting absorption column is  9.6 (+1.4, -1.3) x 10^21 cm^-2, in
excess of the Galactic value of 1.7 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 4.8 x 10^-11 (8.8 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      9.6 (+1.4, -1.3) x 10^21 cm^-2
Galactic foreground: 1.7 x 10^20 cm^-2
Excess significance: 11.7 sigma
Photon index:      1.99 (+/-0.15)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00646786.

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


GRB_name: GRB150627A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17975
SUBJECT: GRB 150627A: Fermi GBM observation
DATE:    15/06/27 16:03:39 GMT
FROM:    Hoi-Fung Yu at MPE  <sptfung@mpe.mpg.de>

H.-F. Yu (MPE), E. Burns, V. Connaughton, A. Goldstein (UAH), and M. Gibby (Jacobs)
report on behalf of the Fermi GBM Team:

"At 04:23:23.68 UT on 27 June 2015, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 150627A (trigger 457071806 / 150627183),
which was also detected by the Fermi LAT (Arimoto et al., GCN 17971).
The GBM on-ground location is consistent with the LAT position.

The GBM trigger resulted in an Autonomous Repoint Request (ARR) 
that was accepted and the spacecraft slewed to the GBM in-flight 
location. At the GBM trigger time, the angle of the LAT localization 
to the LAT boresight is 75 deg.

The GBM light curve consists of multiple pulses
with a duration (T90) of about 65 s (50-300 keV).
The time-averaged spectrum from T0-3.072 s to T0+92.161 s is
best fit by a Band function with Epeak = 233 +/- 5 keV,
alpha = -1.04 +/- 0.01, and beta = -2.18 +/- 0.02.

The event fluence (10-1000 keV) in this time interval is
(1.90 +/- 0.01)E-4 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+59.521 s in the 10-1000 keV band
is 65.2 +/- 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: GRB150627A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17976
SUBJECT: GRB 150627A: Swift-XRT afterglow detection
DATE:    15/06/28 01:43:15 GMT
FROM:    Marissa McCaule at PSU  <marissamc@swift.psu.edu>

B.P. Gompertz (U. Leicester), A. Melandri (INAF-OAB), P. D'Avanzo
(INAF-OAB), V. D'Elia (ASDC), D.N. Burrows (PSU), T.G.R. Roegiers
(PSU), L.M. McCauley (PSU), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester) and P.A. Evans (U. Leicester) report on behalf of the
Swift-XRT team:

Swift-XRT has performed follow-up observations of the
Fermi/LAT-detected burst GRB 150627A (Arimoto et al. GCN Circ. 17971),
collecting 4.9 ks of Photon Counting (PC) mode data between T0+33.6 ks
and T0+51.0 ks. 

An uncatalogued X-ray source is detected inside or close to the
Fermi/LAT error region and is above the RASS limit, and is therefore
likely the GRB afterglow.  The position of this source is RA,
Dec=117.4706, -51.4900 which is equivalent to:

RA (J2000): 07:49:52.94
Dec(J2000): -51:29:23.9

with an uncertainty of 3.5 arcsec (radius, 90% confidence).  This
position is 4.3 arcmin from the Fermi/LAT position. 

The light curve can be modelled with a power-law decay with a decay
index of alpha=2.2 (+/-0.3).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.99 (+/-0.13). The
best-fitting absorption column is  3.5 (+/-0.6) x 10^21 cm^-2, in
excess of the Galactic value of 2.6 x 10^21 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.8 x 10^-11 (5.8 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      3.5 (+/-0.6) x 10^21 cm^-2
Galactic foreground: 2.6 x 10^21 cm^-2
Excess significance: 2.8 sigma
Photon index:      1.99 (+/-0.13)

If the light curve continues to decay with a power-law decay index of
2.2, the count rate at T+24 hours will be 0.066 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.5 x
10^-12 (3.8 x 10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis of the likely afterglow
are at http://www.swift.ac.uk/ToO_GRBs/00020539/index_1.php.
The results of the full analysis of the XRT observations are available
at http://www.swift.ac.uk/ToO_GRBs/00020539.

[GCN OPS NOTE(28jun15):  Per author's request, the copy of the 
Swift-UVOT circular on this burst was deleted.  See GCN 17977 for the 
formal UVOT report on this burst.]


GRB_name: GRB150627A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17977
SUBJECT: GRB 150627A: Swift/UVOT Detection
DATE:    15/06/28 09:26:32 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>

Paul Kuin (MSSL-UCL), Marissa McCauley (PSU) and Daniele Malesani 
(DARK/NBI) report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of the Fermi GRB 
150627A 33622 s after the LAT trigger (Arimoto et al., GCN Circ. 17971; 
Yu et al., GCN Circ. 17975).

An optical object consistent with the XRT position (Gompertz et al., GCN 
Circ. 17976) is detected at RA, Dec = 117.47108, -51.489417 deg (J2000), 
which is equivalent to:

RA (J2000):  07:49:53.06
Dec(J2000): -51:29:21.9

with an uncertainty of 1".

Preliminary detections using the UVOT photometric system (Breeveld et 
al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures are:

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

white         33963          34289         335     19.11+/-0.10
white         39860          40112         248     19.55+/-0.17
white         45659          45863         204     19.28+/-0.14
v         34304          34601         298     19.02+/-0.32
v         40117          40346         225     18.98+/-0.36
u         33622          38243         577     18.90+/-0.10
u         43668          45654         966     19.00+/-0.11

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening of E(B-V) = 0.32 in the direction of the 
burst (Schlegel et al. 1998).

While no optical variability can be securely inferred from the UVOT 
photometry, the source is not visible in the DSS survey, and brighter 
than its limit, which suggests it to be the optical afterglow of GRB 
150627A.


GRB_name: GRB150627A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17978
SUBJECT: GRB 150627A: MASTER-SAAO OT Detection
DATE:    15/06/28 09:35:42 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

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


D.Buckley, S. Potter, A.Kniazev, M.Kotze
South African Astronomical Observatory


Rafael Rebolo, Miquel Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias


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

K.Ivanov, O.Gres, N.M.Budnev, S.Yazev, O.Chuvalaev, V.A.Poleshchuk
Irkutsk State University

V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov, A.Gabovich
Blagoveschensk Educational State University, Blagoveschensk

V.Krushinski, I.Zalozhnih
Ural Federal University, Kourovka

Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

Claudio Mallamaci, Carlos Lopez and Federico Podest
Observatorio Astronomico Felix Aguilar (OAFA)

MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in SAAO was pointed to the  GRB150627.18 10133 sec after notice 
time and 55479 sec after trigger time at 2015-06-27 19:48:02 
16:32:07 UT. On our 
first (180s exposure)  set we  found optical transient within LAT 
error-box (ra=07 49 57 dec=-51 33 34 r=0.500000, Arimoto et al., GCN 
17791) brighter then 16.87.

07h 49m 53.05s , -51d 29m 21s.4  error =+-1.0
m ~ 19.0

This postion 2 arcsec close X-ray position (Gompertz et al., 17976)
The 5-sigma upper limit has been about 16.87mag
The message may be cited.


GRB_name: GRB150627A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17979
SUBJECT: GRB 150627A: corection to 17978
DATE:    15/06/28 10:01:04 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

  V. Lipunov (Lomonosov MSU)

I am sorry for mistake.
The correct time of the first exposition is 2015-06-27 16:32:07 (43664 s 
after trigger).
I am out from good internet now. So, I did no see UVOT OT detection
Paul Kuin et al.,GCN 17977 .

The message may be cited.


GRB_name: GRB150626B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17981
SUBJECT: GRB 150626B, Swift-BAT refined analysis
DATE:    15/06/28 20:03:41 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

S. D. Barthelmy (GSFC),  J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
L. M. McCauley (PSU), D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):

Using the data set from T-240 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 150626B (trigger #646786)
(McCauley et al., GCN Circ. 17966).  The BAT ground-calculated position is
RA, Dec = 187.627, 66.794 deg which is
  RA(J2000)  =  12h 30m 30.6s
  Dec(J2000) = +66d 47' 39.6"
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 35%.

The mask-weighted light curve shows a single-peaked structure that starts
at ~T-15 s, peaks at ~T+1 s, and ends at ~T+30 s. T90 (15-350 keV)
is 48.0 +- 22.6 sec (estimated error including systematics).

The time-averaged spectrum from T-15.6 to T+32.4 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.36 +- 0.21.  The fluence in the 15-150 keV band is 1.0 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+7.94 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/646786/BA/


GRB_name: GRB150627A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17982
SUBJECT: Konus-Wind observation of GRB 150627A
DATE:    15/06/29 14:29:44 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

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

The long-duration, bright GRB 150627A
(Fermi-LAT detection: Arimoto, et al., GCN Circ. 17971;
Fermi-GBM detection: Yu, GCN Circ. 17975)
triggered Konus-Wind at T0=15806.292 s UT (04:23:26.292).

The burst light curve shows a bright multi-peaked structure
from ~T0-6 s to ~T0+80 s followed by a weak tail,
which is traceable out to ~T0 + 150 s.
The emission is seen up to ~15 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB150627_T15806/

As observed by Konus-Wind, the burst
had a fluence of 2.34(-0.11,+0.12)x10^-4 erg/cm2,
and a 64-ms peak flux, measured from T0+12.240 s,
of 2.02(-0.27,+0.27)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+81.408 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.98(-0.04,+0.05),
the high energy photon index beta = -2.25(-0.08,+0.07),
the peak energy 217(-13,+14) keV
(chi2 = 125/96 dof)

The spectrum near the maximum count rate
(measured from T0+9.728 to T0+12.800 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.55(-0.07,+0.08),
the high energy photon index beta = -2.52(-0.29,+0.18),
the peak energy 412(-38,+40) keV
(chi2 = 114/94 dof)

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


GRB_name: GRB150622A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17987
SUBJECT: GRB 150622A: Swift-XRT afterglow detection
DATE:    15/07/02 07:40:41 GMT
FROM:    Kim Page at U.of Leicester  <kpa@star.le.ac.uk>

D.N. Burrows (PSU), J.A. Kennea (PSU), V. Mangano (PSU), J.P. Osborne
(U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester), A.
Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC) and P.A.
Evans (U. Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has conducted further observations of the field of the
MAXI-detected burst GRB 150622A (Kawakubo et al. GCN Circ. 17952). The
observations now extend from T0+14.7 ks to T0+843.1 ks. The source
previously reported by Burrows et al. (GCN Circ. 17954), "Source 1", is
fading with 3-sigma significance, and is therefore likely the GRB
afterglow. Using 483 s of PC mode data and 1 UVOT image, we find an
enhanced XRT position (using the XRT-UVOT alignment and matching UVOT
field sources to the USNO-B1 catalogue): RA, Dec = 252.45633, -52.85017
which is equivalent to:

RA (J2000): 16h 49m 49.52s
Dec(J2000): -52d 51' 00.6"

with an uncertainty of 4.1 arcsec (radius, 90% confidence). This
position is 16.3 arcmin from the MAXI position.  The source is fading
with alpha >0.4.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020534.
The results of the full analysis of the tiled XRT observations are
available at http://www.swift.ac.uk/xrt_products/TILED_GRB00046.

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


GRB_name: GRB150702A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17989
SUBJECT: GRB 150702A: Fermi-LAT detection
DATE:    15/07/04 22:56:29 GMT
FROM:    Giacomo Vianello at SLAC  <giacomov@slac.stanford.edu>

G.Vianello (Stanford University),  M.E. Monzani (SLAC), M. Axelsson
(Stockholm University)

report on behalf of the Fermi-LAT team:

On July, 02, 2015 Fermi-LAT detected high-energy emission from GRB
150702A, which triggered Fermi-GBM at 23:56:38.55 UT (trigger
457574201 / 150702998).

The LAT data from this burst were made available to the Fermi
collaboration and to the public with an unusually long delay, due to
an issue with ground software which affected the event reconstruction
pipeline. This issue has now been solved.

The best LAT on-ground location is found to be

RA, Dec = 52.78, -57.00 (J2000)

with an error radius of 0.36 deg (90 % containment, statistical error only).

The GRB was outside the field of view of the LAT at the trigger time,
but entered the FOV ~500 s after the trigger and exited again ~3000 s
after the trigger.

The data from the Fermi-LAT show a significant increase in the event
rate that is spatially and temporally correlated with the trigger with
high significance.

The highest-energy photon is a 800 MeV event which is observed ~1200
seconds after the GBM trigger.

A Swift ToO has been requested for this burst.

The Fermi-LAT point of contact for this burst is Magnus Axelsson
(magnusa@astro.su.se).

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


GRB_name: GRB150702A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17990
SUBJECT: GRB 150702A: Swift ToO observations
DATE:    15/07/05 04:00:28 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift has initiated a ToO observation of the Fermi/LAT GRB 150702A. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020541

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the Fermi/LAT event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a 
GCN Circular after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

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


GRB_name: GRB150702A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17991
SUBJECT: GRB 150702A: Swift-XRT observations
DATE:    15/07/05 11:52:48 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. D'ai (INAF-IASFPA), T.G.R.
Roegiers (PSU), L.M. McCauley (PSU), J.A. Kennea (PSU), J.P. Osborne
(U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester) and
P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has performed follow-up observations of the
Fermi/LAT-detected burst GRB 150702A (Vianello et al. GCN Circ. 17989),
collecting 4.5 ks of Photon Counting (PC) mode data between T0+167.6 ks
and T0+180.0 ks. 

Two uncatalogued X-ray sources have been detected, however none of them
is above the RASS limit or shows definitive signs of fading. Therefore,
at the present time we cannot identify which, if any, is the afterglow.
Details of these sources are given below:

Source 1:
  RA (J2000):  53.1085  =  03:32:26.05
  Dec (J2000): -57.0628  =  -57:03:46.1
  Error: 9.8 arcsec (radius, 90% conf.)
  Count-rate: (3.6 +/- 1.7)e-3 ct s^-1
  Flux: (1.42 +/- 0.67)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 2:
  RA (J2000):  52.7486  =  03:30:59.65
  Dec (J2000): -56.9320  =  -56:55:55.1
  Error: 7.7 arcsec (radius, 90% conf.)
  Count-rate: (1.57 [+0.85, -0.66])e-3 ct s^-1
  Flux: (6.3 [+3.4, -2.6])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)

The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
http://www.swift.ac.uk/ToO_GRBs/00020541.

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


GRB_name: GRB150702A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17992
SUBJECT: GRB 150702A: MASTER-SAAO inspection
DATE:    15/07/05 14:53:44 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

D.Buckley, S. Potter, A.Kniazev, M.Kotze
South African Astronomical Observatory

E. Gorbovskoy,  V. Lipunov,  N.Tyurina, V.Kornilov, 
P.Balanutsa, A.Kuznetsov, E.Popova, D.Kuvshinov,
Lomonosov Moscow State University, Sternberg Astronomical Institute

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias

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

K.Ivanov, O.Gres, N.M.Budnev, S.Yazev, O.Chuvalaev, V.A.Poleshchuk
Irkutsk State University

V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov, A.Gabovich
Blagoveschensk Educational State University, Blagoveschensk

V.Krushinski, I.Zalozhnih
Ural Federal University, Kourovka

Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

Carlos Lopez, Claudio Mallamaci and Federico Podest
Observatorio Astronomico Felix Aguilar (OAFA)

MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in SAAO automaticaly was starting survey on the FERMI  GRB150702A 
error-box (ra=03 34 31 dec=-57 43 12 r=1.110000)  4575 sec after notice time and 
4708 sec after trigger time at 2015-07-03 01:15:06 UT. The 5-sigma upper 
limit on our first (60s exposure)  set is about 18.0 mag
Any uncatalogued optical sources inside Fermi-LAT error box (Evans et 
al., GCN 17990)  detected in this 
observations. No OT detected at XRT Source 1 and 2 positions (D'Avanzo 
et al., GCN 17991).

The full covering map is available at 
httP://observ.pereplet.ru/images/GRB150702A_map.jpg  .

The message may be cited.


GRB_name: GRB150702A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17993
SUBJECT: IPN Triangulation of GRB 150702A
DATE:    15/07/05 16:18:24 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val@mail.ioffe.ru>

K. Hurley, on behalf of the IPN,

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

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

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

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C.
Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer, on
behalf of the Swift-BAT team, and

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

GRB 150702A, localized by Fermi-LAT (Vianello, Monzani, & Axelsson GCN 
Circ. 17989), has been also observed by Fermi (GBM trigger 457574201), 
Konus-Wind, INTEGRAL (SPI-ACS), Swift (BAT), and Mars Odyssey (HEND), so 
far, at about 86198 s UT (23:56:38). The burst was outside the coded 
field of view of the BAT.

We have triangulated this GRB to a Konus-MarsOdyssey annulus centered at
RA(2000)=95.937 deg (06h 23m 45s)  Dec(2000)=+24.107 deg (+24d 06' 24"), 
whose radius is 88.902 Â± 0.055 deg (3 sigma).

This annulus intersects the Fermi-LAT 90% CL error circle (Vianello, 
Monzani, & Axelsson, GCN Circ. 17989) to form an error box whose area is 
about 5 times smaller than that of the LAT error circle, and whose
corners are:
-----------------------------------------------
    RA(2000), deg                 Dec(2000), deg
-----------------------------------------------
1 53.1503 (03h 32m 36s) -57.2987 (-57d 17' 55")
2 53.2998 (03h 33m 12s) -57.2234 (-57d 13' 24")
3 52.2673 (03h 29m 04s) -56.7738 (-56d 46' 26")
4 52.1653 (03h 28m 40s) -56.8692 (-56d 52' 09")
-----------------------------------------------

Both XRT sources (D'Avanzo et al., GCN Circ. 17991) are outside the IPN 
annulus and, hence, unlikely related to the GRB.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB150702_T86198/IPN/


GRB_name: GRB150702A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17994
SUBJECT: GRB 150702A: Fermi GBM detection
DATE:    15/07/06 16:26:42 GMT
FROM:    Peter Jenke at MSFC  <peter.a.jenke@nasa.gov>

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

"At 23:56:38.54 on July 2 2015, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 150702A (trigger 457574202/150702998) which
was also detected by Fermi-LAT (G.Vianello et al. 2015, GCN 17989). 
The GBM on-ground location, using the Fermi GBM trigger
data, is consistent with the LAT location and the IPN triangulation 
(K. Hurley et al. 2015, GCN 17993). 

The initial angle of the burst direction to the Fermi LAT boresight was 
119 degrees.

The GBM light curve consists of multiple peaks with a duration
(T90) of about 45 s (50-300 keV).
The time-averaged spectrum from T0+0s to T0+26s 
is well fit by a Band function with Epeak = 987 +/- 100 keV, 
Alpha = -0.91 +/- 0.04 and Beta = -2.4 +/- 0.2. 
The event fluence (10-1000 keV) in this time interval is
(2.1 +/- 0.4)E-05 erg/cm^2. The 1.0-sec peak photon flux measured
starting from T0+1.3 s in the 10-1000 keV band
is 10.4 +/- 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: GRB150702A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17995
SUBJECT: Konus-Wind observation of GRB 150702A
DATE:    15/07/06 16:56:21 GMT
FROM:    Anastasia Tsvetkova at Ioffe Institute  <tsvetkova@mail.ioffe.ru>

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

The long-duration, hard-spectrum GRB 150702A
(Fermi-LAT detection: Vianello, Monzani & Axelsson, GCN 17989;
IPN triangulation: Hurley et al., GCN 17993;
Fermi GBM detection: Jenke, GCN 17994)
triggered Konus-Wind at T0=86198.645 s UT (23:56:38.645).

The burst light curve starts, at ~T0-0.5 s, with a double-peaked pulse
which is followed by the weaker flaring which extends till ~T0+70 s.
The emission is seen up to ~18 MeV.

As observed by Konus-Wind, the burst
had a fluence of 5.50(-1.45,+1.86)x10^-5 erg/cm2,
and a 64-ms peak energy flux, measured from T0+1.200 s,
of 1.75(-0.61,+0.70)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum of the burst
(measured from T0 to T0+65.984 s)
is best fit in the 20 keV - 18 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -1.24(-0.09,+0.11),
and Ep = 2059(-903,+1940) keV (chi2 = 106/98 dof).

The spectrum near the peak count rate
(measured from T0 to T0+8.640 s)
is best fit in the 20 keV - 18 MeV range
by the power law with exponential cutoff model:
with  alpha = -1.11(-0.11,+0.14),
and Ep = 2310(-1007,+2032) keV (chi2 = 103/97 dof).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB150702_T86198/

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


GRB_name: GRB150626B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  17997
SUBJECT: GRB 150626B: AMI 16 GHz detection of the radio counterpart
DATE:    15/07/07 14:12:27 GMT
FROM:    Kunal Mooley at Oxford U  <kunal.mooley@physics.ox.ac.uk>

K. P. Mooley, G. E. Anderson, R. P. Fender, T. D. Staley (University of 
Oxford),
A. J. van der Horst (George Washington University), A. Rowlinson (CASS)

We observed the position of GRB 150626B (McCauley et al., GCN 17966,
Goad et al., GCN 17968) at 16 GHz with the Arcminute Microkelvin Imager
(AMI-LA) at 2015 June 26.85, June 27.58, and July 03.56 UT, corresponding
to 0.01 days, 0.73 days and 6.71 days post-burst respectively. The GRB
flux densities at these three epochs were <0.19 mJy (3 sigma upper limit),
0.17+/-0.05 mJy (marginal detection), and 0.29+/-0.06 mJy (confirmed 
detection)
respectively.

Further AMI monitoring is ongoing. We thank the AMI scheduling team for
carrying out these observations.


GRB_name: GRB150710A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18001
SUBJECT: GRB 150710A: RATIR Observations
DATE:    15/07/10 04:58:33 GMT
FROM:    Nat Butler at Az State U  <natbutler@asu.edu>

Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William
H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB),
J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara
(ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), JosÃ© A. de Diego (UNAM), Leonid Georgiev (UNAM), JesÃºs
GonzÃ¡lez (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM), Neil Gehrels (GSFC), and
Harvey Moseley (GSFC) report:

We observed the field of possible GRB 150710A (trigger 648437; Bernardini,
et al., GCN 18000) with the Reionization and Transients Infrared Camera
(RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the
Observatorio AstronÃ³mico Nacional on Sierra San Pedro MÃ¡rtir from 2015/07
10.16 to 2015/07 10.20 UTC (3.47 to 4.31 hours after the BAT trigger),
obtaining a total of 0.71 hours exposure in the r, i, and z bands.

For a source within the Swift-XRT error circle, in comparison with the SDSS
DR9 catalog, we obtain the following upper limits (3-sigma):

  r > 23.4
  i > 23.2
  z > 19.4

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the possible GRB.

We thank the staff of the Observatorio AstronÃ³mico Nacional in San Pedro
MÃ¡rtir.  Further observations are ongoing.


GRB_name: GRB150710A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18002
SUBJECT: GRB 150710A: Swift-BAT refined analysis
DATE:    15/07/10 13:52:31 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

S. D. Barthelmy (GSFC), M. G. Bernardini (INAF-OAB), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(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 150710A (trigger #648437)
(Bernardini, et al., GCN Circ. 18000).  The BAT ground-calculated position is
RA, Dec = 194.484, 14.309 deg, which is 
   RA(J2000)  =  12h 57m 56.3s 
   Dec(J2000) = +14d 18' 32.3" 
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.
 
The mask-weighted light curve shows two, possibly 4, overlapping peaks.
T90 (15-350 keV) is 0.15 +- 0.06 sec (estimated error including systematics).
 
The time-averaged spectrum from T+0.02 to T+0.22 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
0.63 +- 0.20.  The fluence in the 15-150 keV band is 7.1 +- 0.9 x 10^-8 erg/cm2.
The 1-sec peak photon flux measured from T-0.38 sec in the 15-150 keV band
is 0.7 +- 0.1 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 

These results are entirely consistant with a short GRB.
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/648437/BA/


GRB_name: GRB150710A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18003
SUBJECT: Konus-Wind observation of GRB 150710A (Swift trigger 648437)
DATE:    15/07/10 13:58:12 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

The short-duration GRB 150710A (Swift trigger 648437:
Bernardini, et al., GCN Circ. 18000) triggered Konus-Wind
at T0=1681.682 s UT (00:28:01.682).

The burst light curve shows a short, double-peaked pulse with
a total duration of ~0.1 s.

As observed by Konus-Wind, the burst had a fluence of
(3.7 Â± 0.7)x10^-7 erg/cm2, and a 16-ms peak flux,
measured from T0-0.048 s, of (7.6 Â± 1.5)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

Since the bulk of the burst emission was detected before
the trigger, the spectral analysis was performed using
the KW 3-channel light curve data.

Modeling the 3-channel time-integrated spectrum
(from T0-0.048 s to T0+0.048 s) by a power law
with exponential cutoff (CPL) model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha = -0.28 Â± 0.54, and Ep = 308 Â± 70 keV.

The K-W light curve of this burst is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB150710_T01681/

Following Bernardini, et al. (GCN Circ. 18000),
we note, that the burst, as observed by Konus-Wind,
is comparable in hardness and other aspects to a typical
short GRB from the KW sample.
The figure showing the GRB 150710A position in the hardness-duration
diagram (logT50-logHR32) of 1143 KW bright GRBs is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB150710_T01681/HR32vsT50.png
The contours denote the 1, 2, and 3 sigma confidence regions for
two-dimensional Gaussian distributions. The vertical dashed line at
T50=0.6 s marks the boundary between short and long KW GRBs.

All the quoted errors are estimated at the 1 sigma confidence level.
All the presented results are preliminary.


GRB_name: GRB150710A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18005
SUBJECT: Swift-XRT observations of GRB 150710A
DATE:    15/07/10 18:09:11 GMT
FROM:    Maria Grazia Bernardini at INAF/Brera  <grazia.bernardini@brera.inaf.it>

M.G. Bernardini, P. D'Avanzo, A. Melandri, S. Campana,
G. Tagliaferri (INAF-OAB), D. Burrows (PSU), K. Page
and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:

We analyzed the full dataset of Swift-XRT observations of the
Swift trigger 648437 (Bernardini et al., GCN Circ. 18000),
classified as short GRB 150710A (Barthelmy et al., GCN Circ.
18002, Golenetskii et al. GCN Circ. 18003), comprising 11.2 ks in
Photon Counting (PC) mode. One X-ray source has been detected
within the BAT error circle at the following position:

  RA (J2000):  194.47045  = 12:57:52.91
  Dec (J2000): 14.31807 = +14:19:05.0
  Error: 2.8 arcsec (radius, 90% conf.)

This position is consistent with the location of a ROSAT faint source
1RXS J125754.7+14185. In an initial 0.98 ks observation carried out
between T+57s and T+1056s, the source has an initial count-rate of
(3.22E-02 Â± 6.3E-03) ct/s. Then in a subsequent 10 ks observation,
carried out between T+4.9 ks and T+34.5 ks, it is no longer detected
down to a 3sigma UL of 1.3E-3 ct/s. The source is near the edge of
the Virgo cluster, but the non-detection of any host galaxy by RATIR
(Butler et al., GCN Circ. 18001) argues against the possibility of this
being a giant SGR flare from a galaxy in the Virgo cluster. Given the
observed fading, we propose this source as the X-ray counterpart of
GRB 150710A.

We also note the possible presence of a second source at the following 
position:

  RA (J2000):  194.4810088073  =  12:57:55.44
  Dec (J2000): 14.317574983  =  +14:19:03.3
  Error: 6.0 arcsec (radius, 90% conf.)

also consistent with the location of 1RXS J125754.7+14185. The source
is detected at a low significance, and it is not possible with present data
to assess if is real or not. Further observation can confirm if this second
source is real and if it is possibly related to 1RXS J125754.7+14185.
Otherwise, we cannot exclude that the observed X-ray emission from
Source #1 is due to a brightening from 1RXS J125754.7+14185.

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


GRB_name: GRB150710A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18006
SUBJECT: GRB 150710A: host galaxy for Swift XRT second candidate
DATE:    15/07/10 19:18:38 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

  V. Lipunov (Lomonosov Moscow State University)

There is SDSS9 galaxy at second XRT candidate  postion (Bernardini et al., 
GCN 18005) J125755.36+141905.7 .
Rmag = 22.1, gmag = 24
That is correspond to z ~ 1 for big galaxy like to Milky Way.
The follow up observation for redshift is needed.

The message may be cited.


GRB_name: GRB150710A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18008
SUBJECT: GRB 150710A: Swift/UVOT Upper Limits
DATE:    15/07/10 20:15:24 GMT
FROM:    Massimiliano de Pasquale at IASF-Palermo  <m.depasquale@ucl.ac.uk>

M. De Pasquale (UCL-MSSL) and M.G. Bernardini (INAF/OAB)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150710A
54 s after the BAT trigger (Bernardini et al., GCN Circ. 18000).
No optical afterglow consistent with the position of the XRT sources
(Bernardini et al., GCN Circ 18005) is detected in the initial UVOT 
exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

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

white_FC            54          204          147         >20.6
u_FC               266          516          246         >19.9

white               54         1017          334         >21.1
v                  595         1050           41         >18.1
b                  521          714           39         >19.1
u                  266          516          285         >20.0
uw1                645          837           39         >18.5
um2                620          812           39 >18.2
uw2                571         1043           58         >19.0

The magnitudes in the table are 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: GRB150710B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18009
SUBJECT: GRB 150710B detected in ground analysis of BAT data
DATE:    15/07/11 14:23:08 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <james.r.cummings@nasa.gov>

J. R. Cummings (CPI), D. M. Palmer (LANL), V. Pal'shin(Ioffe),
and D. Svinkin (Ioffe)

At 08:05:35, the bright GRB 150710B was observed by Swift/BAT during a
preplanned Swiftslew.  It was also seen by KONUS/WIND, and the KW team
notified the BAT team of the event.  In a mosaic of BAT images from photon-
eventdata recorded during the slew, a bright source was found at
RA, Dec 83.195, -46.963,which is:

RA (J2000)05h 32m 46.9s
Dec (J2000) -46d 57' 47"

with an estimated uncertainty of 2 arcmin 90% containment.

The burst had an estimated T90 of about 16 seconds.  There were multiple
bright peaks and an exponential decay.

A Swift TOO has been requested in order to locate the afterglow.


GRB_name: GRB150710B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18010
SUBJECT: GRB 150710B: Swift ToO observations
DATE:    15/07/11 16:11:15 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift has initiated a ToO observation of the Swift/BAT GRB 150710B. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020542

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the Swift/BAT event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a 
GCN Circular after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

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


GRB_name: GRB150711A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18011
SUBJECT: GRB 150711A: Swift detection of a burst
DATE:    15/07/11 18:39:14 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

M. G. Bernardini (INAF-OAB), S. D. Barthelmy (GSFC),
D. N. Burrows (PSU), F. E. Marshall (NASA/GSFC),
A. Melandri (INAF-OAB), D. M. Palmer (LANL) and
B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team:

At 18:23:03 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 150711A (trigger=648601).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 221.631, -35.471 which is 
   RA(J2000)  =  14h 46m 31s
   Dec(J2000) = -35d 28' 15"
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 ~2200 counts/sec (15-350 keV), at ~2 sec after the trigger. 

The XRT began observing the field at 18:24:50.4 UT, 106.7 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source with an enhanced position: RA, Dec
221.6268, -35.4565 which is equivalent to:
   RA(J2000)  = 14h 46m 30.44s
   Dec(J2000) = -35d 27' 23.4"
with an uncertainty of 2.3 arcseconds (radius, 90% containment). This
location is 53 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 8.25
x 10^20 cm^-2 (Willingale et al. 2013). 

The initial flux in the 2.5 s image was 1.13e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 117 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
0.09. 

Burst Advocate for this burst is M. G. Bernardini (grazia.bernardini 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.)


GRB_name: GRB150711A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18012
SUBJECT: GRB 150711A: Enhanced Swift-XRT position
DATE:    15/07/11 21:17:31 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 676 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 150711A, 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 = 221.62678, -35.45603 which is equivalent
to:

RA (J2000): 14h 46m 30.43s
Dec (J2000): -35d 27' 21.7"

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

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).

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


GRB_name: GRB150710B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18013
SUBJECT: GRB 150710B refined analysis
DATE:    15/07/11 23:18:10 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <james.r.cummings@nasa.gov>

J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
  
Using the data set from T-47 to T+50 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 150710B.  (Cummings, et al., GCN Circ.
18009).  The refined BAT position is RA, Dec = 83.191, -46.960 deg, which is
    RA(J2000)  =  05h 32m 45.8s
    Dec(J2000) = -46d 57' 34"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.
  
The mask-weighted light curve shows 6 overlapping but well-defined peaks
followed by an exponential decay to background.  T90 (15-350 keV) is
15 +- 1 sec (estimated error including systematics).
  
The time-averaged spectrum from T+0 to T+15 sec is best fit by a model of a
power law with an exponential cutoff.  The photon index of the time-averaged
spectrum is 0.99 +- 0.09.  Epeak was 166 +- 28 keV.  Using this model, the
fluence in the 15-150 keV band was (3.5 +- 0.1) x 10^-6 ergs/cm^2.  A simple
power-law fit has a photon index of 1.34 +- 0.02.

The 1-sec peak photon flux measured from T+3.5 sec in the 15-150 keV band
was 8.3 +- 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

A Swift TOO is being executed (Evans, GCN #18010).

Because this was a ground-detected burst, the usual automated BAT data
products are not available.


GRB_name: GRB150711A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18014
SUBJECT: GRB 150711A: Observations from the 2.5m NOT
DATE:    15/07/11 23:51:28 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte@iaa.es>

Antonio de Ugarte Postigo (DARK/NBI), and Vincent Van Eylen 
(Aarhus University) report on behalf of a larger collaboration:

We observed the field of GRB 150711A (Bernardini et al. GCN 
18011) with the 2.5m Nordic Optical Telescope (NOT) equipped 
with AlFOSC starting at 21:18 UT (2.80 hrs after the trigger). 
The observation consisted of 3x300s in r-band and 3x300s in 
i-band and was performed at high airmass and with a seeing of 
~ 3". We do not detect any source within the XRT error box 
(Osborne et al. GCN 18012) down to a limiting magnitude of 
r ~ 21.5.

[GCN OPS NOTE(12jul15): Per author's request, a typo in the spelling
of VVN's name was corrected.]


GRB_name: GRB150711A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18015
SUBJECT: GRB 150711A: Fermi GBM detection
DATE:    15/07/12 02:08:36 GMT
FROM:    Peter Jenke at MSFC  <peter.a.jenke@nasa.gov>

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

"At 18:23:00.16 UT on July 11 2015, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 150711A (trigger 458331784/150711766),
which was also detected by 
Swift (M. G. Bernardini (INAF-OAB) et al. 2015, GCN 18011). 
The GBM on-ground location, using the Fermi GBM trigger
data, is consistent with the Swift/XRT location.  

The angle of the burst direction to the Fermi LAT boresight
 is 28 degrees.

The GBM light curve is a single peak with a 
duration (T90) of about 14s (50-300 keV).
The time-averaged spectrum from T0-13s to T0+19s 
is well fit by a power law with an exponential high-energy cutoff. 
The power law index is -1.16 +/- 0.07
and the cutoff energy, parameterized as Epeak, is 117 +/- 10 keV. 

The event fluence (10-1000 keV) in this time interval is
(2.8 +/- 0.06)E-06 ergs/cm^2. The 1.0-sec peak photon flux measured
starting from T0+4.7s in the 10-1000 keV band
is 4.1 +/- 0.2 ph/s/cm^2.

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


GRB_name: GRB150711A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18016
SUBJECT: GRB 150711A: Swift-XRT refined Analysis
DATE:    15/07/12 06:35:56 GMT
FROM:    Maria Grazia Bernardini at INAF/Brera  <grazia.bernardini@brera.inaf.it>

M.G. Bernardini, A. Melandri, P. D'Avanzo (INAF-OAB) and P.A. Evans
(Leicester) report on behalf of the Swift-XRT team:

We have analysed 6.9 ks of XRT data for GRB 150711A (Bernardini et al.
GCN Circ. 18011), from 96 s to 28.3 ks after the  BAT trigger. The data
comprise 115 s in Windowed Timing (WT) mode (the first 9 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Osborne et
al. (GCN Circ. 18012).

The light curve can be modelled with an initial power-law decay with an
index of alpha=2.90 (+0.17, -0.13), followed by a break at T+446 s to
an alpha of 0.62 (+0.07, -0.06). Flaring activity is observed between
T+150 s and T+225 s.

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.71 (+/-0.14). The
best-fitting absorption column is  4.2 (+/-0.5) x 10^21 cm^-2, in
excess of the Galactic value of 8.2 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 2.20 (+0.19, -0.18)
and a best-fitting absorption column of 4.2 (+0.9, -0.8) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 3.5 x 10^-11 (6.3 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      4.2 (+0.9, -0.8) x 10^21 cm^-2
Galactic foreground: 8.2 x 10^20 cm^-2
Excess significance: 6.8 sigma
Photon index:      2.20 (+0.19, -0.18)

If the light curve continues to decay with a power-law decay index of
0.62, the count rate at T+24 hours will be 0.022 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.8 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/00648601.

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

[GCN OPS NOTE(12jul15): Per MGB's request, AM, PDA, and PAE
were added to the author list.]


GRB_name: GRB150711A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18017
SUBJECT: GRB 150711A: Swift/UVOT Upper Limits
DATE:    15/07/12 09:05:59 GMT
FROM:    Paul Kuin at MSSL  <npkuin@gmail.com>

N. P. M. Kuin (UCL-MSSL) and M. G. Bernardini (INAF-OAB) report
on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150711A
117 s after the BAT trigger (Bernardini et al., GCN Circ. 18011).
No optical afterglow consistent with the XRT position (Osborne et al.
GCN Circ. 18012)  is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

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

white_FC           117          267          147         >21.4
u_FC               330          580          246         >20.2
white              117          909          235         >21.9
v                  660          852           39         >19.0
b                  585          778           39         >19.9
u                  330          753          265         >20.2
w1                 709          729           19         >18.8
m2                 684          704           19         >18.9
w2                 636          828           39         >18.8

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.09 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB150710B
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18018
SUBJECT: GRB 150710B: Swift-XRT and Swift-UVOT observations
DATE:    15/07/12 10:43:27 GMT
FROM:    Andrea Melandri at INAF-OAB  <andrea.melandri@brera.inaf.it>

A. Melandri (INAF-OAB), P. Kuin (MSSL-UCL), V. D'Elia (ASDC), A. D'ai
(INAF-IASFPA), L.M. McCauley (PSU), J.A. Kennea (PSU), B. Sbarufatti
(INAF-OAB/PSU), K.L. Page (U. Leicester), C. Pagani (U. Leicester),
A.P. Beardmore (U. Leicester), A. Maselli (INAF-IASFPA) and P.A. Evans
(U. Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has performed follow-up observations of the
Swift/BAT-detected burst GRB 150710B (Cummings et al. GCN Circ. 18009),
collecting 2.8 ks of Photon Counting (PC) mode data between T0+115.2 ks
and T0+121.6 ks. 

An uncatalogued X-ray source has been detected close to the refined
Swift/BAT error region (Cummings et al. GCN Circ. 18013), it is below
the RASS limit and shows no definitive signs of fading. Therefore, at
the present time we cannot confirm this as the afterglow. Details of
this source are given below:

  RA (J2000):  83.2176  =  05:32:52.23
  Dec (J2000): -46.9423  =  -46:56:32.4
  Error: 4.7 arcsec (radius, 90% conf.)
  Count-rate: 0.0141 [+0.0031, -0.0027] ct s^-1

The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
http://www.swift.ac.uk/ToO_GRBs/00020542.

Simultaneous with the Swift-XRT, the Swift-UVOT observed the field
of GRB 150710B. Preliminary 3-sigma upper limits using the UVOT
photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373)
for the first finding chart (FC) exposure and subsequent exposures are:


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

white        115375     120586    662        >21.1
v        115594     121561    957        >19.5
u        115157     120072    915        >20.5

The magnitudes in the table 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).

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


GRB_name: GRB150710B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18019
SUBJECT: Konus-Wind observation of GRB 150710B
DATE:    15/07/12 13:43:03 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

The long-duration GRB 150710B (Swift-BAT ground detection:
Cummings et al., GCN 18009)
triggered Konus-Wind at T0=29133.922 s UT (08:05:33.922).

The KW light curve shows a multi-peaked emission complex with
a total duration of ~8.5 s.
The emission is visible up to ~5 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB150710_T29133/

As observed by Konus-Wind, the burst had a fluence
of 1.1(-0.2,+0.2)x10^-5 erg/cm2, and a 64-ms peak flux,
measured from T0+4.032 s, of 6.8(-1.3,+1.2)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum (measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.81 (-0.23,+0.30),
the high energy photon index beta = -2.27 (-0.33,+0.18),
the peak energy Ep = 154 (-30,+37) keV,
chi2 = 75/97 dof.

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


GRB_name: GRB150711A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18020
SUBJECT: GRB 150711A: Swift-BAT refined analysis
DATE:    15/07/12 14:56:26 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <james.r.cummings@nasa.gov>

H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC),  J. R. Cummings (CPI),
N. Gehrels (GSFC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
  
Using the data set from T-240 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 150711A (trigger #648601)
(Bernardini, et al., GCN Circ. 18011).  The BAT ground-calculated position is
RA, Dec = 221.624, -35.464 deg which is
    RA(J2000)  =  14h 46m 29.7s
    Dec(J2000) = -35d 27' 49.9"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 32%.
  
The mask-weighted light curve shows a cusp-shaped main peak with smaller
preceding and following peaks, each about 20 seconds long.  Emission was
detectable from T-40 to T+70.  T90 (15-350 keV) is 64.2 +- 14.2 sec (estimated
error including systematics).
  
The time-averaged spectrum from T-34.1 to T+70.2 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.79 +- 0.08.  The fluence in the 15-150 keV band is 4.3 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+1.98 sec in the 15-150 keV band
is 3.8 +- 0.4 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/648601/BA/


GRB_name: GRB150710B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18022
SUBJECT: GRB 150710B: Swift-XRT afterglow detection
DATE:    15/07/13 15:04:58 GMT
FROM:    Andrea Melandri at INAF-OAB  <andrea.melandri@brera.inaf.it>

A. Melandri, P. D'Avanzo, M.G. Bernardini (INAF-OAB), K.L. Page, P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has conducted further observations of the field of the Swift/BAT-detected burst GRB 150710B (Cummings et al. GCN Circ. 18009). The observations now extend from T0+115 ks to T0+259 ks.

The source reported by Melandri et al. (GCN Circ. 18018) has significantly faded between two epochs, down to a level of (7 +/- 2)e-3 cts/s, and is therefore the GRB afterglow.

The results of the full analysis of the XRT observations are available at http://www.swift.ac.uk/ToO_GRBs/00020542.

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


GRB_name: GRB150716A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18027
SUBJECT: GRB 150716A: Swift detection of a burst
DATE:    15/07/16 07:19:03 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

D. Kocevski (NASA/GSFC/ORAU), A. Y. Lien (GSFC/UMBC),
A. Maselli (INAF-IASFPA), P. T. O'Brien (U Leicester),
K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU)
report on behalf of the Swift Team:

At 07:06:43 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 150716A (trigger=649157).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 278.466, -13.017 which is 
   RA(J2000) = 18h 33m 52s
   Dec(J2000) = -13d 01' 00"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a complex
structure with a duration of about 30 sec.  The peak count rate
was ~2000 counts/sec (15-350 keV), at ~5 sec after the trigger. 

The XRT began observing the field at 07:08:01.2 UT, 78.1 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 278.4873, -12.9787 which is equivalent to:
   RA(J2000)  = +18h 33m 56.95s
   Dec(J2000) = -12d 58' 43.3"
with an uncertainty of 5.3 arcseconds (radius, 90% containment). This
location is 156 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 1.36e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 127 seconds with the White filter
starting 86 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. Because of the density of catalogued stars, further
analysis is required to report an upper limit for any afterglow in the
sub-image. The 8'x8' region for the list of sources generated on-board covers
0.00% 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. No correction has been made for the large, but uncertain extinction
expected. 

Burst Advocate for this burst is D. Kocevski (dankocevski 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: GRB150716A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18028
SUBJECT: GRB 150716A: RATIR Optical Observations
DATE:    15/07/16 17:23:37 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC), William 
H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), 
J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara 
(ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico 
Ramirez-Ruiz (UCSC), Jos A. de Diego (UNAM), Leonid Georgiev (UNAM), 
Jess Gonzlez (UNAM), Carlos Romn-Ziga (UNAM), Neil Gehrels (GSFC), 
and Harvey Moseley (GSFC) report:

We observed the field of GRB 150716A (Kocevski et al., GCN 18027) with the 
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 
1.5m Harold Johnson Telescope at the Observatorio Astronmico Nacional on 
Sierra San Pedro Mrtir from 2015/07 16.30 to 2015/07 16.45 UTC (0.06 to 
3.61 hours after the BAT trigger), obtaining a total of 2.21 hours 
exposure in the r and i bands.

The field is crowded. Nevertheless, we detect a candidate optical 
afterglow within but close to the edge of the unenhanced Swift-XRT error 
circle at 18:33:57.20 -12:58:40.1 (J2000, 0.5"). In comparison with the 
USNO-B1 and 2MASS catalogs, we obtain the following detections:

  r 20.34  0.02
  i 19.23  0.02

At the moment, we have no information on fading, but further observations 
are
planned.

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.

We thank the staff of the Observatorio Astronmico Nacional in San Pedro
Mrtir.


GRB_name: GRB150716A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18029
SUBJECT: GRB 150716A: P60 Candidate Optical Afterglow
DATE:    15/07/16 21:02:36 GMT
FROM:    S. Bradley Cenko at NASA/GSFC  <brad.cenko@nasa.gov>

S. B. Cenko (NASA/GSFC) and D. A. Perley (DARK) report on behalf of a larger collaboration:

We have imaged the location of the X-ray afterglow of GRB 150716A (Kocevski et al., GCN 18027) with the automated Palomar 60 inch telescope.  Observations were obtained in the r, i, and z filters beginning at 07:11 UT (~ 4 minutes after the Swift trigger time) and ending at 8:18 UT.  Within the XRT error circle, we detect a large number of sources, one of which shows marginal evidence for fading:

  RA: 18:33:57.13
  Dec: -12:58:46.3

By comparison with the nearby USNO-B1 catalog star 0770-0591035 (I2 magnitude = 17.66), we measure the following magnitudes for this source:

UT          Magnitude
----------------------------------
07:11      21.48 +/- 0.22
08:17      > 22.15 

The source reported by RATIR (Watson et al, GCN 18028) is clearly detected in our images, but a) does not appear to fade, and b) is outside the revised XRT error circle.

We thank Alan Watson and Nat Butler for sharing the RATIR images with us.


GRB_name: GRB150716A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18030
SUBJECT: GRB 150716A: Swift-XRT refined Analysis
DATE:    15/07/17 07:19:04 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), T.G.R. Roegiers
(PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), B.P.
Gompertz (U. Leicester), A. Maselli  (INAF-IASFPA), A. Melandri
(INAF-OAB), P. D'Avanzo (INAF-OAB) and D. Kocevski report on behalf of
the Swift-XRT team:

We have analysed 3.6 ks of XRT data for GRB 150716A (Kocevski et al.
GCN Circ. 18027), from 66 s to 22.7 ks after the  BAT trigger. The data
comprise 126 s in Windowed Timing (WT) mode (the first 11 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The refined XRT position is RA, Dec = 278.4879, -12.9802 which is
equivalent to:

RA (J2000): 18 33 57.10
Dec(J2000): -12 58 48.9

with an uncertainty of 4.1 arcsec (radius, 90% confidence).

The light curve can be modelled with a power-law decay with a decay
index of alpha=1.67 (+0.08, -0.06).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.67 (+0.25, -0.23). The
best-fitting absorption column is  1.35 (+0.24, -0.22) x 10^22 cm^-2,
in excess of the Galactic value of 7.0 x 10^21 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.6 x 10^-11 (1.4 x 10^-10) erg
cm^-2 count^-1. 

A summary of the WT-mode spectrum is thus:
Total column:      1.35 (+0.24, -0.22) x 10^22 cm^-2
Galactic foreground: 7.0 x 10^21 cm^-2
Excess significance: 4.8 sigma
Photon index:      2.67 (+0.25, -0.23)

If the light curve continues to decay with a power-law decay index of
1.67, the count rate at T+24 hours will be 2.4 x 10^-4 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.8 x
10^-15 (3.5 x 10^-14) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00649157.

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


GRB_name: GRB150716A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18032
SUBJECT: GRB 150716A: Continued RATIR Optical Observations
DATE:    15/07/17 18:44:52 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC), William 
H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), 
J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara 
(ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico 
Ramirez-Ruiz (UCSC), Jos A. de Diego (UNAM), Leonid Georgiev (UNAM), 
Jess Gonzlez (UNAM), Carlos Romn-Ziga (UNAM), Neil Gehrels (GSFC), 
and Harvey Moseley (GSFC) report:

We observed the field of GRB 150716A (Kocevski et al., GCN 18027) with the 
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 
1.5m Harold Johnson Telescope at the Observatorio Astronmico Nacional on 
Sierra San Pedro Mrtir from 2015/07 17.16 to 2015/07 17.46 UTC (20.69 to 
27.82 hours after the BAT trigger), obtaining a total of 4.31 hours 
exposure in the r and i bands.

In these observations, the source reported by Watson et al. (GCN 18028) is 
detected with

r 20.43  0.02
i 19.89  0.02

These magnitudes are in the AB system and are not corrected for Galactic 
extinction in the direction of the GRB.

While these formal errors would suggest a slight fading compared to the 
first night, in a crowded field such as this one, the real errors in the 
photometry are likely to be much larger than these formal errors of 0.02 
mag. We feel that there is no strong evidence for fading. Also, as noted 
by Cenko & Perley (GCN 18029), this source is significantly outside the 
enhanced XRT error region reported by Sbarufatti et al. (GCN 18030). We 
therefore conclude that it is not the afterglow.

We see no evidence for the source reported by Cenko & Perley (GCN 18029) 
in any of our images. However, this is not unexpected, since our images 
have significantly worse image quality than theirs.

We thank the staff of the Observatorio Astronmico Nacional in San Pedro 
Mrtir.


GRB_name: GRB150716A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18033
SUBJECT: GRB 150716A: Swift/UVOT Upper Limits
DATE:    15/07/17 21:08:31 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@swift.psu.edu>

S. J. LaPorte (PSU) and D. Kocevski (NASA/GSFC/ORAU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150716A
86 s after the BAT trigger (Kocevski et al., GCN Circ. 18027).
No optical afterglow consistent with the enhanced XRT position
(Sbarufatti et al. GCN Circ. 18030)
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

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

white (fc)          86          213          125         >19.8
white            11701        12468          747         >21.11
v                 5994         6193          196         >18.62
b                 5378        22713         1512         >20.86
u                 6608         6721          111         >19.17
uvw1              6404         6603          196         >19.38
uvm2              6198         6398          196         >19.38
uvw2              5789         5989          196         >19.61
 
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 1.43 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB150716A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18034
SUBJECT: GRB 150716A: Swift-BAT refined analysis
DATE:    15/07/17 22:22:06 GMT
FROM:    Tilan Ukwatta at LANL  <tilan.ukwatta@gmail.com>

A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC),
D. Kocevski (NASA/GSFC/ORAU), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL)
(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 150716A (trigger #649157) (Kocevski, et al.,
GCN Circ. 18027). The BAT ground-calculated position is
RA, Dec = 278.481, -12.978 deg which is
   RA(J2000)  =  18h 33m 55.4s
   Dec(J2000) = -12d 58' 40.8"
with an uncertainty of 1.1 arcmin, (radius, sys+stat,
90% containment). The partial coding was 91%.

BAT light curve shows a single peak starting around T+5 sec
and ending around T+60 sec. T90 (15-350 keV) is
44 +- 6 sec (estimated error including systematics).

The time-averaged spectrum from T-4.19 to T+50.02 sec is
best fit by a simple power-law model.  The power law index
of the time-averaged spectrum is 1.54 +- 0.10.  The fluence
in the 15-150 keV band is 1.5 +- 0.1 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T+9.69 sec in the
15-150 keV band is 0.8 +- 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/649157/BA/


GRB_name: GRB150711A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18035
SUBJECT: GRB 150711A: Burakan-ISON optical observations
DATE:    15/07/18 22:00:01 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI), V. Nevskiy (ISON) I. Molotov (KIAM), A. Pozanenko 
(IKI) report on behalf of larger GRB follow-up collaboration:

We observed the field of GRB 150711A (Bernardini et al. GCN 18011) with 
the 40 cm telescope of Burakan-ISON observatory starting on Jul., 11 
(UT) 18:36:16, i.e. ~13 min after burst trigger. We obtained several 
unfiltered images. In a combined image we  do not detect any source 
within the XRT error box (Osborne et al. GCN 18012) down to a limiting 
magnitude of R = 16.9

Date       UT start  t-T0      Filter   Exp.  OT    UL(3 sigma)
                     (mid, days)         (s)

2015-07-11 18:36:16  0.01250   none     9*60  n/d   16.9

The photometry is based on nearby USNO-B1.0  stars.


GRB_name: GRB150716A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18036
SUBJECT: GRB 150716A: KAIT Optical Upper Limit
DATE:    15/07/20 03:54:00 GMT
FROM:    Xiang-Gao Wang at GuangXi U  <wangxg@gxu.edu.cn>

Xianggao Wang (UC Berkeley, GXU, UNLV), WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on 
behalf of the KAIT GRB team:  The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, responded to Swift GRB 150716A (Kocevski et al., GCN 18027) starting at 07:10:08 UT, 195 s after the burst. Observations were performed with an automatic sequence in the clear (roughly R), V, and I filters, and the exposure time was 20 s per image. After combining 6 x 20 s clear-band images, we do not detect the optical source reported by Cenko et al. (GCN 18029), nor any other new source within the XRT error circle (Sbarufatti et al., GCN 18030). The upper limit is estimated to be about 20.9 mag at a mean time of 443 s after the trigger, calibrated to USNO B1.0.








  


GRB_name: GRB150720A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18037
SUBJECT: Swift Trigger 649706: a possible GRB or bright Galactic transient
DATE:    15/07/20 14:29:11 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

E. Sonbas (NASA/GSFC/Adiyaman Univ.), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), D. N. Burrows (PSU),
S. B. Cenko (GSFC), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC),
S. L. Gibson (U Leicester), L. Izzo (URoma/ICRA), J. A. Kennea (PSU),
A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC),
A. Maselli (INAF-IASFPA), K. L. Page (U Leicester),
B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf
of the Swift Team:

At 14:02:09 UT, the Swift Burst Alert Telescope (BAT) triggered and
located possible GRB 150720A (trigger=649706).  Swift slewed immediately
to the burst.  The BAT on-board calculated location is 
RA, Dec 119.582, -28.301, which is 
   RA(J2000)  =  07h 58m 20s
   Dec(J2000) = -28d 18' 02"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  As is typical for image trigger (64-sec), there
is nothing significant in the real-time TDRSS light curve. 

The XRT began observing the field at 14:04:23.7 UT, 134.6 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source with an enhanced position: RA, Dec
119.5810, -28.2623 which is equivalent to:
   RA(J2000)  = 07h 58m 19.45s
   Dec(J2000) = -28d 15' 44.2"
with an uncertainty of 2.2 arcseconds (radius, 90% containment). This
location is 139 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 5.72
x 10^21 cm^-2 (Willingale et al. 2013). 

The initial flux in the 0.1 s image was 2.93e-08 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 142 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 large, but uncertain extinction expected. 

The event is near the galactic plane (l=245, b=0.5) and has a rapid 
decrease in X-ray afterglow.  Also, it was a faint image trigger in 
BAT but very bright in X-rays.  We can not rule out that the source 
is a galactic transient instead of a gamma-ray burst. 

Burst Advocate for this burst is E. Sonbas (edasonbas AT yahoo.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: GRB150720A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18038
SUBJECT: GRB 150720A: Swift-BAT refined analysis
DATE:    15/07/21 11:56:34 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU), E. Sonbas (NASA/GSFC/Adiyaman Univ.),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
 
Using the data set from T-30 to T+273 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 150720A (trigger #649706)
(Sonbas, et al., GCN Circ. 18037).  The BAT ground-calculated position is
RA, Dec = 119.577, -28.281 deg, which is 
   RA(J2000)  =   07h 58m  18.5s
   Dec(J2000) =  -28d 16'  50"
with an uncertainty of 1.5  arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.
 
The mask-weighted light curve shows 3 peaks starting at T-30 sec
and the emission ending at ~T+130 sec.
T90 (15-350 keV) is 151 +- 11 sec (estimated error including systematics).
 
The time-averaged spectrum from T-35.1 to T+126.4 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.61 +- 0.33.  The fluence in the 15-150 keV band is 5.6 +- 1.0 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+116.68 sec in the 15-150 keV band
is 0.3 +- 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/649706/BA/

We note that this has a soft spectrum (in the bottom ~10-percentile
of the BAT hardness range) and that the Galactic lattitude is 0.5deg,
so we can not rule out a non-GRB Galactic source origin for this event.


GRB_name: GRB150720A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18039
SUBJECT: GRB 150720A: Swift-XRT refined Analysis
DATE:    15/07/21 15:27:06 GMT
FROM:    Valerio D'Elia at ASDC  <delia@asdc.asi.it>

V. D'Elia (ASDC), L. Izzo (URoma/ICRA), K. Page (U Leicester) and E. Sonbas (NASA/GSFC/Adiyaman Univ.) report on behalf of the Swift-XRT team:

We have analysed 11 ks of XRT data for the possible GRB 150720A (Sonbas et al.  GCN Circ. 18037), from 138 s to 40 ks after the BAT trigger. The data comprise 96 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The refined XRT position is RA, Dec = 119.58144, -28.26249 which is equivalent to:

RA (J2000): 07 58 19.55
Dec(J2000): -28 15 45.0

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

The late time light curve can be modelled with a power-law decay with a decay index of alpha ~ 1.5.

A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 3.16 (+0.10, -0.10). The best-fitting absorption column is 3.1 (+0.6, -0.6) x 10^21 cm^-2, in excess of the Galactic value of 5.72 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 2.7 x 10^-11 (1.6 x 10^-10) erg cm^-2 count^-1.

A summary of the WT-mode spectrum is thus:
Total column:      8.8 (+0.6, -0.6) x 10^21 cm^-2
Galactic foreground: 5.72 x 10^21 cm^-2
Excess significance: 5.1 sigma
Photon index:      3.16 (+0.10, -0.10)

If the light curve continues to decay with a power-law decay index of 1.5, the count rate at T+24 hours will be 1.8 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.9 x 10^-14 (2.9 x 10^-13) erg cm^-2 s^-1.

Given the light curve and spectrum behaviour, we believe that this is a real GRB and not a galactic transient.

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


GRB_name: GRB150720A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18040
SUBJECT: GRB 150720A: Enhanced Swift-XRT position
DATE:    15/07/21 15:41:17 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 653 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 150720A, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 119.58146, -28.26251 which is equivalent
to:

RA (J2000): 07h 58m 19.55s
Dec (J2000): -28d 15' 45.0"

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: GRB150721A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18041
SUBJECT: GRB 150721A: Fermi GBM detection
DATE:    15/07/21 20:55:52 GMT
FROM:    Elisabetta Bissaldi at U.Innsbruk/IAPP  <Elisabetta.Bissaldi@uibk.ac.at>

E. Bissaldi (INFN Bari), V. Connaughton (USRA) and
A. von Kienlin (MPE) report on behalf of the Fermi GBM Team:


At 05:49:08.93 UT on 21 July 2015, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 150721A (trigger 459150552/150721242).

The on-ground calculated location, using the GBM trigger
data, is

RA= 334.1, DEC = +7.8
(J2000 degrees, equivalent to 22h 16m, 07d 48')

with an uncertainty of 1.5 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).

The trigger resulted in an Autonomous Repoint Request (ARR)
by the GBM Flight Software owing to the high peak flux of the GRB.
This was accepted and the spacecraft slewed to the GBM in-flight
location. The initial angle from the Fermi LAT boresight
is 63 degrees.

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

The GBM light curve consists of a first peak at trigger
time followed by a very soft peak around 100 s.
The duration (T90) is about 20 s (50-300 keV).
The time-averaged spectrum from T0 to T0+20.2 s
is best fit by a smoothly broken power law function.
The low-energy index is -0.58 +/- 0.06, the high-energy
index is -2.90 +/- 0.06 and the break energy
is 45.7 +/- 2.3 keV.

The event fluence (10-1000 keV) in this time interval is
(1.52 +/- 0.08)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+5.4 s in the 10-1000 keV band
is 16.7 +/- 0.3 ph/s/cm^2.

A Band function fits the spectrum equally well
with Epeak = 56.26 +/- 1.15 keV,
alpha = -0.16 +/- 0.07, and beta = -2.74 +/- 0.05.


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


GRB_name: GRB150722A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18042
SUBJECT: GRB 150722A: Swift detection of a burst
DATE:    15/07/22 10:10:55 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC), S. D. Barthelmy (GSFC),
D. N. Burrows (PSU), J. R. Cummings (NASA/UMBC) and
K. L. Page (U Leicester) report on behalf of the Swift Team:

At 09:57:53 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 150722A (trigger=649916).  Swift did not slew immediately
due to earth limb observing constraint.  The BAT on-board calculated location is 
RA, Dec 218.272, -35.197 which is 
   RA(J2000)  =  14h 33m 05s
   Dec(J2000) = -35d 11' 46"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  As is usual for an image trigger (64-sec),
there is nothing significant in the real-time TDRSS light curve. 

Due to an observing constraint, Swift will not slew until T0+50.9
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: GRB150722A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18043
SUBJECT: GRB 150722A: Swift-XRT observations
DATE:    15/07/22 12:06:05 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

S. Campana (INAF-OAB), P.A. Evans (U. Leicester), J.P. Osborne (U.
Leicester), D.N. Burrows (PSU), J.A. Kennea (PSU) and G. Tagliaferri
(INAF-OAB) report on behalf of the Swift-XRT team:

The XRT began observing the field of GRB 150722A at 10:51:48.0 UT,
3234.9 seconds after the BAT trigger. Using promptly downlinked data we
find a fading, uncatalogued X-ray source located at RA, Dec 218.27775,
-35.19644 which is equivalent to:
   RA(J2000)  = 14h 33m 06.66s
   Dec(J2000) = -35d 11' 47.2"
with an uncertainty of 3.6 arcseconds (radius, 90% containment). This
location is 17 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 5.92
x 10^20 cm^-2 (Willingale et al. 2013). 


GRB_name: GRB150722A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18044
SUBJECT: GRB 150722A: Enhanced Swift-XRT position
DATE:    15/07/22 14:27:12 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 2194 s of XRT Photon Counting mode data and 6 UVOT
images for GRB 150722A, 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 = 218.27800, -35.19588 which is equivalent
to:

RA (J2000): 14h 33m 6.72s
Dec (J2000): -35d 11' 45.2"

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: GRB150720A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18045
SUBJECT: GRB 150720A: Swift/UVOT Upper Limits
DATE:    15/07/22 16:14:07 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@swift.psu.edu>

M. H. Siegel (PSU) and E. Sonbas (NASA/GSFC/Adiyaman Univ.)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150720A
142 s after the BAT trigger (Sonbas et al., GCN Circ. 18037).
No optical afterglow consistent with the XRT position (Beardmore et al.,
GCN Circ. 18040)  is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

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

white (fc)         142          292          147         >20.5
u (fc)             301          551          246         >20.4
white              142         1551          392         >21.2
v                  631         1601          117         >19.3
b                  557         1527           97         >19.6
u                  301         1502          324         >20.2
w1                 680         1478           97         >19.3
m2                 655         1623          114         >19.8
w2                 606         1577          117         >19.6

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.68 in the direction of the burst
(Schlegel et al. 1998).

[GCN OPS NOTE(22jul15): Added the "A" suffix to the GRB name.]


GRB_name: GRB150722A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18046
SUBJECT: GRB 150722A: Swift/UVOT Upper Limits
DATE:    15/07/22 16:38:01 GMT
FROM:    Paul Kuin at MSSL  <npkuin@gmail.com>

N. P. M. Kuin (UCL-MSSL) and F. E. Marshall (NASA/GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150722A
3238 s after the BAT trigger (Marshall et al., GCN Circ. 18042).
No optical afterglow consistent with the XRT position (Evans et al.
GCN Circ. No. 18044) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

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

white_FC          3238         3388          147         >20.6
white             3238         5442          541         >21.6
v                 4217         5791          333         >20.0
b                 3602         5237          393         >21.0
u                 3396         5031          393         >20.6
w1                4627         4827          197         >20.1
m2                4422         4622          197         >20.3
w2                4012         5647          393         >21.4

The magnitudes in the table 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).


GRB_name: GRB150722A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18047
SUBJECT: GRB 150722A: Swift-XRT refined Analysis
DATE:    15/07/22 20:57:16 GMT
FROM:    Alex Amaral-Rogers at U.of Leicester  <aar14@leicester.ac.uk>

D.N. Burrows (PSU), T.G.R. Roegiers (PSU), B.P. Gompertz (U.
Leicester), J.P. Osborne (U. Leicester), A. Melandri (INAF-OAB), P.
D'Avanzo (INAF-OAB), V. D'Elia (ASDC), L.M. McCauley (PSU), 
A. Amaral-Rogers (U. Leicester) and F. E. Marshall (NASA/GSFC) report
on behalf of the Swift-XRT team:

We have analysed 5.7 ks of XRT data for GRB 150722A (Marshall et al.
GCN Circ. 18042), from 3.2 ks to 17.3 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. 18044).

The light curve can be modelled with a power-law decay with a decay
index of alpha=0.90 (+0.14, -0.13).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.08 (+/-0.13). The
best-fitting absorption column is  1.4 (+0.4, -0.3) x 10^21 cm^-2, in
excess of the Galactic value of 5.9 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.2 x 10^-11 (4.3 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.4 (+0.4, -0.3) x 10^21 cm^-2
Galactic foreground: 5.9 x 10^20 cm^-2
Excess significance: 3.6 sigma
Photon index:      2.08 (+/-0.13)

If the light curve continues to decay with a power-law decay index of
0.90, the count rate at T+24 hours will be 0.013 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.2 x
10^-13 (5.6 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/00649916.

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


GRB_name: GRB150722A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18048
SUBJECT: GRB 150722A: Swift-BAT refined analysis
DATE:    15/07/22 23:51:39 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <james.r.cummings@nasa.gov>

C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),  J. R. Cummings (CPI),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC),
D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):

Using the data set from T-240 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 150722A (trigger #649916)
(Marshall, et al., GCN Circ. 18042).  The BAT ground-calculated position is
RA, Dec = 218.297, -35.196 deg which is
    RA(J2000)  =  14h 33m 11.3s
    Dec(J2000) = -35d 11' 45.1"
with an uncertainty of 2.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 94%.

The mask-weighted light curve shows weak, variable emission from prior to T-200
to about T+55 seconds.  T90 (15-350 keV) is 67 +- 12 sec (estimated error
including systematics).

The time-averaged spectrum from T-26.00 to T+48.00 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.79 +- 0.26.  The fluence in the 15-150 keV band is 6.1 +- 0.9 x 10^-07  erg/cm2.
The 1-sec peak photon flux measured from T+15.00 sec in the 15-150 keV band
is 0.4 +- 0.1 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/649916/BA/

[GCN OPS NOTE(22jul15): Per an author's request, the "T-60" was corrected
to "T-240".]


GRB_name: GRB150722A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18049
SUBJECT: GRB 150722A: LCOGT-Sutherland observations
DATE:    15/07/23 09:00:59 GMT
FROM:    Simone Dichiara at Ferrara U/Italy  <dichiara@fe.infn.it>

S. Dichiara, C. Guidorzi (U. Ferrara), D. Kopac (LJMU),
on behalf of a large collaboration report:

One of the LCOGT 1-m telescopes in Sutherland (South Africa)
began observing GRB 150722A (Marshall et al. GCN 18042)
on July 22 at 17:01:14 UT, i.e. ~7 hours after the BAT
trigger with the r' and i' filters.

Within the XRT error circle (Evans et al. GCN 18044)
we found no new source down to the following limit:

Mid time from  Total Exp   Filter    Magnitude
trigger (hr)   (s)
-------------------------------------------------
7.46           120x15        r'        > 20.0
7.90           120x6         i'        > 18.8
-------------------------------------------------

Values have been calibrated against nearby USNOB-1 stars
(R2 and I).


GRB_name: GRB150724A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18050
SUBJECT: GRB 150724A: Swift detection of a burst
DATE:    15/07/24 06:02:12 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

J. L. Racusin (NASA/GSFC), A. P. Beardmore (U Leicester),
J. R. Cummings (NASA/UMBC), K. L. Page (U Leicester),
D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the
Swift Team:

At 05:46:35 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 150724A (trigger=650141).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 97.540, -19.154 which is 
   RA(J2000) = 06h 30m 09s
   Dec(J2000) = -19d 09' 12"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed multiple peaks
structure with a duration of about 40 sec.  The peak count rate
was ~1412 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 05:48:18.6 UT, 102.6 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source located at RA, Dec 97.56060,
-19.16395 which is equivalent to:
   RA(J2000)  = 06h 30m 14.54s
   Dec(J2000) = -19d 09' 50.2"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 78 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 2.94
x 10^21 cm^-2 (Willingale et al. 2013). 

The initial flux in the 2.5 s image was 1.27e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 250 seconds with the U filter starting
108 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 19.2 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 18.0 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.27. 

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: GRB150724A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18052
SUBJECT: GRB 150724A: Prompt enhanced Swift-XRT position
DATE:    15/07/24 06:23:32 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Using  promptly downlinked XRT event data for GRB 150724A, we find an
enhanced XRT position of the afterglow: RA, Dec: 97.5600, -19.1646
which is equivalent to:
   RA (J2000)  = 06 30 14.41
   Dec (J2000) = -19 09 52.5
with an uncertainty of 2.0 arcseconds (radius, 90% confidence).
Analysis of the promptly available data is online at
http://www.swift.ac.uk/sper/650141.

Position enhancement is 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: GRB150724A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18054
SUBJECT: GRB 150724A: Enhanced Swift-XRT position
DATE:    15/07/24 11:32:50 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 2472 s of XRT Photon Counting mode data and 4 UVOT
images for GRB 150724A, 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 = 97.56044, -19.16479 which is equivalent
to:

RA (J2000): 06h 30m 14.51s
Dec (J2000): -19d 09' 53.3"

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: GRB150724A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18055
SUBJECT: GRB 150724A: Swift-BAT refined analysis
DATE:    15/07/24 12:10:27 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), J. L. Racusin (NASA/GSFC), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
 
Using the data set from T-240 to T+902 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 150724A (trigger #650141)
(Racusin, et al., GCN Circ. 18050).  The BAT ground-calculated position is
RA, Dec = 97.549, -19.147 deg, which is 
   RA(J2000)  =  06h 30m 11.7s 
   Dec(J2000) = -19d 08' 48.1" 
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 48%.
 
The mask-weighted light curve has at least 4 peaks starting at ~T-10 sec,
with peaks at ~T+1 sec, ~T+24 sec, ~T+160 sec, & ~T+220 sec, and the
emission ending at ~T+300 sec.  T90 (15-350 keV) is 280 +- 44 sec
(estimated error including systematics).
 
The time-averaged spectrum from T-1.07 to T+325.42 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.06 +- 0.15.  The fluence in the 15-150 keV band is 2.2 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+24.08 sec in the 15-150 keV band
is 0.9 +- 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/650141/BA/


GRB_name: GRB150724A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18057
SUBJECT: GRB 150724A: Swift/UVOT Upper Limits
DATE:    15/07/24 14:41:21 GMT
FROM:    Massimiliano de Pasquale at IASF-Palermo  <m.depasquale@ucl.ac.uk>

M. De Pasquale (UCL-MSSL) and J. L. Racusin (NASA/GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150724A
108 s after the BAT trigger (Racusin et al., GCN Circ. 18050).
No optical afterglow consistent with the XRT position (Goad et al.
GCN Circ. 18054) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent summed exposures are:

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

u_FC               108          358          246         >19.7

v                  415         6930          510         >19.2
b                  364        12898         1165         >20.6
u                  108        12238         1769         >20.7
w1                 464        11324         1387         >20.5
m2                 439         7135          502         >19.9
w2                 390         6726          529         >20.2

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.27 in the direction of the burst
(Schlegel et al. 1998).

-- 

Dr. Massimiliano De Pasquale
Research associate - Swift UVOT scientist
Mullard Space Science Laboratory, University College London


GRB_name: GRB150724A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18059
SUBJECT: GRB 150724A: Swift-XRT refined Analysis
DATE:    15/07/24 18:02:03 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

T.G.R. Roegiers (PSU), B.P. Gompertz (U. Leicester), J.P. Osborne (U.
Leicester), K.L. Page (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia
(ASDC), A. D'ai (INAF-IASFPA), L.M. McCauley (PSU), J.A. Kennea (PSU)
and J.L. Racusin report on behalf of the Swift-XRT team:

We have analysed 11 ks of XRT data for GRB 150724A (Racusin et al. GCN
Circ. 18050), from 91 s to 24.4 ks after the  BAT trigger. The data
comprise 349 s in Windowed Timing (WT) mode (the first 9 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Goad et al.
(GCN Circ. 18052). The late-time light curve (from T0+4.7 ks) is
consistent with a constant source of mean count rate 2.2e+00 ct/sec. A
power-law fit gives an index of -0.02 (+0.19, -0.20).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.70 (+/-0.04). The
best-fitting absorption column is  3.70 (+0.21, -0.20) x 10^21 cm^-2,
in excess of the Galactic value of 2.9 x 10^21 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 2.13 (+0.18, -0.17)
and a best-fitting absorption column of 3.6 (+0.8, -0.7) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 3.6 x 10^-11 (5.8 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      3.6 (+0.8, -0.7) x 10^21 cm^-2
Galactic foreground: 2.9 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:      2.13 (+0.18, -0.17)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00650141.

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


GRB_name: GRB150725A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18062
SUBJECT: GRB 150725A: MAXI/GSC detection
DATE:    15/07/25 09:50:41 GMT
FROM:    H. Negoro at Nihon U.  <negoro@phys.cst.nihon-u.ac.jp>

T. Masumitsu, H. Negoro, (Nihon U.), T. Sakamoto (AGU),
S. Ueno, H. Tomida, S. Nakahira, M. Kimura, M. Ishikawa, 
Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Serino, M. Shidatsu, J. Sugimoto, 
T. Takagi, M. Matsuoka (RIKEN), N. Kawai, T. Yoshii, Y. Tachibana (Tokyo Tech), 
A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, R.Imatani (Osaka U.), 
M. Nakajima, K. Tanaka (Nihon U.), Y. Ueda, T. Kawamuro, 
T. Hori (Kyoto U.), Y. Tsuboi, S. Kanetou (Chuo U.), M. Yamauchi, D. Itoh (Miyazaki U.), 
K. Yamaoka (Nagoya U.), M. Morii (ISM)
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source 
at UT 08:45:00 UT. 
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (220.422 deg, -2.421 deg) = (14 41 41, -02 25 15) (J2000) 
with a statistical 90% C.L. elliptical error region 
with long and short radii of 0.11 deg and 0.09 deg, respectively. 
The roll angle of long axis from the north direction is 117.0 deg counterclockwise. 
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
The X-ray flux averaged over the scan was 1491 +- 107 mCrab
(4-10keV, 1 sigma error).

Without assumptions on the source constancy, we obtain a rectangular error
box for the transient source with the following corners:
(R.A., Dec) = (220.229 deg, -2.781 deg) = (14 40 55, -02 46 51) (J2000)
(R.A., Dec) = (220.058 deg, -2.639 deg) = (14 40 14, -02 38 20) (J2000)
(R.A., Dec) = (220.615 deg, -2.060 deg) = (14 42 27, -02 03 36) (J2000)
(R.A., Dec) = (220.786 deg, -2.201 deg) = (14 43 08, -02 12 04) (J2000)
There was no significant excess flux in the previous transit at 07:12 UT
with an upper limit of 20 mCrab.


GRB_name: GRB150724B
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18065
SUBJECT: GRB 150724B: Fermi-LAT detection
DATE:    15/07/25 13:52:53 GMT
FROM:    Judith Racusin at GSFC  <judith.racusin@nasa.gov>

E. Bissaldi (INFN Bari), J. L. Racusin (NASA/GSFC), and E. Moretti (MPP Munich) 
report on behalf of the Fermi-LAT team: 

At 18:45:36.71 on 2015-07-24, Fermi-LAT detected high-energy emission from GRB 150724B, 
which was also detected by Fermi-GBM (trigger 459456340/150724782). 

The best LAT on-ground location is found to be

RA, Dec = 351.92, 3.67 (J2000) 

with an error radius of 0.3 deg (90% containment, systematic error only). This was 58 deg 
from the LAT boresight at the time of the trigger.

The data from the Fermi-LAT show a ~5 sigma increase in the event rate within 7 degrees 
of the GBM location after the GBM trigger that is spatially and temporally correlated with the 
GBM emission. More than 11 photons above 100 MeV and 1 photons above 1 GeV were 
observed within 300 seconds. The highest-energy photon is a 2 GeV event which is 
observed ~50 seconds after the GBM trigger.

A Swift ToO has been requested for this burst.

The Fermi-LAT point of contact for this burst is Elisabetta Bissaldi (elisabetta.bissaldi@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.


GRB_name: GRB150724B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18066
SUBJECT: GRB 150724B: Fermi GBM detection
DATE:    15/07/25 16:22:15 GMT
FROM:    Peter Veres at ELTE,Budapest  <veresp@gmail.com>

P. Veres (UAH), V. Connaughton (USRA) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 18:45:37.714 UT on 24 July 2015, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 150724B (trigger 459456341 / 150724782)
which was also detected by the Fermi/LAT (Bissaldi et al. 2008, GCN
18065). The GBM on-ground location is consistent with the Fermi/LAT
position.


The on-ground calculated location, using the GBM trigger
data, is RA = 350.92, DEC = +10.160 (J2000 degrees,
equivalent to 23h 24m, 10d 10'), with an uncertainty
of 1.05 degrees (radius, 1-sigma containment,
statistical only).


The GBM light curve consists of two emission episodes
with a total duration (T90) of about 38 s (50-300 keV).
The time-averaged spectrum from T0-6.1 s to T0+46 s is
adequately fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.75 +/- 0.02 and
the cutoff energy, parameterized as Epeak, is 729 +/- 35 keV.


The event fluence (10-1000 keV) in this time interval is
(3.55 +/- 0.04)E-5 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+40 s in the 8-1000 keV band is 8.3 +/- 0.2 ph/s/cm^2.


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


GRB_name: GRB150724B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18068
SUBJECT: GRB 150724B: Swift ToO observations
DATE:    15/07/25 19:24:14 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift has initiated a ToO observation of the Fermi/LAT GRB 150724B. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020543

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the Fermi/LAT event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a 
GCN Circular after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

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


GRB_name: GRB150724B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18069
SUBJECT: GRB 150724B: Swift-XRT observations
DATE:    15/07/26 05:24:25 GMT
FROM:    Kim Page at U.of Leicester  <kpa@star.le.ac.uk>

J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U.
Leicester), V. D'Elia (ASDC), A. D'ai (INAF-IASFPA), A. Maselli 
(INAF-IASFPA), L.M. McCauley (PSU), J.A. Kennea (PSU), B. Sbarufatti
(INAF-OAB/PSU) and P.A. Evans (U. Leicester) report on behalf of the
Swift-XRT team:

Swift-XRT has performed follow-up observations of the
Fermi/LAT-detected burst GRB 150724B (Bissaldi et al. GCN Circ. 18065),
collecting 1.8 ks of Photon Counting (PC) mode data between T0+94.4 ks
and T0+96.2 ks. 

One uncatalogued X-ray source has been detected, it is below the RASS
limit and shows no definitive signs of fading. Therefore, at the
present time we cannot confirm this as the afterglow. Details of this
source are given below:

Source 1:
  RA (J2000):  351.8904  =  23:27:33.70
  Dec (J2000): +3.8186  =  +03:49:06.8
  Error: 4.3 arcsec (radius, 90% conf.)
  Count-rate: 0.0143 +/- 0.0033 ct s^-1
  Flux: (4.6 +/- 1.1)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
http://www.swift.ac.uk/ToO_GRBs/00020543.

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


GRB_name: GRB150724B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18072
SUBJECT: GRB 150724B: RATIR Optical Observations
DATE:    15/07/27 03:33:50 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William 
H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), 
J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara 
(ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico 
Ramirez-Ruiz (UCSC), Jos A. de Diego (UNAM), Leonid Georgiev (UNAM), 
Jess Gonzlez (UNAM), Carlos Romn-Ziga (UNAM), Neil Gehrels (GSFC), 
and Harvey Moseley (GSFC) report:

We observed the field of the LAT GRB 150724B (Bissaldi et al., GCN 18065) 
with the Reionization and Transients Infrared Camera (RATIR; 
www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio 
Astronmico Nacional on Sierra San Pedro Mrtir from 2015/07 26.28 to 
2015/07 26.48 UTC (36.02 to 40.86 hours after the BAT trigger), obtaining 
a total of 2.39 hours exposure in the r and i bands.

For a source within the Swift XRT error circle (Osborne et al., GCN 
18069), in comparison with the SDSS DR9 catalog, we obtain the following 
detections:

   r 23.24 +/- 0.34
   i 22.39 +/- 0.15

These magnitudes are in the AB system and are not corrected for Galactic 
extinction in the direction of the GRB.

At this moment we have no information on fading. Further observations are 
planned.

We thank the staff of the Observatorio Astronmico Nacional in San Pedro 
Mrtir.


GRB_name: GRB150725A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18073
SUBJECT: Konus-Wind observation of GRB 150725A
DATE:    15/07/27 09:11:27 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

The long-duration GRB 150725A (Masumitsu et al., GCN Circ. 18062) 
triggered Konus-Wind at T0=31454.410 s UT (08:44:14.410),
~15 s before the MAXI trigger.

The KW light curve measured in the triggered mode shows multiple
bright pulses in the interval from ~T0-0.5 s to ~T0+60 s.
The emission is visible up to ~10 MeV.

As observed by Konus-Wind, the burst had a fluence
of 1.55(-0.10,+0.09)x10^-4 erg/cm2, and a 64-ms peak flux,
measured from T0+51.456 s, of 1.35(-0.23,+0.17)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum (measured from T0 to T0+58.112 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.84 (-0.07,+0.08),
the high energy photon index beta = -2.32 (-0.13,+0.10),
the peak energy Ep = 326 (-24,+28) keV,
chi2 = 125/97 dof.

The spectrum near the peak count rate
(measured from T0+51.200 to T0+58.112 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.77 (-0.23,+0.26),
the high energy photon index beta = -2.29 (-0.52,+0.18),
the peak energy Ep = 270 (-53,+86) keV,
chi2 = 92/97 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB150725_T31454/

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


GRB_name: GRB150724B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18074
SUBJECT: Konus-Wind observation of GRB 150724B
DATE:    15/07/27 14:09:55 GMT
FROM:    Anastasia Tsvetkova at Ioffe Institute  <tsvetkova@mail.ioffe.ru>

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

The long-duration, hard-spectrum GRB 150724B
(Fermi-LAT detection: Bissaldi, Racusin & Moretti, GCN 18065;
Fermi GBM detection: Veres, Connaughton & Meegan, GCN 18066)
triggered Konus-Wind at T0=67574.792 s UT (18:46:14.792).

The burst light curve shows  a double-peaked structure
which starts ~30 s before the trigger and has a total duration of ~41 s.
The emission is seen up to ~5 MeV.

As observed by Konus-Wind, the burst
had a fluence of 3.63(-0.29,+0.69)x10^-5 erg/cm2,
and a 64-ms peak energy flux, measured from T0+2.064 s,
of 6.01(-1.60,+1.62)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

Only the brightest part of the burst is covered by the
KW triggered mode data and, therefore, available for
the multi-channel spectral analysis. The time-averaged
spectrum measured from T0 to T0+8.448 s
is best fit in the 20 keV - 5 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -0.65(-0.11,+0.12),
and Ep = 663(-69,+82) keV (chi2 = 77/73 dof).
Fitting by the GRB (Band) function yields the same alpha and Ep,
and an upper limit on the high energy photon index:
beta < -3.0 (chi2 = 77/72 dof).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB150724_T67574/

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


GRB_name: GRB150724B
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18075
SUBJECT: GRB 150724B: Swift/UVOT Detection
DATE:    15/07/27 17:25:04 GMT
FROM:    Paul Kuin at MSSL  <npkuin@gmail.com>

N.P.M. Kuin(MSSL/UCL) reports on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150724B
88.6ks after the LAT trigger (Bissaldi et al., GCN Circ. 18065),
which was also observed at high energy by Fermi-GBM (Veres et al.,
GCN Circ 18066) and Konus-Wind (Golenetskii et al. GCN Circ. 18074).
Five UVOT exposures were obtained of which the first two show a
weak detection at the XRT position (Osborne et al., GCN Circ. 18069).

Preliminary magnitudes and 3-sigma upper limits using the UVOT
photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373)
are:

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

white            88619      88799          178        19.64+-0.12
white            88802      90608         1765        20.99+-0.14
white            90614      90748           60        >19.53
white            94379      94558          176        >20.82
white            94562      96236         1648        >22.01

The brightness is consistent with the RATIR observation at 147ks
in r and i (Butler et al, GCN 18072).

The magnitudes in the table 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).


GRB_name: GRB150727A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18076
SUBJECT: GRB 150727A: Swift detection of a burst with an optical counterpart
DATE:    15/07/27 19:24:14 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

S. B. Cenko (GSFC), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),
J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA),
F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester),
D. M. Palmer (LANL), J. L. Racusin (NASA/GSFC) and M. H. Siegel (PSU)
report on behalf of the Swift Team:

At 19:02:02 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 150727A (trigger=650530).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 203.990, -18.355, which is 
   RA(J2000)  =  13h 35m 58s
   Dec(J2000) = -18d 21' 16"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a large FRED-like peak
structure with a duration of about 60 sec.  The peak count rate
was ~2795 counts/sec (15-350 keV), at ~4 sec after the trigger. 

The XRT began observing the field at 19:03:19.5 UT, 77.2 seconds after
the BAT trigger. XRT found a bright, fading, uncatalogued X-ray source located
at RA, Dec 203.9705, -18.3259 which is equivalent to:
   RA(J2000)  = +13h 35m 52.92s
   Dec(J2000) = -18d 19' 33.2"
with an uncertainty of 4.7 arcseconds (radius, 90% containment). This
location is 124 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 8.93e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 86 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 13:35:52.52 = 203.96883
  DEC(J2000) = -18:19:31.4  = -18.32539
with a 90%-confidence error radius of about 0.62 arc sec. This position is 6.0
arc sec. from the center of the XRT error circle. The estimated magnitude is
18.31 with a 1-sigma error of about  0.15. No correction has been made for
extinction. 

Burst Advocate for this burst is S. B. Cenko (brad.cenko 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: GRB150724B
Detection_method: Fermi LAT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18077
SUBJECT: GRB 150724B: MASTER upper limit
DATE:    15/07/27 20:06:01 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

K.Ivanov, O.Gres, N.M.Budnev, S.Yazev,
Irkutsk State University

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

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias

D.Buckley, S. Potter, A.Kniazev, M.Kotze
South African Astronomical Observatory

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

V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov, A.Gabovich
Blagoveschensk Educational State University, Blagoveschensk

V.Krushinski, I.Zalozhnih
Ural Federal University, Kourovka

Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

Claudio Mallamaci, Carlos Lopez and Federico Podest
Observatorio Astronomico Felix Aguilar (OAFA)



MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in Tunka was pointed to the  GRB150724B (Bissaldi et al. GCN 
18065) 9244 sec after notice time and 78080 sec after trigger time
at 2015-07-25 16:26:57 UT.
We do not see any OT brighter than 20.3 inside Fermi LAT error box and at 
Swift XRT transient position (Osborne et al., GCN 18069).
All magnitudes are unfiltered (0.2B+0.8R) with respect to number USNO B 
stars).

The message may be cited.


GRB_name: GRB150724B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18078
SUBJECT: GRB 150724B: Continued RATIR Optical Observations
DATE:    15/07/27 21:00:53 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC), William 
H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), 
J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara 
(ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico 
Ramirez-Ruiz (UCSC), Jos A. de Diego (UNAM), Leonid Georgiev (UNAM), 
Jess Gonzlez (UNAM), Carlos Romn-Ziga (UNAM), Neil Gehrels (GSFC), 
and Harvey Moseley (GSFC) report:

We reobserved the field of the LAT GRB 150724B (Bissaldi et al., GCN 
18065) with the Reionization and Transients Infrared Camera (RATIR; 
www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio 
Astronmico Nacional on Sierra San Pedro Mrtir from 2015/07 27.24 to 
2015/07 27.47 UTC (8819.11 to 8824.45 hours after the Fermi trigger), 
obtaining a total of 4.01 hours exposure in the r and i bands.

We detect the source we previously reported (Butler et al. GCN 18072) at 
23:27:33.82 +3:49:06.8 (J2000, 0.5"). In comparison with the SDSS DR9, we 
obtain the following detections:

   r 23.50  0.19
   i 23.99  0.27

These magnitudes are in the AB system and are not corrected for Galactic 
extinction in the direction of the GRB.

A naive comparison to our observations from the previous night would 
suggest that the source has not faded in r but has faded in i. However, 
examining the images in detail, we suspect that our photometry in i from 
the first night might be influenced by a spuriously bright pixel. We 
therefore discount the apparent fading in i.

We thank the staff of the Observatorio Astronmico Nacional in San Pedro 
Mrtir.

[GCN OPS NOTE(27jul15): Per author's request, "140724A" was changed to "150724B" 
in the Subject-line.]


GRB_name: GRB150727A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18079
SUBJECT: GRB 150727A: Enhanced Swift-XRT position
DATE:    15/07/27 23:59:12 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 1662 s of XRT Photon Counting mode data and 4 UVOT
images for GRB 150727A, 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 = 203.96843, -18.32576 which is equivalent
to:

RA (J2000): 13h 35m 52.42s
Dec (J2000): -18d 19' 32.7"

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

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).

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


GRB_name: GRB150727A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18080
SUBJECT: GRB 150727A: VLT/X-shooter redshift
DATE:    15/07/28 05:14:42 GMT
FROM:    Nial Tanvir at U.Leicester  <nrt3@star.le.ac.uk>

N. R. Tanvir (U. Leicester), D. Xu (NAOC/CAS), T. Zafar (ESO), S. Covino (INAF/OABr), S. Schulze (PUC, MAS) report for a larger collaboration:

We observed the afterglow of GRB 150727A (Cenko et al. GCN 18076) with VLT/X-shooter, beginning at 2015-07-28 00:01 UT, about 5 hr after the burst.

Preliminary analysis of the spectrum reveals emission lines of Halpha, Hbeta and [OIII] 4959/5007 at a redshift of z=0.313. There is only marginal evidence of the [OII] 3727 doublet, suggesting the emission lines are coming from a dust obscured region (consistent also with a high Ha:Hb ratio). The continuum is faint with no clear absorption lines, but can be traced in the blue as far as the instrumental cut-off at about 3100A. Despite the absence of detected absorption features, it is likely that the emission lines are from the host galaxy and therefore that this redshift is also that of the GRB.


GRB_name: GRB150727A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18081
SUBJECT: GRB 150727A: Fermi GBM detection
DATE:    15/07/28 06:25:51 GMT
FROM:    George A. Younes at George Washington U  <gyounes@email.gwu.edu>

G. Younes (GWU) reports on behalf of the Fermi GBM Team:

"At 19:01:56.35 UT on July 27 2015, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 150727A (trigger 459716520/150727793), which
was also detected by Swift (Cenko et al. 2015, GCN 18076). The GBM
on-ground location, using the Fermi GBM trigger data, is consistent
with the Swift/XRT location.

The angle of the burst direction to the Fermi LAT boresight
 is 46 degrees.

The GBM light curve shows a FRED-like (fast-rise exponential-decay)
pulse with a duration (T90) of about 50s (50-300 keV). The
time-averaged spectrum from T0-4s to T0+56s is  well fit by a power
law with an exponential high-energy cutoff. The power law index is
-0.7 +/- 0.1 and the cutoff energy, parameterized as Epeak, is 149 +/-
10 keV.

The event fluence (10-1000 keV) in this time interval is
(7.9 +/- 0.3)E-06 ergs/cm^2. The 1.0-sec peak photon flux measured
starting from T0+5.0s in the 10-1000 keV band
is 2.1 +/- 0.2 ph/s/cm^2.

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


GRB_name: GRB150727A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18082
SUBJECT: GRB 150727A: Swift-XRT refined Analysis
DATE:    15/07/28 08:24:02 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

K.L. Page (U. Leicester), C. Pagani (U. Leicester), A. D'ai
(INAF-IASFPA), A. Maselli  (INAF-IASFPA), A. Melandri (INAF-OAB), J.A.
Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), A.P.
Beardmore (U. Leicester) and S.B. Cenko report on behalf of the
Swift-XRT team:

We have analysed 8.0 ks of XRT data for GRB 150727A (Cenko et al. GCN
Circ. 18076), from 68 s to 32.5 ks after the  BAT trigger. The data
comprise 523 s in Windowed Timing (WT) mode (the first 8 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Osborne et
al. (GCN Circ. 18079).

The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=1.2 (+/-0.4). At T+93.8 s the decay
steepens to an alpha of 2.72 (+0.11, -0.08). The light curve breaks
again at T+195 s to a decay with alpha=1.42 (+0.07, -0.06),  and  again
at T+3169 s s to alpha=8.0 (+0.0, -5.8),  before a final break at
T+4539 s s after which the decay index is 0.5 (+/-0.3).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.39 (+/-0.04). The
best-fitting absorption column is  2.0 (+/-1.5) x 10^20 cm^-2, at a
redshift of 0.313, in addition to the Galactic value of 9.8 x 10^20
cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed)
0.3-10 keV flux conversion factor deduced from this spectrum  is 2.7 x
10^-11 (3.9 x 10^-11) erg cm^-2 count^-1. 

A summary of the WT-mode spectrum is thus:
Galactic foreground: 9.8 x 10^20 cm^-2
Intrinsic column:    2.0 (+/-1.5) x 10^20 cm^-2 at z=0.313
Photon index:      2.39 (+/-0.04)

If the light curve continues to decay with a power-law decay index of
0.5, the count rate at T+24 hours will be 8.7 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.4 x
10^-13 (3.4 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/00650530.

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


GRB_name: GRB150727A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18083
SUBJECT: GRB 150727A: LCOGT-Cerro Tololo observations
DATE:    15/07/28 10:03:02 GMT
FROM:    Simone Dichiara at Ferrara U/Italy  <dichiara@fe.infn.it>

S. Dichiara, C. Guidorzi (U. Ferrara), C.G. Mundell (U. Bath),
S. Kobayashi (LJMU), A. Gomboc (U. Ljubljana) on behalf of
a large collaboration report:

Using a 1-m LCOGTN telescope in Cerro Tololo (Chile),
we began observing GRB 150727A (Cenko et al. GCN 18076;
Younes et al. GCN 18081) on July 28 01:23:01 UT
(~6.3 hours after the burst trigger) with r' and i' filters.

We did not detect the UVOT counterpart (Cenko et al. 2015, GCN 18076)
down to the following limit:

Mid time from  Total Exp   Filter    Magnitude
trigger (hr)   (s)
-------------------------------------------------
6.71           120x10        r'        > 18.9
6.76           120x9         i'        > 16.5
-------------------------------------------------

Values have been calibrated against nearby USNOB-1 stars
(R2 and I).


GRB_name: GRB150727A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18084
SUBJECT: GRB 150727A: Swift/UVOT Detection
DATE:    15/07/28 10:38:48 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld@ucl.ac.uk>

A. A. Breeveld (UCL-MSSL) and S. B. Cenko (GSFC) report on behalf of the 
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150727A
86 s after the BAT trigger (Cenko et al., GCN Circ. 18076).
A fading source consistent with the enhanced XRT position (Osborne et 
al. GCN Circ. 18079) is detected in the initial UVOT exposures.

The preliminary UVOT position is:
     RA  (J2000) =  13:35:52.52 = 203.96885 (deg.)
     Dec (J2000) = -18:19:31.3  = -18.32536 (deg.)
with an estimated uncertainty of 0.44 arc sec. (radius, 90% confidence).

Preliminary detections in the white, u and uvw2 filters and 3-sigma 
upper limits using the UVOT photometric system (Breeveld et al. 2011, 
AIP Conf. Proc. 1358, 373) for the early exposures are:

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

white               86          236          147         18.28 Â± 0.06
white              578          598           20         18.75 Â± 0.24
v                 4036         4236          197        >18.7
b                  554          574           19        >18.5
u                  298          548          246         18.75 Â± 0.16
m2                4241         4379          136        >19.1
w2                3831         4031          197         19.53 Â± 0.36

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening in the direction of the burst.


GRB_name: GRB150727A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18085
SUBJECT: GRB 150727A: Watcher optical upper limit
DATE:    15/07/28 10:39:46 GMT
FROM:    Antonio Martin-Carrillo at UCD,Space Science Group  <antonio.martin-carrillo@ucd.ie>

A. Martin-Carrillo (UCD), D. Murphy (UCD), L. Hanlon (UCD), M. Topinka (CTU), H. J. van Heerden (UFS), B. van Soelen (UFS) and P. J. Meintjes (UFS):

We observed the field of GRB 150727A (Cenko et al., GCN Circ. #18076) using the 40cm UCD Watcher telescope at Boyden Observatory in South Africa. 

Observations started at 19:19:55 UT, 1073 seconds after the burst trigger. A series of 60 sec images were taken in the SDSS r' filter using an Andor CCD camera. 
No afterglow candidate is detected in any of the individual images at the UVOT location. A 3sigma upper limit for a combined 180 second exposure is given below.

Start             | End              | Exposure | Filter | Magnitude
-------------------------------------------------------------------------------------------------
19:19:55 UT | 19:25:20 UT | 3x60 sec |  r'       |  >17.59 (3sigma upper limit)

The upper limit was calculated using nearby stars from the APASS catalogue.

This message can be cited in publications.


GRB_name: GRB150727A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18086
SUBJECT: GRB 150727A: Swift-BAT refined analysis
DATE:    15/07/28 12:05:52 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

M. Stamatikos (OSU), S. D. Barthelmy (GSFC), S. B. Cenko (GSFC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+963 sec from the recent telemetry downlinks,
we report further analysis of BAT GRB 150727A (trigger #650530)
(Cenko, et al., GCN Circ. 18076).  The BAT ground-calculated position is
RA, Dec = 203.968, -18.320 deg, which is 
   RA(J2000)  =  13h 35m 52.3s 
   Dec(J2000) = -18d 19' 11.4" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 68%.
 
The mask-weighted light curve shows a FRED-like peak starting at ~T-8 sec,
peaking at ~T+5 sec, and ramping down to a flat level at ~T+80 sec.
There is a second, small peak at ~T+90 sec.  The low level emission
continues (with a weak decline) out to T+870 sec when observations stop
due to an observing constraint.
T90 (15-350 keV) is 88 +- 13 sec (estimated error including systematics).
 
The time-averaged spectrum from T-8.70 to T+95.94 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.14 +- 0.07.  The fluence in the 15-150 keV band is 3.7 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+9.21 sec in the 15-150 keV band
is 1.0 +- 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/650530/BA/

[GCN OPS NOTE(29jul15): Per author's request, the typo on the uncertainty
in the T90 value was changed from 133 to 13 sec.]


GRB_name: GRB150728A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18087
SUBJECT: GRB 150728A: Swift detection of a GRB
DATE:    15/07/28 13:14:33 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

H. A. Krimm (CRESST/GSFC/USRA), S. D. Barthelmy (GSFC),
A. A. Breeveld (UCL-MSSL), D. N. Burrows (PSU), S. B. Cenko (GSFC),
P. A. Evans (U Leicester), C. Gronwall (PSU),
F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester),
P. Romano (INAF-IASFPA), T. Sakamoto (AGU),
B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf
of the Swift Team:

At 12:51:11 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 150728A (trigger=650617).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 292.288, +33.904 which is 
   RA(J2000)  =  19h 29m 09s
   Dec(J2000) = +33d 54' 14"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows two weak peaks
with a total duration of about 20 sec.  The peak count rate
was ~1000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 12:52:21.1 UT, 70.2 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 292.2269, 33.9165 which
is equivalent to:
   RA(J2000)  = 19h 28m 54.46s
   Dec(J2000) = +33d 54' 59.4"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 188 arcseconds from the BAT onboard position, outside 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.  We cannot determine whether the source is
fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 2.59
x 10^21 cm^-2 (Willingale et al. 2013). 

UVOT took a finding chart exposure of 150 seconds with the White
filter  starting 75 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  0.20. 

Burst Advocate for this burst is H. A. Krimm (hans.krimm 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: GRB150728A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18088
SUBJECT: GRB 150728A: Enhanced Swift-XRT position
DATE:    15/07/28 15:06:58 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 1020 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 150728A, 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 = 292.22873, +33.91604 which is equivalent
to:

RA (J2000): 19h 28m 54.89s
Dec (J2000): +33d 54' 57.7"

with an uncertainty of 4.0 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: GRB150727A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18089
SUBJECT: GRB 150727A: RATIR Optical Observations
DATE:    15/07/28 16:43:42 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC), William 
H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), 
J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara 
(ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico 
Ramirez-Ruiz (UCSC), Jos A. de Diego (UNAM), Leonid Georgiev (UNAM), 
Jess Gonzlez (UNAM), Carlos Romn-Ziga (UNAM), Neil Gehrels (GSFC), 
and Harvey Moseley (GSFC) report:

We observed the field of GRB 150727A (Cenko et al., GCN 18076) with the 
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 
1.5m Harold Johnson Telescope at the Observatorio Astronmico Nacional on 
Sierra San Pedro Mrtir from 2015/07 28.15 to 2015/07 28.21 UTC (8.65 to 
9.95 hours after the BAT trigger), obtaining a total of 1.07 hours 
exposure in the r, i, and z bands.

We detect a source at the edge of the Swift/XRT error circle (Osborne et 
al., GCN 18079), at RA, Dec (J2000) = 13:35:52.52, -18:19:31.4 (0.5"). In 
comparison with the USNO-B1 and 2MASS catalogs, we obtain the following 
detections and upper limits (3-sigma):

   r 21.13  0.19
   i 21.40  0.13
   z > 19.57

These magnitudes are in the AB system and are not corrected for Galactic 
extinction in the direction of the GRB.

Our detections appear to be consistent with the non-detections at 
shallower depths reported by Dichiara et al. (GCN 18083). Tanvir et al. 
(GCN 18080) report a tentative spectroscopic redshift of 0.313.

Further observations are planned.

We thank the staff of the Observatorio Astronmico Nacional in San Pedro 
Mrtir.


GRB_name: GRB150728A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18090
SUBJECT: GRB 150728A: FTN observations
DATE:    15/07/28 17:07:38 GMT
FROM:    Simone Dichiara at Ferrara U/Italy  <dichiara@fe.infn.it>

S. Dichiara, C. Guidorzi (U. Ferrara), C.G. Mundell (U. Bath),
S. Kobayashi (LJMU), A. Gomboc (U. Ljubljana) on behalf of
a large collaboration report:

The 2-m Faulkes Telescope North began observing Swift GRB 150728A
(Krimm et al. GCN 18087) on July 28, 13:48:25 UT (~57 minutes after
the BAT trigger) with SDSS r and i filters.

we identify an uncatalogued object within XRT error circle
(Beardmore et al. GCN 18088), at the following position:

RA(J2000) = 19:28:54.81
Dec(J2000)= +33:54:58.0

with an uncertainty of 1". The counterpart has the following
 magnitudes:

Mid time from  Total Exp   Filter    Magnitude
trigger (min)   (s)
-------------------------------------------------
61.8            120x5        r'     21.8 +- 0.3
73.3            120x5        i'     20.7 +- 0.3
-------------------------------------------------

Magnitudes are calibrated against nearby USNOB-1 stars
(R2 and I).
Presently we cannot state anything about possible variability in
the source flux. However, we note that field is quite crowded.


GRB_name: GRB150728A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18091
SUBJECT: GRB 150728A: Swift-BAT refined analysis
DATE:    15/07/28 17:30:34 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU)
(i.e. the Swift-BAT team):
 
Using the data set from T-240 to T+946 sec from the recent telemetry downlinks,
we report further analysis of BAT GRB 150728A (trigger #650617)
(Krimm, et al., GCN Circ. 18087).  The BAT ground-calculated position is
RA, Dec = 292.271, 33.906 deg, which is 
   RA(J2000)  =  19h 29m 05.1s 
   Dec(J2000) = +33d 54' 20.8" 
with an uncertainty of 2.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.
 
The mask-weighted light curve shows a single spike starting at ~T_zero
and ending at ~T+1.5 sec.  T90 (15-350 keV) is 0.83 +- 0.23 sec
(estimated error including systematics).
 
The time-averaged spectrum from T+0.24 to T+1.20 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.02 +- 0.48.  The fluence in the 15-150 keV band is 3.3 +- 1.0 x 10^-8 erg/cm2.
The 1-sec peak photon flux measured from T+0.22 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/650617/BA/


GRB_name: GRB150728A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18092
SUBJECT: GRB 150728A: Swift/UVOT Upper Limits
DATE:    15/07/28 21:08:25 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld@ucl.ac.uk>

A. A. Breeveld (UCL-MSSL) and H. A. Krimm (CRESST/GSFC/USRA) report on 
behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150728A 75 
s after the BAT trigger (Krimm et al., GCN Circ. 18087).
No optical afterglow consistent with the XRT position (Beardmore et al. 
GCN Circ. 18088) or the Faulkes position (Dichiara et al. GCN Circ. 
18090) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system 
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding 
chart (FC) exposure and subsequent exposures are:

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

white_FC            75          225          147         >21.3
u_FC               288          537          246         >20.4
white               75         6991          730         >22.0
v                  617         5982          275         >19.8
b                  543         6803          452         >21.1
u                  288         6597          678         >21.0
w1                 668         6392          452         >20.4
m2                 643         6187          452         >20.2
w2                 593         5777          255         >20.1

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening of E(B-V) = 0.20 in the direction of the 
burst (Schlegel et al. 1998).


GRB_name: GRB150728A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18093
SUBJECT: GRB 150728A: Swift-XRT refined Analysis
DATE:    15/07/29 01:14:03 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

C. Pagani (U. Leicester), A. Maselli  (INAF-IASFPA), A. Melandri
(INAF-OAB), P. D'Avanzo (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), D.N.
Burrows (PSU), T.G.R. Roegiers (PSU), A.P. Beardmore (U. Leicester),
P.A. Evans (U. Leicester) and H.A. Krimm report on behalf of the
Swift-XRT team:

We have analysed 6.7 ks of XRT data for GRB 150728A (Krimm et al. GCN
Circ. 18087), from 79 s to 30.0 ks after the  BAT trigger. The data are
entirely in Photon Counting (PC) mode. The enhanced XRT position for
this burst was given by Beardmore et al. (GCN Circ. 18088). The source
is fading with alpha >0.4.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00650617.

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


GRB_name: GRB150728A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18094
SUBJECT: GRB 150728A: AAO optical observations
DATE:    15/07/29 18:30:31 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI), R. Inasaridze (AAO), Sh. Makandarashvili (AAO),   A.
Volnova (IKI), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of 
larger GRB follow-up collaboration:

We observed the field of the Swift GRB 150728A (Krimm et al. GCN 18087) 
  with AS-32 (0.7m) telescope of Abastumani Observatory starting on Jul. 
28 (UT) 19:32:14.  Within the enhanced XRT error circle (Beardmore et 
al. GCN 18088) we detected the object coinciding with the object found 
by FTN (Dichiara et al. GCN 18090).  A photometry of the object is following

Date       UT start    t-T0     Filter  Exp.     OT
                        (mid, days)      (s)

2015-07-28 19:32:14    0.30491  None    28*120   20.6+/-0.25

The photometry is based on nearby USNO-B1.0 stars
USNO-B.1_id  R2
1239-0338943 17.06
1239-0338998 16.69

The photometry could be biased by nearby star. Presently we cannot say 
nothing about variability of the object and more observation is 
necessary to confirm/reject the object as afterglow of GRB 150728A.


GRB_name: GRB150727A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18095
SUBJECT: GRB 150727A: Continued RATIR Optical Observations - Fading
DATE:    15/07/29 20:03:54 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC),
William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori
Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino
Cucchiara (ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU),
Enrico Ramirez-Ruiz (UCSC), Jos A. de Diego (UNAM), Leonid Georgiev
(UNAM), Jess Gonzlez (UNAM), Carlos Romn-Ziga (UNAM), Neil Gehrels
(GSFC), and Harvey Moseley (GSFC) report:

We observed the field of GRB 150727A (Cenko et al., GCN 18076) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on
the 1.5m Harold Johnson Telescope at the Observatorio Astronmico
Nacional on Sierra San Pedro Mrtir from 2015/07 29.15 to 2015/07 29.19
UTC (32.64 to 33.50 hours after the BAT trigger), obtaining a total of
0.70 hours exposure in the r, i, and z bands.

We no longer detect the source seen on the previous night (Watson et
al., GCN 18089). In comparison with the USNO-B1 and 2MASS catalogs, we
obtain the following upper limits (3-sigma):

   r > 22.27
   i > 22.61
   z > 19.11

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.

The source has faded by at least 1 magnitude in both r and i. We
therefore suggest that it it corresponds to the afterglow.

We thank the staff of the Observatorio Astronmico Nacional in San Pedro
Mrtir.


GRB_name: GRB150728A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18096
SUBJECT: GRB 150728A: RATIR Optical Observations
DATE:    15/07/29 20:07:03 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC), William 
H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), 
J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara 
(ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico 
Ramirez-Ruiz (UCSC), Jos A. de Diego (UNAM), Leonid Georgiev (UNAM), 
Jess Gonzlez (UNAM), Carlos Romn-Ziga (UNAM), Neil Gehrels (GSFC), 
and Harvey Moseley (GSFC) report:

We observed the field of GRB 150728A (Krimm et al., GCN 18087) with the 
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 
1.5m Harold Johnson Telescope at the Observatorio Astronmico Nacional on 
Sierra San Pedro Mrtir from 2015/07 29.19 to 2015/07 29.48 UTC (15.73 to 
22.75 hours after the BAT trigger), obtaining a total of 5.29 hours 
exposure in the r, i, and z bands.

The brightest source within the enhanced Swift/XRT error circle (Beardmore 
et al., GCN 18088) is the cataloged source 2MASS 19285425+3354576, for 
which we determine a position of 19:28:54.26 +33:54:57.6 (J2000, 0.5") 
and magnitudes:

   r 16.71  0.02
   i 16.49  0.01
   z 16.14  0.04

We detect two other uncataloged sources on the edge of the error circle. 
For source A we determine a position of 19:28:54.80 +33:54:58.2 (J2000, 
0.5") and magnitudes:

   r     21.37  0.04
   i     20.89  0.04
   z     19.54  0.13

and for source B we determine 19:28:54.25 +33:55:2.6 (J2000, 0.5") and:

   r     21.11  0.04
   i     20.73  0.03
   z     20.21  0.21

These magnitudes are in comparison with the USNO-B1 and 2MASS catalogs, 
are in the AB system, and are not corrected for Galactic extinction in the 
direction of the GRB.

Our source A appears to correspond to the source reported by Dichiara et 
al. (GCN 18090). If this association is correct, then there is little 
evidence for fading between about 1 hour and 16-23 hours.

We thank the staff of the Observatorio Astronmico Nacional in San Pedro 
Mrtir.


GRB_name: GRB150728A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18097
SUBJECT: GRB 150728A: TSHAO optical observations
DATE:    15/07/30 18:41:10 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI), I. Reva (Fesenkov Astrophysical Institute),   A. 
Volnova (IKI), A. Pozanenko  (IKI) report on behalf of larger GRB 
follow-up collaboration:

We observed the field of the Swift GRB 150728A (Krimm et al. GCN 18087) 
   with Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical 
Observatory starting on Jul. 29 (UT) 18:34:50.  We obtained several 
images in R-filter.  In a combined image we do not detect the FTN object 
(Dichiara et al. GCN 18090) also visible in AAO observations (Mazaeva et 
al., GCN 18094) and source A in RATIR observations (Watson  et al., GCN 
18096).
A photometry of the field is following

Date       UT start    t-T0     Filter  Exp.     ULimit (3sigma)
                        (mid, days)      (s)

2015-07-29 18:34:50    1.26425  R       15*300   21.2

The photometry is based on nearby USNO-B1.0 stars
USNO-B.1_id  R2
1239-0338943 17.06
1239-0338998 16.69

Also we marginally detect object B of the  RATIR observations (Watson 
et al., GCN 18096) in our current and previous observation of the field 
(Mazaeva et al., GCN 18094).

The finding chart can be found in 
http://grb.rssi.ru/GRB150728A/GRB150728A_AAO_left_TSHAO_right.png

Would the source A be a  non-variable point like object with magnitudes 
of  r=21.37+/-0.04 and   i=20.89+/-0.04 (Watson  et al., GCN 18096) in 
our observation the object A might be detected  as the object with a 
magnitude less than R=21.3 (3 sigma). So we tentatively suggest the 
object A as an afterglow candidate.


GRB_name: GRB150728A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18098
SUBJECT: GRB 150728A: Continued RATIR Optical Observations
DATE:    15/07/31 17:52:51 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC), William 
H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), 
J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara 
(ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico 
Ramirez-Ruiz (UCSC), Jos A. de Diego (UNAM), Leonid Georgiev (UNAM), 
Jess Gonzlez (UNAM), Carlos Romn-Ziga (UNAM), Neil Gehrels (GSFC), 
and Harvey Moseley (GSFC) report:

We observed the field of GRB 150728A (Krimm et al., GCN 18087) with the 
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 
1.5m Harold Johnson Telescope at the Observatorio Astronmico Nacional on 
Sierra San Pedro Mrtir from 2015/07 31.22 to 2015/07 31.46 UTC (64.53 to 
70.24 hours after the BAT trigger), obtaining a total of 3.60 hours 
exposure in the r, i, and z bands.

For source A of Watson et al. (GCN 18096), we determine:

   r 21.26  0.04
   i 20.90  0.04
   z 19.43  0.13

For source B of Watson et al. (GCN 18096), we determine:

   r 20.91  0.04
   i 20.70  0.04
   z 20.48  0.31

These magnitudes are in comparison with the USNO-B1 and 2MASS catalogs, 
are in the AB system, and are not corrected for Galactic extinction in the 
direction of the GRB.

Our source A appears to correspond to the source reported by Dichiara et 
al. (GCN 18090). If this association is correct, then there is little 
evidence for fading between observations at about 1 hour, 16-23 hours, and 
65-70 hours. This is in contrast to the suggestion of Mazaeva et al. (GCN 
18097), who suggested that source A might indeed be the fading afterglow 
on the basis of a 3-sigma non-detection at 30 hours.

Similarly, there is little evidence for fading of source B between 16-23 
hours and 65-70 hours.

We thank the staff of the Observatorio Astronmico Nacional in San Pedro 
Mrtir.


GRB_name: GRB150724B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18099
SUBJECT: GRB150724B: Retraction of the uvot detection
DATE:    15/07/31 21:00:42 GMT
FROM:    Paul Kuin at MSSL  <npkuin@gmail.com>

Paul Kuin (MSSL/UCL) reports on behalf of the Swift/UVOT
team:

In GCN Circ.18075 we reported a detection in the first two
white band images with the Swift UVOT.

Further examination of the UVOT data showed that in the
initial analysis the background region included part off
the detector and gave a false reading. Correcting for that
it is found that for the first two images there is just an
upper limit of  white > 22.00 mag at 88.7ks after the
trigger.

We apologise for the confusion this error may have caused.


GRB_name: GRB150424A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18100
SUBJECT: GRB 150424A: HST imaging
DATE:    15/07/31 21:13:57 GMT
FROM:    Nial Tanvir at U.Leicester  <nrt3@star.le.ac.uk>

N. R. Tanvir (U. Leicester), A. J. Levan (U. Warwick), A. S. Fruchter (STScI), J. Hjorth, D. Watson (DARK), D. Perley (Caltech), J. Greiner (MPE), A. de Ugarte Postigo, C. Thoene (IAA-CSIC), R. A. Hounsell (Illinois), S. Rosswog (U. Stockholm) report:

We observed the optical/nIR counterpart of short-GRB 150424A (Perley et al. GCN 17745) with HST at three epochs, roughly 6.7, 9.3 and 13.9 days post-trigger. On each occasion we obtained imaging with the WFC3/UVIS F606W and the WFC3/IR F125W and F160W filters.

The optical transient is visible at all epochs, fading from J(AB)=25.3 to J(AB)=26.9 over the course of the observations. There is a suggestion of a colour change, from r-H(AB)~1.1 to r-H(AB)~2 between the first and last epoch, although the errors are large (and in particular suffer a rather uncertain background correction - see below).

Significantly, the OT is superimposed on a faint source that is extended over about 1 arcsec. We propose that this extended source is most likely the host galaxy of the burst, rather than the bright nearby spiral whose redshift (z=0.3) was reported by Castro-Tirado et al. (GCN 17758). Our current best estimates of the magnitude of this source are r(AB)=26.8, J(AB)=26.1 and H(AB)=25.7, although we note that much of the flux in the r-band is due to a single blue knot of emission, whereas the nIR is more diffuse. Given the luminosity, size and colour of the proposed host, it is likely to be at z>0.7, where the 4000A break would help explain the red r-J colour of most of this galaxy.

If the burst was at z=0.3 (e.g. if the faint extended source is a satellite of the spiral, or just a background galaxy aligned by chance), then we place limits on any kilonova/macronova emission of M_J(AB)>~-14.7 at 7 days post-burst in the rest frame.  A more likely redshift of z~1, for example, would mean that our reddest filter only corresponds to the rest-frame I-band, here providing a limit of M_I(AB)>~-17.0 at 7 days in the rest-frame (i.e. ~1 mag fainter than typical for a collapsar-produced supernova at the same time).

Further analysis is in progress.


GRB_name: GRB150724B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18101
SUBJECT: GRB 150724B: Swift-XRT afterglow detection
DATE:    15/08/01 05:05:00 GMT
FROM:    Kim Page at U.of Leicester  <kpa@star.le.ac.uk>

J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U.
Leicester), V. D'Elia (ASDC), A. D'ai (INAF-IASFPA), A. Maselli 
(INAF-IASFPA), L.M. McCauley (PSU), J.A. Kennea (PSU), B. Sbarufatti
(INAF-OAB/PSU) and P.A. Evans (U. Leicester) report on behalf of the
Swift-XRT team:

Swift-XRT has conducted further observations of the field of the
Fermi/LAT-detected burst GRB 150724B (Bissaldi et al. GCN Circ. 18065).
The observations now extend from T0+88.6 ks to T0+607.8 ks. The source
previously reported by Osborne et al. (GCN Circ. 18069), "Source 1", is
fading with 3-sigma significance, and is therefore likely the GRB
afterglow.  The position of this source is RA, Dec=351.8905, +3.8181
which is equivalent to:

RA (J2000): 23:27:33.71
Dec(J2000): +03:49:05.2

with an uncertainty of 4.1 arcsec (radius, 90% confidence).  This
position is 9.1 arcmin from the Fermi/LAT position.  The source is
fading with alpha >0.3.

The results of the XRT-team automatic analysis of the likely afterglow
are at http://www.swift.ac.uk/ToO_GRBs/00020543/index_1.php.
The results of the full analysis of the XRT observations are available
at http://www.swift.ac.uk/ToO_GRBs/00020543.

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


GRB_name: GRB150801A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  18102
SUBJECT: GRB 150801A: MAXI/GSC detection
DATE:    15/08/01 13:23:23 GMT
FROM:    H. Negoro at Nihon U.  <negoro@phys.cst.nihon-u.ac.jp>

M. Ishikawa, S. Nakahira (JAXA), H. Negoro, (Nihon U.), 
S. Ueno, H. Tomida,  M. Kimura, Y. E. Nakagawa (JAXA),
T. Mihara, M. Sugizaki, M. Serino, M. Shidatsu, J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN), 
N. Kawai, Y. Tachibana, T. Yoshii (Tokyo Tech), 
A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU), 
H. Tsunemi, R. Imatani (Osaka U.), M. Nakajima, T. Masumitsu, K. Tanaka (Nihon U.), 
Y. Ueda, T. Kawamuro, T. Hori (Kyoto U.), Y. Tsuboi, S. Kanetou (Chuo U.), 
M. Yamauchi, D. Itoh (Miyazaki U.), K. Yamaoka (Nagoya U.), M. Morii (ISM) 
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient 
source at 01:18:55 UT.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (256.013 deg, -9.523 deg) = (17 04 03, -09 31 22) (J2000) 
with a statistical 90% C.L. elliptical error region 
with long and short radii of 0.26 deg and 0.25 deg, respectively. The roll
angle of long axis from the north direction is 50.0 deg counterclockwise. 
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).

Without assumptions on the source constancy, we obtain a rectangular error
box for the transient source with the following corners:
(R.A., Dec) = (255.708 deg, -10.291 deg) = (17 02 49, -10 17 28) (J2000)
(R.A., Dec) = (255.273 deg, -9.991 deg) = (17 01 05, -09 59 28) (J2000)
(R.A., Dec) = (256.932 deg, -8.065 deg) = (17 07 43, -08 03 53) (J2000)
(R.A., Dec) = (257.356 deg, -8.376 deg) = (17 09 25, -08 22 32) (J2000)

The X-ray flux averaged over the scan was 103 +- 21 mCrab
(4-10keV, 1 sigma error).
There was no significant excess flux in the previous transit at 23:46 UT on 31 July
and in the next transit at 02:51 UT with an upper limit of 20 mCrab for each.


