# GCN_circulars

GRB_name: GRB160712A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19702
SUBJECT: GRB 160712A: Further GROND observations
DATE:    16/07/14 09:11:44 GMT
FROM:    Thomas Kruehler at MPE Garching  <kruehler@mpe.mpg.de>

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

We re-observed the field of GRB 160712A (Swift trigger 704155; Hagen et
al., GCN #19684) simultaneously in g'r'i'z'JHK with GROND (Greiner
et al. 2008, PASP 120, 405) mounted at the 2.2m MPG telescope at the
ESO La Silla Observatory (Chile).

Observations started at 04:38:43 UT on 2016-07-14, 32.8 hr after the GRB
trigger, and consisted of multiple exposures with a total integration
time of around 80 minutes. The average seeing and airmass were 2â€.0 and
1.0, respectively.

Within photometric errors, no variability is detected with respect to
our earlier observations (GCN 19693, see also Troja et al. GCN 19695).
The source is hence unlikely to be the afterglow of GRB 160712A.


GRB_name: GRB160714A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19703
SUBJECT: GRB 160714A: MASTER early optical observations
DATE:    16/07/14 09:16:52 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

A.Kuznetsov, V. Lipunov,  E.S.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

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

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

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

Ricardo Podesta, Carlos Lopez and Federico Podest
Observatorio Astronomico Felix Aguilar (OAFA)

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

MASTER-IAC  robotic telescope (MASTER-Net: http://observ.pereplet.ru, 4 
square degrees twin telescope) 
located in IAC was pointed to the  GRB160714A (Siegel et al., GCN 19697) 
26 sec after notice time and 50 sec after trigger time at 2016-07-14
02:20:05 UT. On our first (10s exposure)  set we not  found optical
transient within SWIFT error-box (ra=15 37 50 dec=+63 49 51 r=0.05 degrees)
brighter then 16.1.

Our automatic results of the first 20 minutes observations after trigger 
tieme are:

   Id  Pro.type    Time UT       Exp.time Limit Filt.   Tube
                                     s

269575     Alert    02:20:05         10          16.1     P|    EAST
269574     Alert    02:20:05         10          16.4     P-    WEST
269582  SumAlert    02:20:05         60          17.7     P|    EAST
269585  SumAlert    02:20:05         60          17.9     P-    WEST
269639  SumAlert    02:20:05        700          19.6     P|    EAST
269626  SumAlert    02:20:05        700          19.9     P-    WEST
269577     Alert    02:20:47         20          17.3     P|    EAST
269576     Alert    02:20:47         20          17.3     P-    WEST
269579    Alert    02:21:21      30          17.5   P| EAST
269578    Alert    02:21:21      30          17.8     P- WEST
269581    Alert    02:22:05      30          17.5   P| EAST
269580     Alert    02:22:05         30          17.6     P-    WEST
269588  SumAlert    02:22:05        120          18.6     P|    EAST
269591 SumAlert    02:22:05     120          18.6   P- WEST
269584    Alert    02:22:49      40          17.8   P| EAST
269583    Alert    02:22:49      40          17.9   P- WEST
269587    Alert    02:23:41      50          17.9   P| EAST 
269586    Alert    02:23:41         50          17.9   P- WEST 
269590    Alert    02:24:46      70          18.2     P| EAST
269589     Alert    02:24:46         70          18.2     P-    WEST
269597  SumAlert    02:24:46        250          19.1     P|    EAST
269596  SumAlert    02:24:46        250          19.4     P-    WEST
269592     Alert    02:26:11         80          18.2     P|    EAST
269593     Alert    02:26:11         80          18.5     P-    WEST
269595    Alert    02:27:45     100          18.5   P| EAST
269594    Alert    02:27:45     100          18.6   P- WEST
269599    Alert    02:29:38     120          18.5   P| EAST
269598    Alert    02:29:38     120          18.6   P- WEST
269601    Alert    02:31:51     150          18.6   P| EAST
269600    Alert    02:31:51     150          18.9   P- WEST
269603    Alert    02:34:34     180          18.5   P| EAST
269602    Alert    02:34:34        180          18.6   P- WEST
269665  SumAlert    02:34:34       1800          19.6     P|    EAST
269675 SumAlert    02:34:34    1800          19.5   P- WEST
269604    Alert    02:38:06     180          18.5   P| EAST
269605     Alert    02:38:06        180          18.6     P-    WEST
269610  SumAlert    02:38:06        540          19.2     P|    EAST
269613 SumAlert    02:38:06     540          19.2   P- WEST
269606    Alert    02:41:33     180          18.5   P| EAST
269607    Alert    02:41:33     180          18.6   P- WEST

The message may be cited.


GRB_name: GRB160714A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19705
SUBJECT: GRB 160714A: Swift-BAT refined analysis,
DATE:    16/07/14 14:10:23 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

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), D. M. Palmer (LANL), T. Sakamoto (AGU),
M. H. Siegel (PSU), 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 160714A (trigger #704310)
(Siegel, et al., GCN Circ. 19697).  The BAT ground-calculated position is
RA, Dec = 234.490, 63.809 deg which is
   RA(J2000)  =  15h 37m 57.7s
   Dec(J2000) = +63d 48' 32.1"
with an uncertainty of 2.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 35%.
 
The mask-weighted light curve shows a double-peak structure starting at
T0, peaking at T+0.05 sec and T+0.2 sec and ending at T+0.3 sec.
T90 (15-350 keV) is 0.35 +- 0.11 sec (estimated error including systematics).
 
The time-averaged spectrum from T+0.02 to T+0.40 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.38 +- 0.37.  The fluence in the 15-150 keV band is 6.9 +- 1.6 x 10^-8 erg/cm2.
The 1-sec peak photon flux measured from T-0.29 sec in the 15-150 keV band
is 1.1 +- 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/704310/BA/


GRB_name: GRB160623A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19708
SUBJECT: GRB 160623A: optical astrometry, photometry, and redshift
DATE:    16/07/14 16:46:12 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>

D. Malesani (DARK/NBI), A. de Ugarte Postigo (IAA-CSIC and DARK/NBI), M. 
De Pasquale (UCL/MSSL), D. A. Kann (TLS Tautenburg), Z. Cano (Univ. 
Iceland), D. A. Perley (DARK/NBI), L. Izzo (IAA-CSIC), C. C. Thoene 
(IAA-CSIC),

N. Butler (ASU), A. M. Watson (UNAM), A. Kutyrev (GSFC), W. H. Lee 
(UNAM), M. G. Richer (UNAM), O. Fox (STScI), J. X. Prochaska (UCSC), J. 
S. Bloom (UCB), A. Cucchiara (GSFC/STScI), E. Troja (GSFC), O. 
Littlejohns (ASU), E. Ramirez-Ruiz (UCSC), J. A. de Diego (UNAM), L. 
Georgiev (UNAM), J. Gonzalez (UNAM), C. Roman-Zuniga (UNAM), N. Gehrels 
(GSFC), H. Moseley (GSFC), J. Capone (UMD), V. Zach Golkhou (ASU), and 
V. Toy (UMD), on behalf of the RATIR collaboration,

report:

We observed the field of GRB 160623A (Vianello et al., GCN 19553; 
Frederiks et al., GCN 19554; Mailyan et al., GCN 19555) with the Nordic 
Optical Telescope (NOT) equipped with the AlFOSC imager. Our 
observations had a mid time 2016 July 8.09 UT (14.88 days after the GRB 
trigger) and consisted of 6x300 s in the SDSS i filter.

Close to the position of the optical and X-ray afterglow (Mingo et al., 
GCN 19558; Pozanenko et al., GCN 19561; Butler et al., GCN 19567), we 
detect a bright source at the following coordinates (J2000):

RA = 21:01:11.65
Dec = +42:13:15.0

We measure I = 20.6 +- 0.2 (Vega) against several nearby USNO stars 
(error dominated by the calibration). To determine the relation of this 
object with the GRB afterglow, we cross-registered our image with those 
from RATIR (Butler et al., GCN 19567), yielding an RMS of 0.02". We find 
that the NOT source is offset to the SE of the afterglow by 0.7". This 
source could thus be the host galaxy or an unrelated, foreground star. 
We also note some faint emission in the RATIR image at the NOT 
coordinates, despite being blended with the brighter afterglow.

A picture showing the comparison of the two images is shown here:

http://www.astro.ku.dk/~malesani/GRB/160623A/GRB160623A_NOT_RATIR.png

A spectrum (3x1200 s exposure) was acquired using the Gran Telescopio 
Canarias (GTC) equipped with OSIRIS, covering the wavelength range 
5100-10,000 AA (grism R1000R), starting on 2016 July 10.163 UT (16.95 
days after the GRB). The slit was centered at the coordinates of the NOT 
object, but also partially overlapped with the afterglow location.

We detect continuum over the whole wavelength range and two emission 
lines in the red part of the spectrum, which we interpret as Halpha and 
[N II] at a common redshift z = 0.367. At the same redshift we also 
detect weak [O III] 5008 (dimmed by the large foreground extinction). 
This is most likely the redshift of GRB 160623A.

The source detected in the NOT image is possibly a foreground star (the 
Galactic latitude is b = -2.7 deg). In the GTC acquisition image, the 
object is pointlike with a seeing of 1.2". On the other hand, inspecting 
the 2D spectrum, the spatial profile of the emission lines is different 
from that of the continuum: the features are wider and elongated towards 
the position of the afterglow. A compact host cannot however be excluded.

At z = 0.367, a SN as bright as SN 1998bw would only reach a peak 
magnitude of I ~ 24.8 (Vega) given the large Galactic extinction (A_I = 
2.2 mag; Schlafly & Finkbeiner 2011). From ground, such a SN would be 
difficult to distinguish against the brighter foreground object.

We acknowledge excellent support from the observers at the NOT (in 
particular Roi Alonso and Diego Hidalgo) and at the GTC.


GRB_name: GRB160714A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19709
SUBJECT: GRB 160714A: Fermi GBM observation
DATE:    16/07/14 17:04:04 GMT
FROM:    Hoi-Fung Yu at MPE  <sptfung@mpe.mpg.de>

Hoi-Fung Yu (MPE) and Charles A. Meegan (USRA)
report on behalf of the Fermi GBM Team:

"At 02:19:15.62 UT on 14 July 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160714A (trigger 490155559/160714097),
which was also detected by the Swift/BAT (Siegel et al. 2016, GCN 19697)
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 51 degrees.

The GBM light curve shows a short pulse with sub-structures
with a duration (T90) of about 0.32 s (50-300 keV).
The time-averaged spectrum from T0-0.064 s to T0+0.192 s is
best fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.5 +/- 0.4 and
the cutoff energy, parameterized as Epeak, is 200 +/- 55 keV.

The event fluence (10-1000 keV) in this time interval is
(1.6 +/- 0.3)E-07 erg/cm^2. The 64-ms peak photon flux measured
starting from T0+0.128 s in the 10-1000 keV band is 6 +/- 1 ph/s/cm^2.

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


GRB_name: GRB160623A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19710
SUBJECT: GRB 160623A: afterglow spectroscopy by GTC and independent redshift determination
DATE:    16/07/14 18:44:42 GMT
FROM:    Alberto Castro-Tirado at Inst.de Astro. de Andalucia  <ajct@iaa.es>

A. J. Castro-Tirado (IAA-CSIC), A. F. Valeev (SAO-RAS), S. Jeong (SKKU), 
R. SÃ¡nchez-RamÃ­rez (IAA-CSIC), V. V. Sokolov (SAO-RAS), P. Ferrero 
(IAA-CSIC), J. C. Tello (IAA-CSIC), Y. Hu (IAA-CSIC), B.-B. Zhang 
(IAA-CSIC), A. Pozanenko (IKI-RAS), S. R. Oates (U. of Warwick), S. 
Geier (GTC) and G. Lombardi (GTC), on behalf of a larger collaboration, 
report:

Following the detection of GRB 160623A by Fermi (Vianello et al. GCNC 
19553) and Konus-Wind (Frederiks et al. GCNC 19554), we observed the 
optical afterglow of GRB 160623A (Pozanenko et al. GCNC 19561) with the 
10.4m Gran Telescopio Canarias (GTC), gathering spectra at different 
epochs: June 25 (1.9 days post-burst) and July 3/4, with both the R1000B 
and R2500I grisms covering the range 3800-10000 A. At the position of 
the afterglow, the reddest spectrum (2 x 1200s with R2500I) showed 
H-alpha and [SII] in emission, from which we determine a redshift z = 
0.367, confirming the value proposed by Malesani et al. (GCNC 19708). 
The bluest range spectrum (1200s) also revealed a marginal detection of 
H-beta (taking into account the high foreground Galactic extinction in 
the line of sight). The faint continuum on the first epoch spectrum 
extended down to 3800 A with no absorption lines being present. 
Therefore we propose this is the redshift of the GRB 160623A host 
galaxy.

We acknowledge excellent support from the GTC staff.


GRB_name: GRB160714A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19711
SUBJECT: GRB 160714A: Swift-XRT observations
DATE:    16/07/14 20:31:37 GMT
FROM:    Boris Sbarufatti at INAF-OAB/IASFPA  <boris.sbarufatti@brera.inaf.it>

J.P. Osborne (U. Leicester), K.L. Page (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), B.
Mingo (U. Leicester) and D. M. Palmer (LANL) report on behalf of the
Swift-XRT team:

We have analysed 6.2 ks of Photon Counting (PC) mode XRT data for the
Swift/BAT-detected burst GRB 160714A (Palmer et al. GCN Circ. 19705),
collected between T0+1.7 ks and T0+43.3 ks. 

Three uncatalogued X-ray sources have been detected within 296 arcsec
of the Swift/BAT position, 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):  234.3249  =  15:37:17.98
  Dec (J2000): +63.8684  =  +63:52:06.3
  Error: 4.3 arcsec (radius, 90% conf.)
  Count-rate: (5.8 +/- 1.2)e-3 ct s^-1  
  Distance: 254 arcsec from Swift/BAT position.
  Flux: (1.78 +/- 0.37)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 4:
  RA (J2000):  234.5768  =  15:38:18.43
  Dec (J2000): +63.7722  =  +63:46:19.8
  Error: 4.8 arcsec (radius, 90% conf.)
  Count-rate: (3.07 +/- 0.95)e-3 ct s^-1   
  Distance: 280 arcsec from Swift/BAT position.
  Flux: (8.3 +/- 2.6)e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 9:
  RA (J2000):  234.4312  =  15:37:43.50
  Dec (J2000): +63.8530  =  +63:51:10.9
  Error: 7.1 arcsec (radius, 90% conf.)
  Count-rate: (1.70 +/- 0.76)e-3 ct s^-1   
  Distance: 92 arcsec from Swift/BAT position.
  Flux: (7.0 +/- 3.2)e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Eight uncatalogued sources were also 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/00704310.

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


GRB_name: GRB160714A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19712
SUBJECT: GRB 160714A: TAROT Calern observatory optical observations
DATE:    16/07/14 21:00:38 GMT
FROM:    Alain Klotz at IRAP-CNRS-OMP  <Alain.Klotz@free.fr>

Klotz A., Turpin D., Atteia J.L. (CNRS-OMP-IRAP),
Boer, M., Laugier, R. (CNRS-ARTEMIS),
Gendre B. (UVI - Etelman Obs.) report:

We imaged the field of GRB 160714A detected by SWIFT
(trigger 704310) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.

The observations started 40s after the GRB trigger
(20s after the notice). The elevation of the field decreased from
34 degrees above horizon and weather conditions
were good.

The first image is trailed with a duration of 60.0s
(see the description in Klotz et al., 2006, A&A 451, L39).
We do not detect any OT with a limiting magnitude of:
t0+40.0s to t0+100.0s : Rlim = 16.3

The second image is 30.0s exposure in tracking mode:
t0+115.7s to t0+145.7s : Rlim = 17.5

We co-added a series of exposures:
t0+115.7s to t0+412.9s : Rlim = 18.9

Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.


GRB_name: GRB160712A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19713
SUBJECT: GRB 160712A: Swift-BAT refined analysis
DATE:    16/07/14 21:15:57 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

M. Stamatikos (OSU), 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),
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 160712A (trigger #704155)
(Hagen, et al., GCN Circ. 19684).  The BAT ground-calculated position is
RA, Dec = 304.166, -26.965 deg which is
  RA(J2000)  =  20h 16m 39.9s
  Dec(J2000) = -26d 57' 52.8"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 24%.

The mask-weighted lightcurve shows the burst starting at ~T-5 sec, with a spike
at ~T0 sec, extending past T+95 sec where the data ends when the burst position
moves out of the BAT FOV due to a slew.

The time-averaged spectrum from T-8.60 to T+45.46 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.18 +- 0.13.  The fluence in the 15-150 keV band is 2.6 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+0.06 sec in the 15-150 keV band
is 2.4 +- 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/704155/BA/


GRB_name: GRB160716A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19716
SUBJECT: GRB 160716A: Swift detection of a burst
DATE:    16/07/16 01:20:39 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

L. M. Z. Hagen (PSU), S. D. Barthelmy (GSFC), J. A. Kennea (PSU) and
D. M. Palmer (LANL) report on behalf of the Swift Team:

At 01:08:30 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160716A (trigger=704572).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 190.544, -61.366 which is 
   RA(J2000) = 12h 42m 10s
   Dec(J2000) = -61d 21' 56"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a copmplex
structure with a duration of about 10 sec.  The peak count rate
was ~1500 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 01:09:55.7 UT, 85.7 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 190.43632, -61.35080 which is
equivalent to:
   RA(J2000)  = 12h 41m 44.72s
   Dec(J2000) = -61d 21' 02.9"
with an uncertainty of 4.0 arcseconds (radius, 90% containment). This
location is 193 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 9.61
x 10^21 cm^-2 (Willingale et al. 2013). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 88 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 large, but
uncertain extinction expected. 

Burst Advocate for this burst is L. M. Z. Hagen (lea.zernow.hagen 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: GRB160716A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19717
SUBJECT: GRB 160716A: Enhanced Swift-XRT position
DATE:    16/07/16 09:15:26 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 666 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 160716A, 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 = 190.43749, -61.35098 which is equivalent
to:

RA (J2000): 12h 41m 45.00s
Dec (J2000): -61d 21' 03.5"

with an uncertainty of 2.1 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: GRB160716A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19718
SUBJECT: GRB 160716A: Swift-XRT refined Analysis
DATE:    16/07/16 13:23:48 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

K.L. Page (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), B. Mingo (U. Leicester), A.P.
Beardmore (U. Leicester) and L.M.Z. Hagen report on behalf of the
Swift-XRT team:

We have analysed 6.7 ks of XRT data for GRB 160716A (Hagen et al. GCN
Circ. 19716), from 98 s to 24.2 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. 19717).

The light curve can be modelled with a power-law decay with a decay
index of alpha=0.87 (+0.15, -0.13).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.1 (+1.0, -0.8). The
best-fitting absorption column is  2.7 (+1.9, -1.4) x 10^22 cm^-2, in
excess of the Galactic value of 9.6 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 6.5 x 10^-11 (1.7 x 10^-10) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      2.7 (+1.9, -1.4) x 10^22 cm^-2
Galactic foreground: 9.6 x 10^21 cm^-2
Excess significance: 2.1 sigma
Photon index:      2.1 (+1.0, -0.8)

If the light curve continues to decay with a power-law decay index of
0.87, the count rate at T+24 hours will be 7.3 x 10^-4 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.8 x
10^-14 (1.2 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/00704572.

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


GRB_name: GRB160716A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19719
SUBJECT: GRB 160716A: Swift-BAT refined analysis
DATE:    16/07/16 14:36:32 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), L. M. Z. Hagen (PSU), 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+877 sec from the recent telemetry downlinks,
we report further analysis of BAT GRB 160716A (trigger #704572)
(Hagen, et al., GCN Circ. 19716).  The BAT ground-calculated position is
RA, Dec = 190.502, -61.364 deg, which is 
   RA(J2000)  =  12h 42m 00.6s 
   Dec(J2000) = -61d 21' 51.8" 
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 75%.
 
The mask-weighted light curve shows at least 2 overlapping peaks starting
at ~T-5sec, peaking at ~T+1 sec, and ending at ~T+20 sec.
T90 (15-350 keV) is 6.39 +- 0.57 sec (estimated error including systematics).
 
The time-averaged spectrum from T-0.43 to T+6.73 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.29 +- 0.30.  The fluence in the 15-150 keV band is 1.8 +- 0.3 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T+0.95 sec in the 15-150 keV band
is 0.8 +- 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/704572/BA/


GRB_name: GRB160714A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19720
SUBJECT: GRB 160714A: Swift/UVOT Upper Limits
DATE:    16/07/16 21:27:44 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@swift.psu.edu>

M. H. Siegel (PSU)reports on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 160714A
1682 s after the BAT trigger (Siegel et al., GCN Circ. 19697).
No optical afterglow consistent with the BAT position
is detected in the 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)        1682         1831          147         >20.14
white             1914         8131          292         >21.04
v                 1964         8542          293         >19.67
b                 1889         7926          293         >20.12
u                 1865         7720          490         >20.07
uvw1              1840         2908          293         >20.06
uvw2              1939         8336          235         >20.08

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: GRB160716A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19721
SUBJECT: GRB 160716A: Swift/UVOT Detection
DATE:    16/07/18 00:25:59 GMT
FROM:    Lea Hagen at PSU  <lea.zernow.hagen@gmail.com>

L. M. Z. Hagen (PSU) reports on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 160716A
88 s after the BAT trigger (Hagen et al., GCN Circ. 19716). A source
consistent with the XRT position (Evans et al., GCN Circ. 19717) is
detected in the initial UVOT exposures in the white filter. The source
has marginal evidence for fading but is not seen in the Digitized Sky
Survey (DSS), so it is unclear at this time whether it is the optical
afterglow. 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               88          773          183          19.93+-0.23
white             6218         6418          196          20.47+-0.35
white            24012        98905          490          20.62+-0.25
v                  631          651           19         >17.58
b                  556          750           38         >18.95
u                  301          725          265         >19.63
uvw1               681          701           19         >17.48
uvm2               656          676           19         >17.10
uvw2               607          627           19         >17.52


The magnitudes in the table are not corrected for the Galactic extinction
due to the large, but uncertain, reddening of E(B-V) = 1.47 in the
direction of the burst (Schlegel et al. 1998).


GRB_name: GRB160720A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19724
SUBJECT: GRB 160720A: Fermi GBM detection
DATE:    16/07/21 01:53:43 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007@uah.edu>

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

"At 18:23:57.00 UT on 20 July 2016, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 160720A (trigger 490731840 / 160720767).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 43, Dec = +76, with a statistical uncertainty of 1.00 degrees;
there is additionally a systematic error
which we have characterized as a core-plus-tail model, with 90% of GRBs
having a
3.7 deg error and a small tail suffering a larger than 10 deg systematic
error.
[Connaughton et al. 2015, ApJS, 216, 32].
The angle from the Fermi LAT boresight is 131 degrees.

The GBM light curve consists of several overlapping peaks with a duration
(T90)
of about 79 s (50-300 keV). The time-averaged spectrum from T0-1.02 to
T0+154 s is best fit by a power law function with an exponential
high-energy cutoff. The power law index is -1.12 +/- 0.01 and
the cutoff energy, parameterized as Epeak, is 191 +/- 3 keV.

The event fluence (10-1000 keV) in this time interval is (151 +/- 1)E-06
erg/cm^2. The 1-sec peak photon flux measured starting from T0+88 s in the
10-1000 keV band is 58 +/- 1 ph/s/cm^2.

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


GRB_name: GRB160703A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19725
SUBJECT: GRB 160703, GRB 160705, GRB 160720, SGR1935+2154: First SGRs and GRBs detected by Lomonosov.
DATE:    16/07/21 15:43:48 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

A.M.Amelushkin, V.O.Barinova, A.V.Bogomolov, V.V.Bogomolov, A.F.Iyudin,
V.V.Kalegaev, M.I.Panasyuk, V.L. Petrov, S.I.Svertilov, I.V.Yashin
Lomonosov Moscow State University, Physics Department, Skobeltsyn Institute
of Nuclear Physics, Moscow, Russia

E.S. Gorbovskoy, V.G.Kornilov, V.M. Lipunov
Lomonosov Moscow State University, Physics Department, Sternberg 
Astronomical Institute of M.V. Lomonosov Moscow, Moscow, Russia

I. Park, J. Lee, S. Jeong
Department of Physics, Sungkyunkwan University, Seobu-ro, Jangangu, 
Suwonsi, Korea

A.J.Castro-Tirado
IAA-CSIC, Granada, Spain


Russian space mission "Lomonosov" (*) ( http://lomonosov.sinp.msu.ru/en/ ) 
was launched 28.04.2016 from new Russian Kosmodrom  "Vostochny" to polar 
solar-synchronous orbit with altitude ~490 km. Scientific program of
"Lomonosov" includes a multi-wavelength GRB study at different time 
scales. In particular the complex study of prompt emission will be 
provided based on the direct  recording of readings of wide field optical 
cameras as well as on the fast pointing of optical and 
UV telescope using its moving mirror. The spacecraft "Lomonosov" contains 
3 instruments for GRB  study: gamma-ray burst monitor BDRG 
( http://lomonosov.sinp.msu.ru/en/scientific-equipment-2/bdrg ), a wide 
field optical camera SHOK ( http://lomonosov.sinp.msu.ru/en/scientific-equipment-2/shok 
) and UFFO ( http://lomonosov.sinp.msu.ru/en/scientific-equipment-2/uffo )
instrument consisting of coding mask X-ray telescope UBAT and UV slewing
mirror telescope SMT.

The Lomonosov GRB monitor BDRG is designed to obtain temporal and spectral 
information about GRBs in energy range 10-3000 keV as well as to produce 
GRB trigger.

The trigger is used onboard to fix some amount of data before GRB stored 
in the internal memory of all instruments of GRB complex as well as to 
start the detailed data collection. Immediately after the trigger the
onboard estimation of the GRB position starts. Then the telegram with 
trigger information is sent via Global Star transmitter to the server in 
MSU and, after automatic ground-based data processing (to exclude 
radiation belt zones etc.) to GCN (this will be  realized sometime later
after optimizing the trigger parameters during flight tests).

There are 3 GRBs and 5 SGR outbursts are detected to the present BDRG GRB 
monitor, which were also detected by other space missions and presented in 
GCN:

GRB 160703  12:10:02 UTC

GRB 160705  17:40:19 UTC

GRB 160720  18:27:55 UTC

Bursts from SGR1935+2154
18.06.2016 20:27:24 UTC,
20.06.2016 15:16:34 UTC, 
23.06.2016 21:20:45 UTC,
23.06.2016 21:23:35 UTC,
26.06.2016 13:54:29 UTC

Press release is available at 
http://lomonosov.sinp.msu.ru/wp-content/uploads/GRB_by_BDRG_engl_pdf.pdf

The message may be cited.

(*) About M.V.Lomonosov https://en.wikipedia.org/wiki/Mikhail_Lomonosov

[GCN OPS NOTE(30jul16): Per author's request, A.J.C-T. was added to the author list.]


GRB_name: GRB160720A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19726
SUBJECT: IPN Triangulation of GRB 160720A
DATE:    16/07/21 17:47:24 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@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,

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova,
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, and

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

The long-duration GRB 160720A (Hamburg and Burns, GCN Circ. 19724) has 
been detected by Fermi (GBM), Konus-Wind, INTEGRAL (SPI-ACS), and 
Mars-Odyssey (HEND), so far, at about 66237 s UT (18:23:57).

We have triangulated it to a preliminary, 3 sigma error box whose 
coordinates are:
   ---------------------------------------------
    RA(2000), deg                 Dec(2000), deg
   ---------------------------------------------
   Center:
     58.153 (03h 52m 37s) +73.893 (+73d 53' 33")
   Corners:
     62.806 (04h 11m 13s) +74.084 (+74d 05' 01")
     53.505 (03h 34m 01s) +74.329 (+74d 19' 44")
     53.637 (03h 34m 33s) +73.582 (+73d 34' 56")
     62.531 (04h 10m 07s) +73.338 (+73d 20' 17")
   ---------------------------------------------
The error box area is 1.9 sq. deg, and its maximum
dimension is 2.7 deg (the minimum one is 44.8 arcmin).
The Sun distance was 61 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB160720_T66314/IPN/

The Konus-Wind time history and spectrum will be given in a forthcoming 
GCN Circular.


GRB_name: GRB160720A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19727
SUBJECT: Konus-Wind observation of GRB 160720A
DATE:    16/07/21 18:15:18 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, P. Oleynik,
M. Ulanov,  A. Tsvetkova, A. Lysenko, A. Kozlova, and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration GRB 160720A
(Fermi-GBM detection: Hamburg and Burns, GCN Circ. 19724;
IPN triangulation: Hurley et al., GCN Circ. 19726)
triggered Konus-Wind at T0=66314.254 s UT (18:25:14.254).

The burst light curve shows a multipeaked structure
started at ~T0-80 s with a total duration of ~160 s.
The emission is seen up to ~2 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB160720_T66314/

As observed by Konus-Wind, the burst
had a fluence of 1.50(-0.05,+0.05)x10^-4 erg/cm2,
and a 64-ms peak flux, measured from T0+10.288 s,
of 1.31(-0.16,+0.16)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the most intense part
(measured from T0 to T0+27.392 s)
is best fit in the 20 keV - 3 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.87(-0.04,+0.04),
the high energy photon index beta = -2.87(-0.18,+0.14),
the peak energy Ep = 227(-8,+9) keV
(chi2 = 108/75 dof)

The spectrum near the maximum count rate
(measured from T0+9.728 to T0+10.496 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -0.82(-0.08,+0.09)
and Ep = 328(-28,+32) keV (chi2 = 66/54 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.7
(chi2 = 66/53 dof)

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


GRB_name: GRB160720A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19728
SUBJECT: GRB 160720A: Lomonosov BDRG gamma ray detection and MASTER limit
DATE:    16/07/21 20:28:26 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

A.M.Amelushkin, V.O.Barinova, A.V.Bogomolov, V.V.Bogomolov, A.F.Iyudin,
V.V.Kalegaev, M.I.Panasyuk, V.L. Petrov, S.I.Svertilov, I.V.Yashin
Physics Department, Skobel'tsyn Institute of Nuclear Physics, Moscow State 
University.

I. Park, J. Lee, S. Jeong
Department of Physics, Sungkyunkwan University, Seobu-ro, Jangangu, 
Suwonsi, Korea

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

R. Rebolo, M. Serra Ricart, N. Lodieu, G. Israelian
The Instituto de Astrofisica de Canarias

At 18:23:55.00 UT on 20 July 2016, the Lomonosov BDRG  Gamma-ray Burst 
Monitor (http://lomonosov.sinp.msu.ru/en/scientific-equipment-2/bdrg )
triggered GRB 160720A (Hamburg and Burns, GCN 19724).
GRB 160720A has  complicated LC, duration >87s, very
with  intensive peak between 18:25:12 - 18:25:22 .
Peak intensity >30 photons/cm2*s in the range 10-800 s.

This Notice was ground-generated.

MASTER-IAC robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in IAC (Tenerife) was cavered IPN error box (Hurley et al GCN 
19726)   GRB160720A error-box   23696 sec 
after notice time and 30794  sec after trigger time at 2016-07-21 02:57:11 
UT. The weather is  determined by Sahara dust. The 5-sigma upper limit
  is about 16.5  mag.

  The message may be cited.


GRB_name: GRB160720A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19729
SUBJECT: GRB 160720A CALET Gamma-Ray Burst Monitor detection
DATE:    16/07/23 02:03:16 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

S. Ozawa (Wasoeda U), A. Yoshida, T. Sakamoto, Y. Kawakubo, M. Moriyama,
Y. Yamada (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), I. Takahashi (IPMU),
Y. Asaoka, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena) and the CALET collaboration:

The long-duration GRB 160720A (Hamburg, et al., GCN circ. 19724;
Hurley, et al., GCN circ. 19726; Svinkin, et al. GCN circ. 19727;
Amelushkin, et al. GCN circ. 19728) triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 18:25:16.38 on 20 July 2016.  No real time CGBM
GCN notice was distributed about this trigger because the real time
communication from the ISS was off (loss of signal) between 17:57 and
18:45.  The burst signal was seen by all CGBM instruments.

The light curve of the SGM shows two main peaks.  The emission starts at
T-5 sec and ends at T+30 sec.  The peak times of the main pulses are T+3 sec
and T+10 sec.  The 3rd weak peak is visible at T+18 sec.  The T90 duration
measured by the SGM data is 36.4 +- 1.7 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1153074224/

The CALET data used in this analysis are provided by the Waseda
CALET Operation Center located at the Waseda University.


GRB_name: GRB160721A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19730
SUBJECT: GRB 160721A: CALET Gamma-Ray Burst Monitor detection
DATE:    16/07/24 12:03:56 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

S. Torii (Waseda U), A. Yoshida, T. Sakamoto, Y. Kawakubo, M. Moriyama,
Y. Yamada (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena) and the CALET collaboration:

The long-duration GRB 160721A (Fermi-GBM trigger #490821662;
INTEGRAL-ACS trigger #7516) triggered the CALET Gamma-ray Burst
Monitor (CGBM) at 19:20:58.54 on 21 July 2016.  The burst signal was
seen by all CGBM instruments.

The light curve of the SGM shows two short spikes with a broad emission.
The short spikes are peaked at T+0 sec and T+1.8 sec with the durations
less than a second.  The underline broad emission ends around T+10 sec.
The T90 duration measured by the SGM data is 8.6 +- 0.6 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1153163965/

The CALET data used in this analysis are provided by the Waseda
CALET Operation Center located at the Waseda University.


GRB_name: GRB160726A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19731
SUBJECT: GRB 160726A: Swift detection of a short burst
DATE:    16/07/26 01:50:31 GMT
FROM:    Kim Page at U.of Leicester  <klp5@leicester.ac.uk>

R. L. C. Starling (U Leicester), A. Y. Lien (GSFC/UMBC),
K. L. Page (U Leicester) and T. Sakamoto (AGU) report on behalf of the
Swift Team:

At 01:34:07 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160726A (trigger=706052).  Swift did not slew immediately
due to an observational constraint. 
The BAT on-board calculated location is 
RA, Dec 98.821, -6.644 which is 
   RA(J2000) = 06h 35m 17s
   Dec(J2000) = -06d 38' 39"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a double-peaked
structure with a duration of about 1 sec.  The peak count rate
was ~14000 counts/sec (15-350 keV), at ~0.7 sec after the trigger. 

Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 12:53 UT on 2016 August 10. There will thus be no XRT or
UVOT data for this trigger before this time. 

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: GRB160726A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19732
SUBJECT: GRB 160726A: Fermi GBM observation
DATE:    16/07/26 08:28:00 GMT
FROM:    Elisabetta Bissaldi at U.Innsbruk/IAPP  <Elisabetta.Bissaldi@uibk.ac.at>

R. Hamburg (UAH), E. Burns (UAH),
and E. Bissaldi (Politecnico & INFN Bari)
report on behalf of the Fermi GBM Team:

"At 01:34:07.72 UT on 26 July 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160726A (trigger 491189651 / 160726065),
which was also detected by the Swift/BAT
(Starling et al. 2016, GCN 19731).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi-LAT boresight at the GBM trigger time is 50 degrees.

The GBM light curve consists of two short peaks
with a duration (T90) of about 0.7 s (50-300 keV).
The time-averaged spectrum from T0-0.06 s to T0+0.77 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.0 +/- 0.1 and
the cutoff energy, parameterized as Epeak, is 540 +/- 100 keV.

The event fluence (10-1000 keV) in this time interval is
(1.01 +/- 0.05)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.06 s in the 10-1000 keV band
is 5.5 +/- 0.2 ph/s/cm^2.

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


GRB_name: GRB160726A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19733
SUBJECT: Konus-Wind observation of short GRB 160726A
DATE:    16/07/26 14:14:21 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

D. Frederiks, S. Golenetskii, R.Aptekar, P. Oleynik, M. Ulanov,
D. Svinkin, A. Tsvetkova, A.Lysenko, A. Kozlova, and T. Cline,
on behalf of the Konus-Wind team, report:

The short GRB 160726A (Swift/BAT detection: Starling et al., GCN 19731;
Fermi GBM observation: Hamburg et al., GCN 19732)
triggered Konus-Wind at T0=5645.315 s UT (01:34:05.315).

The light curve shows a short pulse with a total duration is ~0.2 s.
The emission is seen up to ~2 MeV.

As observed by Konus-Wind, the burst had a fluence of
(1.5 Â± 0.5)x10^-6 erg/cm2 and a 16-ms peak energy flux,
measured from T0+0.016, of (1.1 Â± 0.3)x10^-5 erg/cm2
(both in the 20 keV - 10 MeV energy range).

The spectrum of the burst (measured from T0 to T0+0.128 s)
is best fit in the 20 keV - 2 MeV range by a cutoff power-law
(CPL) function with the following model parameters:
the photon index alpha = -0.65(-0.47,+0.71),
and the peak energy Ep = 424(-163,+389) keV,
chi2 = 19.5/20 dof.
Fitting this spectrum with the GRB (Band) function yields
the same alpha and Ep with only an upper limit on beta of -1.8,
chi2 = 19.5/19 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB160726_T05645/

All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.


GRB_name: GRB160726A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19734
SUBJECT: GRB 160726A, Swift-BAT refined analysis
DATE:    16/07/27 01:18:02 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),
J. P. Norris (BSU), 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-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 160726A (trigger #706052)
(Starling et al., GCN Circ. 19731).  The BAT ground-calculated position is
RA, Dec = 98.809, -6.617 deg which is
  RA(J2000)  =  06h 35m 14.2s
  Dec(J2000) = -06d 37' 03.0"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 58%.

The mask-weighted light curve shows a double-peaked structure that
starts at ~T0 and ends at ~T+0.8 s, with the two peaks at ~ T0 and ~T+0.6 s,
respectively. T90 (15-350 keV) is 0.7 +- 0.04 sec (estimated error including
systematics).

The time-averaged spectrum from T+0.0 to T+0.8 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.26 +- 0.13.  The fluence in the 15-150 keV band is 2.6 +- 0.2 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.11 sec in the 15-150 keV band
is 3.2 +- 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

Using a 4-ms binned light curve, the lag analysis finds a lag of
is -3.5 +/- 3 ms for the 100-350 keV to 25-50 keV, and -5 +/- 6 ms for
the 50-100 keV to 15-25 keV band. These numbers are consistent with
those of a short GRB.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/706052/BA/


GRB_name: GRB160703A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19737
SUBJECT: GRB 160703A: 15 GHz upper limits from AMI
DATE:    16/07/28 17:38:09 GMT
FROM:    Kunal Mooley at Oxford U  <kunal.mooley@physics.ox.ac.uk>

K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson 
(Curtin), T. Cantwell (Manchester), C. Rumsey, D. Titterington, S. H. 
Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), 
K. Grainge, A. Scaife (Manchester)

The AMI Large Array robotically triggered on the Swift alert for GRB 
160703A (Cenko et al., GCN 19645) as part of the 4pisky program, and 
subsequent follow up observations were obtained up to 10 days 
post-burst. While the first observation on 2016 Jul 03.83 was severely 
affected by RFI, our observations at 15 GHz on 2016 Jul 04.99, Jul 
07.00, and Jul 11.00 (UT) do not reveal any radio source at the XRT 
location (D'Elia et al., GCN 19655), with 3sigma upper limits of 150 
uJy, 210 uJy, and 120 uJy respectively.

We thank the AMI staff for scheduling these observations. The AMI-GRB 
database is a log of all GRB follow up observations with the AMI, and is 
available at http://4pisky.org/ami-grb/.


GRB_name: GRB160705B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19738
SUBJECT: GRB 160705B: 15 GHz upper limits from AMI
DATE:    16/07/28 17:40:39 GMT
FROM:    Kunal Mooley at Oxford U  <kunal.mooley@physics.ox.ac.uk>

K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson 
(Curtin), T. Cantwell (Manchester), C. Rumsey, D. Titterington, S. H. 
Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), 
K. Grainge, A. Scaife (Manchester)

The AMI Large Array robotically triggered on the Swift alert for GRB 
160705B (Cannizzo et al., GCN 19657) as part of the 4pisky program, and 
subsequent follow up observations were obtained up to 10 days 
post-burst. Our observations at 15 GHz on 2016 Jul 05.89, Jul 06.73, Jul 
08.74, and Jul 12.72 (UT) do not reveal any radio source at the XRT 
location (Osborne et al., GCN 19659), with 3sigma upper limits of 177 
uJy, 102 uJy, 132 uJy, and 213 uJy respectively.

We thank the AMI staff for scheduling these observations. The AMI-GRB 
database is a log of all GRB follow up observations with the AMI, and is 
available at http://4pisky.org/ami-grb/.


GRB_name: GRB160703A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19739
SUBJECT: GRB160703A: Astrosat CZTI detection
DATE:    16/07/29 04:23:54 GMT
FROM:    Varun Bhalerao at IUCAA  <varunb@iucaa.in>

V. Bhalerao (IUCAA), V. Kumar (IUCAA), D. Bhattacharya (IUCAA), A. R. Rao (TIFR), S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:

Analysis of Astrosat data showed the CZTI detection of a long duration GRB 160703A (Swift/BAT observation:Cenko et al., GCN 19645, Swift/BAT triggered at 12:10:05 UT).

The GRB occured at an angle of 134 degrees away from the CZTI pointing direction. The source was clearly detected in the 40-200 keV energy range.  The light curve shows a complex structure, with a peak at UT 12:10:27.000. The peak count rate was 360.40 counts/sec above the background (four quadrants summed together), with a total of 5022.0 counts. The local mean background count rate was 352.0 counts/sec. Using cumulative rates, we measure a T90 of 45.0 secs.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb . CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB160709A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19740
SUBJECT: GRB160709A: Astrosat CZTI detection of short GRB
DATE:    16/07/29 04:24:51 GMT
FROM:    Varun Bhalerao at IUCAA  <varunb@iucaa.in>

V. Bhalerao (IUCAA), V. Kumar (IUCAA), D. Bhattacharya (IUCAA), A. R. Rao (TIFR), S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:

Analysis of Astrosat data showed the CZTI detection of a short GRB 160709A (Fermi-LAT detection: Guiriec, et al., GCN Circ. 19675).

The GRB occured at an angle of 124 degrees away from the CZTI pointing direction. The source was clearly detected in the 40-200 keV energy range. The light curve shows a single peak at 19:49:04.00 UT, 0.5 seconds after Fermi Trigger at 19:49:03.50 and a peak count rate of 1035.0 counts/sec above the background (four quadrants summed together), with a total of 3878.0 counts. The local mean background count rate was 314.0 counts/sec. Using cumulative rates, we measure a T90 of 0.45 sec, consistent with the Konus-Wind measurement of 0.4s (Frederiks et al., GCN Circ. 19677) and CALET (Asaoka et al., GCN Circ. 19701) but inconsistent with Swift-BAT (Sakamoto et al., GCN Circ. 19681) and Fermi (Jenke et al., GCN Circ. 19676).

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb . CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB160720A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19741
SUBJECT: GRB160720A: Astrosat CZTI detection
DATE:    16/07/29 04:25:22 GMT
FROM:    Varun Bhalerao at IUCAA  <varunb@iucaa.in>

V. Bhalerao (IUCAA), V. Kumar (IUCAA), D. Bhattacharya (IUCAA), A. R. Rao (TIFR), S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:

Analysis of Astrosat data showed the CZTI detection of GRB 160720A (Fermi-GBM detection: Hamburg and Burns, GCN Circ. 19724).

The source was clearly detected in the 40-200 keV energy range. The light curve shows a complex structure, with the strongest peak at 18:25:25 UT, 88 seconds after Fermi Trigger at 18:23:57.00 UT and a peak count rate of 318.0 counts/sec above the background (four quadrants summed together), with a total of 1813.0 counts. The local mean background count rate was 283.0 counts/sec. Using cumulative rates, we measure a T90 of 21.0 secs.

The center of the IPN Triangulation region (Hurley et al., GCN Circ.  19726) is at an angle of 143 degrees from the CZTI pointing direction.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb . CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB160716A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19742
SUBJECT: GRB 160716A: TAROT La Silla observatory optical observations
DATE:    16/07/29 21:58:47 GMT
FROM:    Alain Klotz at IRAP-CNRS-OMP  <Alain.Klotz@free.fr>

Klotz A., Turpin D., Atteia J.L. (CNRS-OMP-IRAP),
Boer, M., Laugier, R. (CNRS-ARTEMIS),
Gendre B. (UVI - Etelman Obs.) report:

We imaged the field of GRB 160716A detected by SWIFT
(trigger 704572) with the TAROT robotic telescope (D=25cm)
located at the European Southern Observatory,
La Silla observatory, Chile.

The observations started 43.6s after the GRB trigger
(15.6s after the notice). The elevation of the field decreased from
44 degrees above horizon and weather conditions
were good.

The first image is trailed with a duration of 60.0s
(see the description in Klotz et al., 2006, A&A 451, L39).
In the error box of XRT provided by Evans et al. (GCNC 19717)
we do not detect any OT with a limiting magnitude of:
t0+43.6s to t0+103.6s : Rlim = 16.7

The second image is 30.0s exposure in tracking mode:
t0+117.4s to t0+147.4s : Rlim = 17.5

We co-added a series of exposures:
t0+117.4s to t0+412.5s : Rlim = 18.2

Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.

N.B. Galactic coordinates are lon=301.8222 lat= +1.4859
and the galactic extinction in R band is about magnitudes.


GRB_name: GRB160801A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19744
SUBJECT: GRB 160801A: Swift detection of a burst
DATE:    16/08/01 09:48:44 GMT
FROM:    Valerio D'Elia at ASDC  <delia@asdc.asi.it>

V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), P.A. Evans (U Leicester),
H. A. Krimm (CRESST/GSFC/USRA) and A. Y. Lien (GSFC/UMBC) report on
behalf of the Swift Team:

At 09:28:30 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160801A (trigger=706871).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 212.763, +13.499 which is 
   RA(J2000) = 14h 11m 03s
   Dec(J2000) = +13d 29' 58"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single-peaked
structure with a duration of about 7 sec.  The peak count rate
was ~2000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 09:29:57.4 UT, 87.0 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 212.7629, 13.4895 which
is equivalent to:
   RA(J2000)  = 14h 11m 03.10s
   Dec(J2000) = +13d 29' 22.3"
with an uncertainty of 2.5 arcseconds (radius, 90% containment). This
location is 34 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 1.59
x 10^20 cm^-2 (Willingale et al. 2013). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 90 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.02. 

Burst Advocate for this burst is 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: GRB160801A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19745
SUBJECT: GRB 160801A: MITSuME Okayama upper limits
DATE:    16/08/01 14:00:37 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 160801A (D'Elia et al., GCNC 19744)
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 2016-08-01 11:06:56 UT (~1.6 h after
the burst). We did not find any new point source within the XRT
circle (D'Elia et al., GCNC 19744) in all the three bands.

Three sigma upper limits of the OT are listed below.
We used SDSS-DR8 catalog for flux calibration.

#T0+[day]  MID-UT    T-EXP[sec]   g'    Rc     Ic
-----------------------------------------------------
0.10264    11:56:18    2580.0   >19.1  >19.2  >18.6
-----------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]


GRB_name: GRB160801A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19746
SUBJECT: GRB 160801A: Enhanced Swift-XRT position
DATE:    16/08/01 14:22:07 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 1870 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 160801A, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 212.76274, +13.48921 which is equivalent
to:

RA (J2000): 14h 11m 3.06s
Dec (J2000): +13d 29' 21.1"

with an uncertainty of 2.0 arcsec (radius, 90% confidence).

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

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


GRB_name: GRB160801A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19749
SUBJECT: GRB 160801A: Swift-BAT refined analysis
DATE:    16/08/01 17:43:33 GMT
FROM:    Hans Krimm at NASA-GSFC  <hans.a.krimm@nasa.gov>

J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), V. D'Elia (ASDC),
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-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 160801A (trigger #706871)
(D'Elia, et al., GCN Circ. 19744).  The BAT ground-calculated position is
RA, Dec = 212.763, 13.485 deg which is
    RA(J2000)  =  14h 11m 03.2s
    Dec(J2000) = +13d 29' 06.5"
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 73%.

The mask-weighted light curve shows a single peak with ~3 second duration,
peaking at T+0. T90 (15-350 keV) is 2.85 +- 0.41 sec (estimated error including
systematics).

The time-averaged spectrum from T-1.34 to T+1.83 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.85 +- 0.22.  The fluence in the 15-150 keV band is 1.7 +- 0.3 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.02 sec in the 15-150 keV band
is 1.2 +- 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/706871/BA/


GRB_name: GRB160801A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19750
SUBJECT: GRB 160801A: Swift-XRT refined Analysis
DATE:    16/08/01 20:11:10 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), D.N. Burrows (PSU),
T.G.R. Roegiers (PSU), L.M. McCauley (PSU), B. Mingo (U. Leicester),
A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester) and V. D'Elia
report on behalf of the Swift-XRT team:

We have analysed 6.5 ks of XRT data for GRB 160801A (D'Elia et al. GCN
Circ. 19744), from 96 s to 19.2 ks after the  BAT trigger. The data are
entirely in Photon Counting (PC) mode. The enhanced XRT position for
this burst was given by Goad et al. (GCN Circ. 19746).

The light curve can be modelled with a power-law decay with a decay
index of alpha=0.94 (+0.13, -0.11).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.1 (+0.6, -0.5). The
best-fitting absorption column is  6.0 (+3.9, -2.8) 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 4.0 x 10^-11 (7.3 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      6.0 (+3.9, -2.8) x 10^21 cm^-2
Galactic foreground: 1.6 x 10^20 cm^-2
Excess significance: 3.5 sigma
Photon index:      2.1 (+0.6, -0.5)

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 5.8 x 10^-4 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.3 x
10^-14 (4.2 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/00706871.

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


GRB_name: GRB160726A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19751
SUBJECT: GRB 160726A: CALET Gamma-Ray Burst Monitor detection
DATE:    16/08/01 21:03:22 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

Y. Shimizu (Kanagawa U), A. Yoshida, T. Sakamoto, Y. Kawakubo, M. Moriyama,
Y. Yamada (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U), T. Tamura (Kanagawa U), W. Ishizaki (ICRR),
M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The short-duration GRB 160726A (Starling, et al., GCN circ. 19731;
Hamburg, et al., GCN circ. 19732; Frederiks, et al. GCN circ. 19733)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 01:34:08.25
on 26 July 2016.  The burst signal was seen by all CGBM instruments.

The light curve of the SGM shows two peaks.  The first weak episode
peaks at T-0.55 s.  The second peak starts at T-0.1 s, peaks at T+0.1 s
and ends at T+0.3 s.  The T90 duration measured by the SGM data is
0.83 +- 0.09 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1153531947/

The CALET data used in this analysis are provided by the Waseda
CALET Operation Center located at the Waseda University.


GRB_name: GRB160801A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19753
SUBJECT: GRB 160801A: NOT upper limits
DATE:    16/08/02 11:40:16 GMT
FROM:    Zach Cano at U of Iceland  <zewcano@gmail.com>

Z. Cano (Univ. Iceland), D. Malesani (DARK/NBI and DTU space), J.-K.
Krogager, P. Noterdaeme (IAP) & A. Djupvik (NOT) report on behalf of a
larger collaboration:

We observed the field of GRB 160801A (D'Elia et al.; GCN Circ. 19744) with
the 2.5-m Nordic Optical Telescope equipped with ALFOSC, starting at 21:05
UT on 01 August 2016.  We obtained 14 minutes in the z-band and 10 minutes
in the r-band.  In our co-added images we do not detect any new source(s)
within the enhanced XRT error circle (Goad et al.; GCN Circ. 19746) to the
following limits:

Filter    t-t0 (d)     magnitude limit (AB)
-------------------------------------------
  r       0.50               >24.4
  z       0.49               >23.1

These upper limits are for an isolated point source in the GRB field, they
are calibrated against the SDSS catalogue, and they have not been corrected
for foreground extinction.

We note the presence of an SDSS object (RA = 14:11:03.21, Dec =+13:29:21.5)
just outside the refined XRT error circle. This object is pointlike in our
images (0.8" seeing) and its magnitude did not vary within the errors
compared to the SDSS archival values. We consider it is unlikely that this
object is associated with GRB 160801A.


GRB_name: GRB160802A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19754
SUBJECT: GRB 160802A: Fermi GBM detection
DATE:    16/08/02 13:08:10 GMT
FROM:    Elisabetta Bissaldi at U.Innsbruk/IAPP  <Elisabetta.Bissaldi@uibk.ac.at>

E. Bissaldi (Politecnico & INFN Bari)
reports on behalf of the Fermi GBM Team:


"At 06:13:29.63 UT on 02 August 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160802A (trigger 491811213 / 160802259).
The on-ground calculated location, using the GBM trigger data, is

RA, Dec =  35.29, +72.69

(J2000 degrees, equivalent to 02h 21m, 72d 41'),
with an uncertainty of 1 degree (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which we have characterized as a core-plus-tail model, with 90% of
GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg
systematic error [Connaughton et al. 2015, ApJS, 216, 32].

The trigger resulted in an Autonomous Repoint Request (ARR)
by the GBM Flight Software owing to the high peak flux
of the GRB. This ARR was accepted and the spacecraft slewed
to the GBM in-flight location. The initial angle from the
Fermi LAT boresight to the GBM ground location is 106 degrees.

The GBM light curve consists of 2 FRED-like peaks
with a duration (T90) of about 16.4 s (50-300 keV).
The time-averaged spectrum from T0-0.3 s to T0+19.4 s is
best fit by a Band function with Epeak = 284 +/- 7 keV,
alpha = -0.71 +/- 0.02, and beta = -2.44 +/- 0.06.

The event fluence (10-1000 keV) in this time interval is
(1.04 +/- 0.08)E-04 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.7 s in the 10-1000 keV band
is 72.5 +/- 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: GRB160801A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19755
SUBJECT: GRB 160801A: SAO RAS optical observations
DATE:    16/08/02 14:33:46 GMT
FROM:    Moskvitin Alexander at SAO RAS  <mosk@sao.ru>

A. Moskvitin (SAO RAS) and I. Soloviev  (Saint-Petersburg Univ.),
report on behalf of the larger GRB follow-up team.

We observed the field of GRB 160801A (D'Elia et al., GCNC#19744)
with Zeiss-1000 - the 1-meter telescope of Special Astrophysical
Observatory of Russian Academy of Sciences on August 1, 2016,
(18:14:58--20:09:29 UT), T_mid - T0 = 9.73 hours. We have obtained
18 x 300 sec. images in the Rc band under good weather conditions.
Within the XRT error circle (Goad et al., GCNC#19746)
we did not detect any new objects down to the limiting magnitude
R_lim = 23.2.

When inspecting SDSS images we found a faint stellar-like source
J141103.21+132921.4 located near the enhanced XRT error circle.
The recalculated magnitude of the object from SDSS images
(Epoch = 2003.41) should be R = 20.94 +/- 0.05 (based on the
Lupton 2005 equations).

In our stacked frame at the edge of the XRT error circle
(the offset 2".2) we detected the same source with a brightness of
R = 20.9 +/- 0.1. Therefore, we can not detect significant differences
between two epochs. This result is in agreement with info reported
by Cano et al. (GCNC#19753). Our preliminary photometry is based
on the nearby SDSS stars, which magnitudes are converted to the
Johnson-Cousins system with the same Lupton 2005 equations.

The finding chart based on Zeiss-1000 observations can be found at
ftp://ftp.sao.ru/pub/grb/GRB160801A/GRB160801A_z1000.jpg

We are grateful to technical staff of SAO RAS for assistance in
observations.

<ftp://ftp.sao.ru/pub/grb/GRB160801A/GRB160801A_z1000.jpg>


GRB_name: GRB160801A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19756
SUBJECT: GRB 160801A: Swift/UVOT Upper Limits
DATE:    16/08/02 20:48:04 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@swift.psu.edu>

B. G. Balzer (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 160801A
90 s after the BAT trigger (D'Elia et al., GCN Circ. 19744).
No optical afterglow consistent with the XRT position
(Goad et al. GCN Circ. 19746)
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 the subsequent summed exposures:

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

white_FC            90          240          147         >20.50
u_FC               302          552          245         >19.91
white              581         1896          283         >20.94
v                  631         1945          155         >18.91
b                  557         1871          136         >19.90
u                  704         1846          116         >19.48
w1                1455         1474           19         >17.77

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: GRB160801A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19757
SUBJECT: GRB 160801A: TSHAO optical observations
DATE:    16/08/02 22:45:50 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI), A. Kusakin (Fesenkov Astrophysical Institute), I. Reva 
(Fesenkov Astrophysical Institute),  A. Pozanenko (IKI) report on behalf of 
larger GRB follow-up collaboration:

We observed the field of GRB 160801A  (D'Elia et al., GCN 19744 ) with 
Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical Observatory. We 
obtained several images in R filter starting on August 01 (UT) 15:10:55. We 
do not  detect any optical source within enhanced XRT error position (Goad 
et al., GCN 19746). Preliminary photometry of a combined image is following

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

2016-08-01 15:10:55  0.28422  R   60*120 n/d  n/d  22.4

Photometry is based on nearby SDSS DR9 stars
SDSS-DR9_id                   R(Lupton)
J141100.70+132838.3    17.993
J141057.03+132833.7    17.684
J141054.86+132751.0    18.338
J141055.05+132937.2    18.545
J141059.52+133105.4    19.518
J141102.35+133019.9    18.384
J141102.64+133004.5    18.354

Our preliminary  photometry of the SDSS object (Cano et al.,  GCN 19753) 
which is also mentioned by Moskvitin et al. (GCN 19755)  is R=21.1+/-0.1 and 
based on the same nearby SDSS stars.

A finding chart can be found  in 
http://grb.rssi.ru/GRB160801A/GRB160801A_TSHAO_160801_2.png 


GRB_name: GRB160802A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19759
SUBJECT: GRB 160802A: Lomonosov BDRG gamma ray detection
DATE:    16/08/03 15:11:25 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

M.I.Panasyuk, S.I.Svertilov, V.V.Bogomolov, A.M.Amelushkin, V.O.Barinova, 
A.V.Bogomolov, A.F.Iyudin, V.V.Kalegaev, D.Nguen,  V.L. Petrov, 
I.V.Yashin
Physics Department, Skobel'tsyn Institute of Nuclear Physics, Moscow State

V. Lipunov, E.S. Gorbovskoy, N.Tyurina
Lomonosov Moscow State University, Sternberg Astronomical Institute

I. Park, J. Lee, S. Jeong
Department of Physics, Sungkyunkwan University, Seobu-ro, Jangangu, 
Suwonsi, Korea

At 06:13:29.30 UT on 02 Aug 2016, the Lomonosov BDRG  Gamma-ray Burst 
Monitor  (http://lomonosov.sinp.msu.ru/en/scientific-equipment-2/bdrg )
triggered GRB 160802A (Bissaldi, GCN 19754).
GRB 160802A has  complicated LC, two peaks, total duration 20s duration,
with peak intensity >30 photons/cm2*s in the range 20-300 keV.
This Notice was ground-generated.
The message may be cited.


GRB_name: GRB160804A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19761
SUBJECT: GRB 160804A: Swift detection of a burst
DATE:    16/08/04 03:18:08 GMT
FROM:    Jamie A. Kennea at PSU/Swift-XRT  <kennea@swift.psu.edu>

F. E. Marshall (NASA/GSFC), P. D'Avanzo (INAF-OAB),
J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), A. Melandri (INAF-OAB) and
M. H. Siegel (PSU) report on behalf of the Swift Team:

At 01:32:47 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160804A (trigger= 707231 ).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 221.639, +10.001 which is 
   RA(J2000) =  14h 46m 33.4s
   Dec(J2000) = +10d 00m 03.6s
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty). 

The XRT began observing the field at 01:35:14 UT, 147 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 221.62909, +9.99599 which
is equivalent to:
   RA(J2000)  = 14h 46m 31.0s
   Dec(J2000) = +09d 59m 45.6s
with an uncertainty of 5 arcseconds (radius, 90% containment). This
location is 39 arcseconds from the BAT onboard position, within the BAT
error circle. 

Due to bad weather near Guam, we only have limited information about
this burst at this time. More information will be available after a
full ground station pass. 

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: GRB160804A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19762
SUBJECT: GRB 160804A: Enhanced Swift-XRT position
DATE:    16/08/04 07:10:30 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 2427 s of XRT Photon Counting mode data and 5 UVOT
images for GRB 160804A, 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 = 221.62988, +9.99889 which is equivalent
to:

RA (J2000): 14h 46m 31.17s
Dec (J2000): +09d 59' 56.0"

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: GRB160804A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19763
SUBJECT: GRB 160804A: Swift-XRT refined Analysis
DATE:    16/08/04 09:39:09 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), T.G.R. Roegiers (PSU), L.M.
McCauley (PSU), J.A. Kennea (PSU), A.P. Beardmore (U. Leicester), P.A.
Evans (U. Leicester), S.L. Gibson (U. Leicester), A. D'Ai (INAF-IASFPA)
and F.E. Marshall report on behalf of the Swift-XRT team:

We have analysed 6.1 ks of XRT data for GRB 160804A (Marshall et al.
GCN Circ. 19761), from 137 s to 18.0 ks after the  BAT trigger. The
data comprise 600 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. 19762).

The late-time light curve (from T0+4.3 ks) can be modelled with a
power-law decay with a decay index of alpha=0.32 (+0.20, -0.19).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.772 (+/-0.023). The
best-fitting absorption column is  1.44 (+/-0.08) x 10^21 cm^-2, in
excess of the Galactic value of 1.9 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.90 (+0.17, -0.16)
and a best-fitting absorption column of 7.1 (+4.3, -3.8) x 10^20 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 3.4 x 10^-11 (4.0 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      7.1 (+4.3, -3.8) x 10^20 cm^-2
Galactic foreground: 1.9 x 10^20 cm^-2
Excess significance: 2.2 sigma
Photon index:      1.90 (+0.17, -0.16)

If the light curve continues to decay with a power-law decay index of
0.32, the count rate at T+24 hours will be 0.049 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.7 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/00707231.

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


GRB_name: GRB160804A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19764
SUBJECT: GRB 160804A: Swift/UVOT Detection
DATE:    16/08/04 11:40:54 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld@ucl.ac.uk>

A. A. Breeveld (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 160804A 82 
s after the BAT trigger (Marshall et al., GCN Circ. 19761).
A fading source consistent with the XRT position (Osborne et al. GCN 
Circ. 19762) is detected in the initial UVOT exposures.

The preliminary UVOT position is:
     RA  (J2000) =  14:46:31.14 = 221.62976 (deg.)
     Dec (J2000) = +09:59:56.7  =   9.99908 (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               82          232          147         18.56 Â± 0.06
white              794          944          148         19.66 Â± 0.12
v                  570         6762          373        >19.9
b                  496         6227          432         20.4  Â± 0.24
u                  240          490          246         19.53 Â± 0.20
w1                4182         4382          197         18.90 Â± 0.25
m2                1000         5612          216        >18.7
w2                 546         6637          432        >19.5

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: GRB160804A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19765
SUBJECT: GRB 160804A: Swift-BAT refined analysis
DATE:    16/08/04 12:31:07 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@lheamail.gsfc.nasa.gov>

H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
F. E. Marshall (NASA/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 recent telemetry downlinks,
we report further analysis of BAT GRB 160804A (trigger #707231)
(Marshall, et al., GCN Circ. 19761).  The BAT ground-calculated position is
RA, Dec = 221.652, 10.002 deg, which is 
   RA(J2000)  =  14h 46m 36.4s 
   Dec(J2000) = +10d 00' 06.2" 
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 28%.
 
The mask-weighted light curve shost several overlapping peaks starting
at ~T+20sec (possibly at ~T-30 sec), peaking at ~T+90 sec, and returning
to baseline at ~T+330 sec.  T90 (15-350 keV) is 144.2 +- 19.2 sec
(estimated error including systematics).
 
The time-averaged spectrum from T+25.14 to T+247.15 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 1.40 +- 0.23, 
and Epeak of 52.7 +- 5.4 keV (chi squared 57.0 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 1.14 +- 0.03 x 10^-5 erg/cm2
and the 1-sec peak flux measured from T+88.59 sec in the 15-150 keV band is
2.9 +- 0.3 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.99 +- 0.05 (chi squared 79.05 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/707231/BA/


GRB_name: GRB160802A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19766
SUBJECT: IPN Triangulation of GRB 160802A
DATE:    16/08/04 17:54:39 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@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,

A. Kozlova, S. Golenetskii, R. Aptekar, 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, and

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

The bright long-duration GRB 160802A has been detected by
Fermi (GBM: Bissaldi, GCN Circ. 19754), Konus-Wind, Mars-Odyssey (HEND),
and INTEGRAL (SPI-ACS), so far, at about 22410 s UT (06:13:30).

We have triangulated it to a preliminary, 3 sigma error box whose
coordinates are:
 ---------------------------------------------
  RA(2000), deg                 Dec(2000), deg
 ---------------------------------------------
 Center:
   28.027 (01h 52m 07s) +71.370 (+71d 22' 10")
 Corners:
   26.646 (01h 46m 35s) +71.433 (+71d 26' 00")
   28.172 (01h 52m 41s) +71.786 (+71d 47' 09")
   29.401 (01h 57m 36s) +71.295 (+71d 17' 41")
   27.891 (01h 51m 34s) +70.952 (+70d 57' 08")
 ---------------------------------------------
The error box area is 1343 sq. arcmin, and its maximum
dimension is 53 arcmin (the minimum one is 36 arcmin).
The Sun distance was about 78 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB160802_T22409/IPN/

The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.


GRB_name: GRB160802A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19767
SUBJECT: Konus-Wind observation of GRB 160802A
DATE:    16/08/04 17:58:30 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks, 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 160802A
(Fermi GBM observation: Bissaldi, GCN 19754;
Lomonosov BDRG GRBM detection: Panasyuk et al., GCN 19759;
IPN triangulation: Hurley et al., GCN 19766 )
triggered Konus-Wind at T0=22409.945 s UT (06:13:29.945).

The burst light curve shows a multipeaked structure
started at ~T0-0.1 s with a total duration of ~20.0 s.
The emission is seen up to ~3 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB160802_T22409/

As observed by Konus-Wind, the burst
had a fluence of 8.37(-0.47,+0.50)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+0.976 s,
of 3.27(-0.41,+0.42)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+20.224 s)
is best fit in the 20 keV - 3 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.74(-0.05,+0.05),
the high energy photon index beta = -2.43(-0.12,+0.10),
the peak energy Ep = 273(-14,+15) keV
(chi2 = 111/68 dof)

The spectrum near the maximum count rate
(measured from T0+0.768 to T0+1.280 s)
is best fit in the 20 keV - 3 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.14(-0.14,+0.15),
the high energy photon index beta = -2.42(-0.24,+0.16),
the peak energy Ep = 306(-30,+36) keV
(chi2 = 73/51 dof)

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


GRB_name: GRB160804A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19768
SUBJECT: GRB160804A: MASTER-SAAO observation
DATE:    16/08/04 19:50:30 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

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

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

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

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

V.Yurkov, Yu.Sergienko, A.Gabovich
Blagoveschensk Educational State University, Blagoveschensk

H.Levato , C.Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

F. Podest, C. Mallamaci, C. Lopez , R.Podesta
Observatorio Astronomico Felix Aguilar (OAFA)

R. Rebolo, M. Serra Ricart, N. Lodieu, G. Israelian
The Instituto de Astrofisica de Canarias



MASTER-SAAO  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in SAAO was pointed to the  GRB160804A  (Swift trigger= 707231 
came only from (Marshall et al., GCN19761)
  at 2016-08-04 17:59:48 UT (16h27m01s after the trigger time). We have set 
of  images with unfiltered 
m_lim=20.7 (540s exposure).

We see the Swift/UVOT source (Breeveld et al., GCN 19764) at Ra Dec 
(2000)=14:46:31.14 +09:59:56.7  with unfiltered m_OT~ 20.3.

There is  a Sloan galaxy  in 0.182" with green g=21.7, red r=21.2m, i.e. 
possible host galaxy for this GRB.


GRB_name: GRB160804A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19769
SUBJECT: GRB 160804A: Fermi GBM observation
DATE:    16/08/04 21:54:43 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007@uah.edu>

E. Bissaldi (Politecnico & INFN Bari), C. M. Hui (MSFC),
V. Connaughton (USRA), and Rachel Hamburg (UAH)
report on behalf of the Fermi GBM Team:


"At 01:34:16.04 UT on 04 August 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160804A (trigger 491967260 / 160804065),
which was also detected by the Swift-BAT (Marshall et al. 2016, GCN 19761).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 87
degrees.

The GBM light curve consists of single emission episode
with a duration (T90) of about 130 s (50-300 keV).
The time-averaged spectrum from T0-60 s to T0+70 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.1 +/- 0.1 and
the cutoff energy, parameterized as Epeak, is 74 +/- 3 keV.

The event fluence (10-1000 keV) in this time interval is
(1.5 +/- 0.3)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+10 s in the 10-1000 keV band
is 4.6 +/- 0.3 ph/s/cm^2.


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


GRB_name: GRB160804A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19770
SUBJECT: GRB 160804A: TNG optical observations, afterglow fading and candidate host galaxy
DATE:    16/08/04 23:12:21 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>

D. Malesani (DARK/NBI and DTU Space), P. D'Avanzo (INAF/OABr), A. Melandri
(INAF/OABr), V. D'Elia (INAF/Roma and ASI/ASDC), A. Garcia de Gurtubai
Escudero (INAF/TNG), and M. Pedani (INAF/TNG), report on behalf of the CIBO
collaboration:

We observed the field of GRB 160804A (Marshall et al., GCN 19761) with 
the Telescopio Nazionale Galileo (TNG) equipped with DOLoRes. 
Observations were carried out in the r and z filters.

At the position of the optical afterglow (Breeveld & Marshall, GCN 
19764), we clearly detect an extended object in both filters. 
Calibrating compared to nearby SDSS stars, we measure AB magnitudes r = 
20.99 +- 0.04 and z = 19.99 +- 0.17. The mid time of the observations is 
Aug 4.89 UT, that is 0.83 days after the trigger.

We note that this object is clearly visible in the SDSS frames, with 
catalog magnitudes of r = 21.22 +- 0.11 and z = 20.74 +- 0.35. It is 
classified as a galaxy with a (fairly uncertain) photometric redshift z 
<~ 0.5  This object is most likely the host galaxy of GRB 160804A.

Our measurements are marginally (2 sigma) brighter than the SDSS values, 
though we caution that aperture effects on a low S/N extended object may 
be responsible for the difference. In any case, the afterglow is only 
contributing little flux at the epoch of the TNG observations.


[GCN OPS NOTE(05aug16): Per author's request, AGdGE was added to the author list.]


GRB_name: GRB160804A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19771
SUBJECT: GRB 160804A: SAO RAS optical observations
DATE:    16/08/05 01:07:20 GMT
FROM:    Moskvitin Alexander at SAO RAS  <mosk@sao.ru>

A. S. Moskvitin, T. A. Fatkhullin (SAO RAS, Russia) and I. Soloviev
(Saint-Petersburg Univ.), report on behalf of the larger team.

We observed the field of the GRB 160804A (Marshall et al., GCN 19761)
with the BTA, 6-meter telescope of SAO RAS, equipped with the
Scorpio-I at 2016.08.04 17:52 UT (16.3 hours after the detection).

A couple of Rc-band images (30 and 180 sec.) were obtained.
The GRB OT (Breeveld & Marshall, GCN 19764; Tyurina et al., GCN 19768)
is clearly detected in the stacked frame. The brightness of the object
is R = 20.5 +/- 0.1 (calibration was done by the nearby SDSS stars,
and Lupton 2005 transformation equations).

The finding chart can be found at
ftp://ftp.sao.ru/pub/grb/GRB160804A/GRB180804A_BTA.jpg


GRB_name: GRB160804A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19773
SUBJECT: GRB 160804A: VLT/X-shooter redshift
DATE:    16/08/05 08:05:36 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

D. Xu (NAOC), K. E. Heintz (DARK/NBI), D. Malesani (DARK/NBI and DTU 
Space), K. Wiersema (U. Leicester), J. P. U. Fynbo (DARK/NBI), report on 
behalf of a larger collaboration:

We observed the optical afterglow of GRB 160804A (Marshall et al., GCN 
19761; Breeveld et al., GCN 19764) with the ESO VLT UT2 (Kueyen) 
equipped with the X-shooter spectrograph. Observations started at 23:55 
UT on 2016-08-04 (22.37 hr after the BAT trigger) and consisted of 4 
spectra by 600 s each, covering the wavelength range 3500-20000 AA.

The continuum trace is well detected in our exposures, down to ~3100 AA.
The lack of any drop sets an upper limit to the redshift z < 1.55. A 
number of superimposed absorption features are detected, which we 
interpret as due to Mg I, Mg II, Fe II, Al II, as well as emission 
features due to [O II], [O III], Halpha, Hbeta, Hgamma, [N II], [S II], 
[S III], all at a common redshift z = 0.736. We thus conclude this is 
the redshift of GRB 160804A.

We acknowledge excellent support from the ESO observing staff in 
Paranal, in particular Jonathan Smoker, Leo Rivas, and Stephane Brillant.


GRB_name: GRB160804A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19774
SUBJECT: GRB 160804A: GROND observations
DATE:    16/08/05 15:06:51 GMT
FROM:    Jan Bolmer at MPE/Garching  <jan@bolmer.de>

J. Bolmer and J. Greiner (both MPE Garching) report on behalf
of the GROND team:

We observed the field of GRB 160804A (Swift trigger 707231; Marshall et
al., GCN #19761) simultaneously in g'r'i'z'JHK with GROND (Greiner
et al. 2008, PASP 120, 405) mounted at the 2.2m MPG telescope at the
ESO La Silla Observatory (Chile).

Observations started at 23:12:02 UT on 2016-08-04, 21.7 hr after the GRB
trigger. They were performed at an average seeing of 1.3", at an
average airmass of 1.5.

We clearly detect the source reported by Breeveld et al. (GCN #19764), Tyurina et al.
(GCN #19768), Malesani et al. (GCN #19770), Moskvitin et al. (GCN #19771)
and Xu et al. (GCN #19773).

Based on images with 84 min of total exposure in g'r'i'z'
and 80 min in JHK at a mid-time of 00:15:10 UT on 2016-08-05,
we derive the following preliminary magnitudes (all in AB system):

g' = 21.50 +- 0.03 mag
r' = 21.21 +- 0.03 mag
i' = 20.85 +- 0.03 mag
z' = 20.66 +- 0.03 mag
J = 20.20 +- 0.07 mag
H = 19.88 +- 0.07 mag
K = 19.69 +- 0.12 mag

Given magnitudes are calibrated against SDSS as well as 2MASS
field stars 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 (Schlafly & Finkbeiner 2011).

We note that our râ€™- and zâ€™-band magnitudes are consistent with
the SDSS catalog magnitudes of the host galaxy (as reported by Malesani et
al., GCN #19770).


GRB_name: GRB160804A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19775
SUBJECT: GRB 160804A: ISON/UAFO optical observations
DATE:    16/08/05 15:40:06 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI),  E. Chornaya (UAFO, ISON), A. Matkin (UAFO), I. 
Molotov (KIAM), A. Pozanenko (IKI) report on behalf of  larger GRB 
follow-up collaboration:

We observed the field of GRB 160804A  (Marshall et al., GCN 19761)  with 
SANTEL-650 (0.65m)  telescope  of UAFO/ISON-Ussuriysk observatory. We 
obtained several unfiltered images  starting on  August 04 (UT) 
12:03:56.  We clearly detected  optical source reported by Breeveld et 
al. (GCN 19764), Tyurina et al. (GCN 19768), Malesani et al. (GCN 
19770), Moskvitin et al. (GCN 19771), Xu et al. (GCN #19773) and Bolmer 
et al. (GCN 19774). Preliminary photometry of a combined image is following

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

2016-08-04 12:03:56 0.46189  CR      60*120 19.90  0.27  21.6

Photometry is based on nearby SDSS DR9 stars
SDSS-DR9_id    R(Lupton)
J144642.43+100147.7    18.068
J144642.15+100017.4    17.644
J144638.04+095917.6    17.971
J144635.67+095910.6    18.378
J144619.22+095958.1    16.677
J144616.60+100018.4    16.575
J144614.88+100001.4    16.544


GRB_name: GRB160804A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19776
SUBJECT: GRB 160804A: TSHAO optical observations
DATE:    16/08/05 15:44:31 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI), A. Kusakin (Fesenkov Astrophysical Institute), 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 GRB 160804A  (Marshall et al., GCN 19761)  with 
Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical Observatory. 
We obtained several images in R filter starting on August 04 (UT) 
15:08:18. We clearly detected  optical source reported by Breeveld et 
al. (GCN 19764), Tyurina et al. (GCN 19768), Malesani et al. (GCN 
19770), Moskvitin et al. (GCN 19771), Xu et al. (GCN #19773) and Bolmer 
et al. (GCN 19774). Preliminary photometry of a combined image is following

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

2016-08-04 15:08:18 0.58601  R       26*120 20.30  0.10  21.4

Photometry is based on nearby SDSS DR9 stars

SDSS-DR9_id    R(Lupton)
J144642.43+100147.7    18.068
J144642.15+100017.4    17.644
J144638.04+095917.6    17.971
J144635.67+095910.6    18.378
J144632.91+100104.9    17.910
J144619.22+095958.1    16.677
J144616.60+100018.4    16.575
J144614.88+100001.4    16.544


GRB_name: GRB160726A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19777
SUBJECT: IceCube-160731A: Konus-Wind limits
DATE:    16/08/05 15:52:16 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

D. Frederiks, S. Golenetskii, R.Aptekar, P. Oleynik, M. Ulanov,
D. Svinkin, A. Tsvetkova, A.Lysenko, A. Kozlova, and T. Cline,
on behalf of the Konus-Wind team, report:

Using Konus-Wind (KW) data, we have performed a search for a gamma-ray
transient around the time of the cosmic neutrino candidate IceCube-
160731A (http://gcn.gsfc.nasa.gov/notices_amon/6888376_128290.amon)

No triggered KW event happened from ~5 days before to ~1 day after
the IceCube event. The nearest KW triggers are GRB 160726A
(Frederiks et al, GCN 19733) and GRB 160802A (Kozlova et al, GCN 19767)

Using Konus-Wind waiting mode data in the interval Â±1000 s around the
IceCube trigger (July 31, 2016, 1:55:04 UTC), we estimate an upper
limit (90% conf.) on the 20 â€“ 1200 keV fluence to ~7.7x10^-7 erg/cm^2
for a burst with duration less than 2.944 s and with a typical
KW short GRB spectrum (an exponentially cut off power law with
alpha=-0.5 and Ep=500 keV, Svinkin et al. 2016).
For a typical long GRB spectrum (the Band function with alpha=-1,
beta=-2.5, and Ep=250 keV), the corresponding limiting peak flux
is ~5.8x10^-7 erg/cm^2/s (20 â€“ 1200 keV, 2.944 s scale).

A plot of the KW waiting mode data can be found at
http://www.ioffe.ru/LEA/IceCube/kw20160731_06904_bg.png


All the quoted values are preliminary.


GRB_name: GRB160802A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19778
SUBJECT: GRB 160802A: CALET Gamma-Ray Burst Monitor detection
DATE:    16/08/05 15:57:05 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

T. Tamura (Kanagawa U), A. Yoshida, T. Sakamoto, Y. Kawakubo, M. Moriyama,
Y. Yamada (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu (Kanagawa U), W. Ishizaki (ICRR),
M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long-duration GRB 160802A (Bissaldi et al., GCN Circ. 19754;
Panasyuk et al., GCN Circ. 19759; Kozlova et al., GCN Circ. 19767)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 6:13:28.85 on
2 August 2016.  The burst signal was seen by all CGBM instruments.

The light curve of the SGM shows two episodes.  The first episode
has a FRED-like structure with several pulses.  The emission starts
at T0 and ends at T+7 sec.  The second episode starts at T+17 sec,
peaks at T+18 sec and ends at T+22 sec.  The T90 duration measured by the
SGM data is 16.1 +- 0.1 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1154153496/

The CALET data used in this analysis are provided by the Waseda
CALET Operation Center located at the Waseda University.


GRB_name: GRB160804A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19779
SUBJECT: GRB 160804A: RATIR Optical and NIR Observations 
DATE:    16/08/05 17:40:09 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), Ori Fox (STScI), J.
Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara
(GSFC/STScI), 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),
Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (ASU), and
Vicki Toy (UMD) report:

We observed the field of GRB 160804A (Marshall et al., GCN Circular
19761) 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 2016/08 5.16 to
2016/08 5.27 UTC (26.33 to 29.04 hours after the BAT trigger), obtaining
a total of 1.78 hours exposure in the r and i bands and 0.75 hours
exposure in the Z, Y, J, and H bands.

We detect a source coincident with Swift/UVOT source (Breeveld et al.,
GCN Circular 19764) with the following magnitudes and 3-sigma upper
limit:

  r = 21.29 +/- 0.02
  i = 20.90 +/- 0.02
  Z = 21.12 +/- 0.19 
  Y = 21.04 +/- 0.29 
  J = 20.52 +/- 0.23 
  H > 20.51

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: GRB160802A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19782
SUBJECT: GRB160802A - Astrosat CZTI detection
DATE:    16/08/06 12:52:52 GMT
FROM:    Varun Bhalerao at IUCAA  <varunb@iucaa.in>

V. Bhalerao (IUCAA), V. Kumar (IUCAA), D. Bhattacharya (IUCAA), A. R. Rao (TIFR), S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:

Analysis of Astrosat data showed the CZTI detection of a very bright GRB160802A (Fermi-GBM detection: E. Bissaldi et al., GCN Circ. 19754).

The source was clearly detected in the 40-200 keV energy range. The light curve shows a complex structure, with the strongest peak at 06:13:30.90 UT, 0.27
seconds after Fermi Trigger at 06:13:29.63 UT and a peak count rate of 4270.0 counts/sec above the background (four quadrants summed together), with a total
of 91636 counts. The local mean background count rate was 310.0 counts/sec. Using cumulative rates, we measure a T90 of 16.8 secs.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb . CZTI is built by a TIFR-led consortium of
institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB160806A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19784
SUBJECT: IPN Triangulation of GRB 160806A
DATE:    16/08/09 12:59:49 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@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,

A. Kozlova, S. Golenetskii, R. Aptekar, 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,

S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer,
on behalf of the Swift-BAT team,

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, and

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

A short-duration GRB 160806A has been detected by Fermi (GBM),
Konus-Wind, INTEGRAL (SPI-ACS), Mars-Odyssey (HEND), and Swift (BAT)
at about 50460 s UT (14:01:00). The burst was outside the coded
field of view of the BAT.

We have triangulated it to a preliminary, 3 sigma error box whose
coordinates are:
 ---------------------------------------------
  RA(2000), deg                 Dec(2000), deg
 ---------------------------------------------
 Center:
  274.477 (18h 17m 54s) +10.607 (+10d 36' 25")
 Corners:
  275.105 (18h 20m 25s) +10.412 (+10d 24' 42")
  274.010 (18h 16m 02s) +11.481 (+11d 28' 52")
  273.846 (18h 15m 23s) +10.795 (+10d 47' 42")
  274.941 (18h 19m 46s)  +9.712 ( +9d 42' 45")
 ---------------------------------------------
The error box area is 3308 sq. arcmin, and its maximum
dimension is 1.99 deg (the minimum one is 36 arcmin).
The Sun distance was about 130 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB160806_T50460/IPN/

The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.


GRB_name: GRB160806A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19785
SUBJECT: Konus-Wind observation of GRB 160806A
DATE:    16/08/09 13:29:03 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks, 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 160806A
(IPN triangulation: Hurley et al., GCN 19784)
triggered Konus-Wind at T0=50460.639 s UT (14:01:00.639).

The burst light curve shows a single pulse
which starts at ~T0-0.5 s and has a total duration of ~1.0 s.
The emission is seen up to ~8 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB160806_T50460/

As observed by Konus-Wind, the burst
had a fluence of 1.16(-0.23,+0.49)x10^-6 erg/cm2,
and a 16-ms peak flux, measured from T0-0.026 s,
of 5.98(-3.46,+4.98)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The spectrum of the burst
(measured from T0 to T0+0.256 s)
is well fit in the 20 keV - 8 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -1.00 (-0.51,+0.80)
and Ep = 219 (-76,+395) keV (chi2 = 43/33 dof).
Fitting by a GRB (Band) model yields alpha = -0.63 (-0.65,+1.00),
Ep = 171 (-59,+154) keV, and an upper limit on the high energy
photon index: beta < -1.8 (chi2 = 40/32 dof)

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


GRB_name: GRB160806A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19786
SUBJECT: GRB 160806A: Fermi GBM observation
DATE:    16/08/09 15:54:06 GMT
FROM:    Peter Veres at UAH  <veresp@gmail.com>

P Veres (UAH) and C Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 14:00:58.42 UT on 6 August 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160806A (trigger 492184862 / 160806584)
which was also detected by the Konus-Wind
(Kozlova et al., GCN 19785) and located by the Interplanetary Network
(Hurley et al., GCN 19784). The GBM on-ground location is consistent with
the IPN position.

The angle from the Fermi LAT boresight at the GBM trigger time is 112
degrees.

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

The GBM light curve consists of a single symmetric pulse
with a duration (T90) of about 1.7 s (50-300 keV).
The time-averaged spectrum from T0 to T0+2 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.58 +/- 0.14 and
the cutoff energy, parameterized as Epeak, is 142 +/- 11 keV.

The event fluence (10-1000 keV) in this time interval is
(1.35 +/- 0.07)E-6 erg/cm^2. The 64 ms peak photon flux measured
starting from T0+0.13 s in the 10-1000 keV band
is 17.6 +/- 2.0 ph/s/cm^2.

A Band function fits the spectrum equally well with Epeak= 122 +/- 15 keV,
alpha = -0.41 +/- 0.20 and beta = -2.64 +/- 0.38.

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


GRB_name: GRB160806A
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19789
SUBJECT: INTEGRAL/SPI-ACS and IBIS_VETO search for prompt gamma-ray counterpart of IceCube-160806A
DATE:    16/08/10 16:40:10 GMT
FROM:    Volodymyr Savchenko at ISDC,U of Geneve  <savchenk@in2p3.fr>

V. Savchenko (APC, Paris, France) , C. Ferrigno (ISDC, University of 
Geneva, CH), P. Ubertini,  A. Bazzano, L. Natalucci (IAPS-Roma, Italy), 
S. Mereghetti (IASF-Milano, Italy),  P. Laurent (CEA, Saclay, France),  
E. Kuulkers (ESAC/ESA, Madrid, Spain)

Using INTEGRAL/SPI-ACS and INTEGRAL/IBIS VETO we have performed a search 
for prompt gamma-ray counterpart of cosmic neutrino candidate 
IceCube-160806A (Cowen 2016, GCN 19787).

At the time of the event (2016-08-06T12:21:33 UTC, hereafter T0), 
INTEGRAL IBIS was operating in the nominal mode. INTEGRAL/SPI was 
finishing the annealing cycle: at this stage of the procedure it has no 
effect on SPI-ACS.
The spacecraft was pointing in the direction of Norma Arm Region, and 
the neutrino localization was at 110 deg angle with respect to the 
pointing axis.
This orientation enables high response of both SPI-ACS and IBIS_VETO.

The nearest confirmed GRB (GRB160806A), was triggered by 
INTEGRAL/SPI-ACS at 2016-08-06 14:00:57, 1h 40m after the event. This 
GRB is also detected in the IBIS_VETO light curve.

SPI-ACS and  IBIS_VETO (bottom) light-curves around the time of the 
neutrino candidate event can be found at:

http://isdc.unige.ch/~savchenk/IceCube-160806A/

The count rate data around the event reveals variability, including 
smooth background instabilities as well as burst-like events.

Several burst-like excesses can be seen, most prominent ones at T0+50s, 
T-150s, T0-2000s, and T0-10000s.
Ratio of SPI-ACS to IBIS_VETO rates for these events is compatible with 
a gamma-ray source from the direction of IceCube-160806A.
However, we note that these flares are coincident with GOES proton 
background flares.

Although we can not exclude cosmic origin of some of these bursts, 
judging from long-lasting background instability near the region of 
interest, as well as the activity observed by GOES, we are inclined to 
conclude that these bursts are associated with background variability 
introduced by solar activity.

We estimate a 3-sigma upper limit on fluence in 75-2000 keV energy range 
in the interval Â±1000 s around the IceCube trigger of 3.3x10^-7 erg/cm^2 
for a burst with duration less than 1 s with a characteristic short GRB 
spectrum (an exponentially cut off power law with alpha=-0.5 and Ep=500 
keV).
For a typical long GRB spectrum (the Band function with alpha=-1, 
beta=-2.5, and Ep=250 keV), the corresponding limiting peak flux is 
~2.2x10^-7 erg/cm^2/s at 1 s time scale in 75-2000 keV energy range.

The SPI-ACS light curves, binned at 50 ms, are derived from 91 
independent detectors with different lower energy thresholds (mainly 
between 50 keV and 150 keV) and an upper threshold at about 100 MeV.

The IBIS_VETO light curves, binned at 8 s, are derived from 16 
independent detectors with lower energy thresholds near 80 keV and an 
upper threshold at about 50 MeV. Two groups of detector rates are 
recorded independently: bottom and lateral IBIS VETO. The response of 
the bottom IBIS VETO peaks in the direction opposite to satellite 
pointing axis, where the response of SPI-ACS is suppressed.

Due to solar angle constrains, INTEGRAL can not perform pointed 
observation of the location of IceCube-160806A until September 22, so no 
pointed follow-up will be scheduled.


GRB_name: GRB160804B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19792
SUBJECT: GRB 160804B: CALET Gamma-Ray Burst Monitor detection
DATE:    16/08/14 06:51:01 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

W. Ishizaki (ICRR), A. Yoshida, T. Sakamoto, Y. Kawakubo, M. Moriyama,
Y. Yamada (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The short-duration GRB 160804B (Fermi-GBM trigger #491977127)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 04:18:42.78
on 4 August 2016.  The burst signal was only seen by the SGM instrument.

The light curve of the SGM shows two short spikes.  The first peak starts
at T+0.4 s, peaks at T+0.45 s and ends at T+0.7 s.  The second spike
peaks at T+0.8 s with a duration of 0.1 s.  The T90 duration measured by
the SGM data is 0.41 +- 0.04 sec (100-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1154319406/

The CALET data used in this analysis are provided by the Waseda
CALET Operation Center located at the Waseda University.


GRB_name: GRB160814A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19793
SUBJECT: GRB 160814A: MAXI/GSC detection
DATE:    16/08/15 01:15:00 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

Y. Kawakubo (AGU), M. Serino (RIKEN), T. Sakamoto (AGU), S. Nakahira (JAXA),
H. Negoro (Nihon U.), S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara (JAXA),
Y. E. Nakagawa (JAMSTEC), T. Mihara, M. Sugizaki, W. Iwakiri, M. Shidatsu,
J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN), N. Kawai, N. Isobe, S. Sugita,
T. Yoshii, Y. Tachibana, Y. Ono, T. Fujiwara, S. Harita, Y. Muraki (Tokyo Tech),
A. Yoshida, Y. Kitaoka (AGU), H. Tsunemi, R. Shomura (Osaka U.), M. Nakajima,
K. Tanaka, T. Masumitsu, T. Kawase (Nihon U.), Y. Ueda, T. Kawamuro, T. Hori,
A. Tanimoto (Kyoto U.), Y. Tsuboi, Y. Nakamura, R. Sasaki (Chuo U.), M. Yamauchi,
K. Furuya (Miyazaki U.), K. Yamaoka (Nagoya U.)
report on behalf of the MAXI team:
  
The MAXI/GSC nova-alert system triggered a bright uncatalogued X-ray transient
source at 21:12:55 UT on 2016 August 14.  We obtain a rectangular error box for
the transient source at the center position of

  (R.A., Dec) = (136.074 deg, -20.960 deg) = (09 04 17, -20 57 36) (J2000)

with the following corners:

  (136.030, -21.250) deg = (09 04 07, -21 14 59) (J2000)
  (135.790, -21.121) deg = (09 03 09, -21 07 16) (J2000)
  (136.304, -20.423) deg = (09 05 12, -20 25 23) (J2000)
  (136.542, -20.552) deg = (09 06 10, -20 33 08) (J2000)

There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
  
The X-ray flux averaged over the scan was 413 +- 40 mCrab (4.0-10.0keV, 1 sigma error).
There was no significant excess flux in the previous transit at 19:40 and in the next
transit at 22:45 UT with an upper limit of 20 mCrab for each.


GRB_name: GRB160815A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19794
SUBJECT: GRB 160815A: Swift detection of a burst
DATE:    16/08/15 12:16:28 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

C. B. Markwardt (NASA/GSFC), P.A. Evans (U Leicester),
N. Gehrels (NASA/GSFC), J. A. Kennea (PSU),
F. E. Marshall (NASA/GSFC), B. Mingo (U Leicester),
K. L. Page (U Leicester), T. Sakamoto (AGU) and
B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team:

At 11:45:11 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160815A (trigger=708598).  Swift slewed immediately to the burst. 
The BAT location calculated from the downlinked detector histogram is 
RA, Dec 288.733, 84.282 which is 
   RA(J2000) = 19h 14m 56s
   Dec(J2000) = +84d 16m 55.2s
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  No BAT lightcurve is immediately available
due to a gap in TDRSS coverage. 

Using promptly downlinked data we find a fading, uncatalogued X-ray
source with an enhanced position: RA, Dec 288.5364, 84.3138 which is
equivalent to:
   RA(J2000)  = 19h 14m 08.73s
   Dec(J2000) = +84d 18' 49.8"
with an uncertainty of 2.0 arcseconds (radius, 90% containment). This
location is 134 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received; 
the latest position is available at http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (7.52 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 4.6
(+1.72/-1.57) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 250 seconds with the U filter starting
309 seconds after the BAT trigger. No credible afterglow candidate has been
found in the initial data products. Data from the 2.7'x2.7' sub-image are not
available at this time. The 8'x8' region for the list of sources generated
on-board covers none of the BAT error circle. No correction has been made for
extinction. 

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


GRB_name: GRB160815A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19795
SUBJECT: GRB 160815A: Swift/UVOT Afterglow Detection
DATE:    16/08/15 13:03:44 GMT
FROM:    Frank Marshall at GSFC  <femarsha@khamseen.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC) and C. B. Markwardt (NASA/GSFC) 
report on behalf of the Swift/UVOT team:

The Swift/UVOT has discovered an optical afterglow for 
GRB 160815A (Markwardt et al., GCN Circ. 19794) in
an exposure with the white filter.

The preliminary UVOT position is:
   RA  (J2000) =  19:14:09.63 = 288.5401 (deg.)
   Dec (J2000) =  +84:18:50.4  =  84.3140 (deg.)
with an estimated uncertainty of 1.0 arcsec. (radius, 90% confidence).

The preliminary magnitude 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

white           863        1013          150          19.1

The magnitude is not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.12 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB160815A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19796
SUBJECT: GRB 160815A: Enhanced Swift-XRT position
DATE:    16/08/15 16:24:47 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 1093 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 160815A, 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 = 288.54101, +84.31383 which is equivalent
to:

RA (J2000): 19h 14m 9.84s
Dec (J2000): +84d 18' 49.8"

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

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

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


GRB_name: GRB160815A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19797
SUBJECT: GRB 160815A: Fermi GBM detection/observation
DATE:    16/08/16 03:00:47 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007@uah.edu>

R. Hamburg (UAH)
reports on behalf of the Fermi GBM Team:

"At 11:45:11.64 UT on 15 August 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160815A (trigger 492954315 / 160815490)
which was also detected by the Swift/BAT
(Markwardt et al., GCN Circ. 19794)
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 37
degrees.

The GBM light curve consists of two peaks
with a duration (T90) of about 6.8 s (50-300 keV).
The time-averaged spectrum from T0-2.7 s to T0+5.5 s
is best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.68 +/- 0.12 and
the cutoff energy, parameterized as Epeak, is 71 +/- 4 keV.

The event fluence (10-1000 keV) in this time interval is
(1.64 +/- 0.06)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.9 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: GRB160815A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19798
SUBJECT: GRB 160815A: Swift-XRT refined Analysis
DATE:    16/08/16 06:08:13 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

V. D'Elia (ASDC), L.M. McCauley (PSU), J.A. Kennea (PSU), B. Sbarufatti
(INAF-OAB/PSU), P.A. Evans (U. Leicester), S.L. Gibson (U. Leicester),
J.P. Osborne (U. Leicester), A. D'Ai (INAF-IASFPA), A. Maselli 
(INAF-IASFPA) and C.B. Markwardt report on behalf of the Swift-XRT
team:

We have analysed 11 ks of XRT data for GRB 160815A (Markwardt et al.
GCN Circ. 19794), from 78 s to 34.8 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 Beardmore et al. (GCN Circ.
19796).

The light curve can be modelled with an initial power-law decay with an
index of alpha=6.1 (+1.9, -1.8), followed by a break at T+115 s to an
alpha of 0.88 (+/-0.03).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 3.25 (+0.31, -0.26). The
best-fitting absorption column is  3.2 (+0.7, -0.6) x 10^21 cm^-2, in
excess of the Galactic value of 7.5 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.90 (+/-0.15) and a
best-fitting absorption column of 2.6 (+0.7, -0.6) x 10^21 cm^-2. The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 3.8 x 10^-11 (5.3 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      2.6 (+0.7, -0.6) x 10^21 cm^-2
Galactic foreground: 7.5 x 10^20 cm^-2
Excess significance: 5.1 sigma
Photon index:      1.90 (+/-0.15)

If the light curve continues to decay with a power-law decay index of
0.88, 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 4.9 x
10^-13 (6.7 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/00708598.

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


GRB_name: GRB160815A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19799
SUBJECT: GRB 160815A: Swift-BAT refined analysis
DATE:    16/08/16 14:26:01 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

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), 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 160815A (trigger #708598)
(Markwardt, et al., GCN Circ. 19794).  The BAT ground-calculated position is
RA, Dec = 288.616, 84.298 deg which is
    RA(J2000)  =  19h 14m 27.8s
    Dec(J2000) = +84d 17' 53.9"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 41%.
  
The mask-weighted light curve shows several overlapping peaks starting
at T-7 sec and ending at T+11 sec.  Two main pulses peaks at T+0.3 sec
and T+2.5 sec.  T90 (15-350 keV) is 8.6 +- 1.8 sec (estimated error
including systematics).

The time-averaged spectrum from T-6.41 to T+5.20 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 0.96 +- 0.41,
and Epeak of 68 +- 16 keV (chi squared 48.11 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 1.4 +- 0.1 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T+2.14 sec in the 15-150 keV band is
4.7 +- 0.4 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.72 +- 0.09 (chi squared 59.91 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/708598/BA/


GRB_name: GRB160814A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19800
SUBJECT: Konus-Wind observation of GRB 160814A
DATE:    16/08/16 14:42:54 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

A.Kozlova, S. Golenetskii, R.Aptekar, D. Frederiks, P. Oleynik,
M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lysenko,
and T. Cline on behalf of the Konus-Wind team, report:

GRB 160814A, localized by MAXI/GSC (Kawakubo et al., GCN 19793)
was detected by Konus-Wind in the waiting mode.

The burst light curve shows a double-peaked structure,
started at ~T0(MAXI)-70.3 s with a total duration of ~ 71 s.

The K-W light curve of this burst is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB160814A/

As observed by Konus-Wind, the burst had a fluence of
5.5(-0.3,+0.7)x10^-6 erg/cm2 and a 2.944-s peak flux,
measured from ~T0(MAXI)-11.4 s, of 4.3(-0.6,+0.8)x10^-7 erg/cm2/s
(both in the 20 - 1000 keV energy range).

Modeling the K-W 3-channel time-integrated spectrum
(from ~T0(MAXI)-70.3 s to ~T0(MAXI)+0.4 s)
by a simple power-law model yields a power law
index of -2.2(-0.1,+0.1), chi2=1.3/1 dof.

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


GRB_name: GRB160815A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19801
SUBJECT: GRB 160815A: Swift/UVOT Detection
DATE:    16/08/16 21:53:24 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@swift.psu.edu>

S.J. LaPorte (PSU) and C. B. Markwardt (NASA/GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 160815A
90 s after the BAT trigger (Markwardt et al., GCN Circ. 19794). We detect a
fading source consistent with the XRT position (Beardmore et al. GCN Circ.
19796).

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           90             239       146     18.17+-0.14   
white          582            5549       402    >19.72   
v              632            5960       274    >17.99   
b              557            5344       254    >18.64   
u              301            6449       554    >18.85   
uvw1           681            6370       432    >18.67   
uvm2           656            6165       274    >18.64   
uvw2           607            5755       274    >18.70   


The magnitude is not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.12 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB160816A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19802
SUBJECT: GRB 160816A: Fermi-LAT detection 
DATE:    16/08/16 23:15:28 GMT
FROM:    Judith Racusin at GSFC  <judith.racusin@nasa.gov>

J. L. Racusin (NASA/GSFC), F. Dirirsa (U. Johannesburg), F. Longo (University and INFN, Trieste), 
J. McEnery (NASA/GSFC), and G. Vianello (Stanford) report on behalf of the Fermi-LAT team:

At 17:30:58 on August 16, 2016 Fermi-LAT detected high-energy emission from GRB 160816A, which 
was also detected by Fermi-GBM (trigger 493061460 / 160816730). 

The best LAT on-ground location is found to be:
RA, Dec = 322.45, 37.16 (J2000)
with an error radius of 0.13 deg (90% containment, statistical error only). 

This was 35 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 9.5 GeV 
event which is observed ~1100 seconds after the GBM trigger.

A Swift ToO request has been approved for this burst.

The Fermi-LAT point of contact for this burst is Francesco Longo (francesco.longo@trieste.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: GRB160816A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19803
SUBJECT: GRB 160816A: Swift ToO observations
DATE:    16/08/17 00:35:15 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 160816A. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020685

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: GRB160816A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19805
SUBJECT: GRB 160816A: MASTER inspection
DATE:    16/08/17 05:44:51 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

R. Rebolo, M. Serra, N. Lodieu, G. Israelian
The Instituto de Astrofisica de Canarias

K.Ivanov, O.Gres, N.M.Budnev, S.Yazev,
Irkutsk State University

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

A. Tlatov, V.Senik, D. Dormidontov, A.Parkhomenko
Kislovodsk Solar Station of the Pulkovo Observatory

V.Yurkov, Yu.Sergienko, A.Gabovich
Blagoveschensk Educational State University, Blagoveschensk

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

R.Podesta, C.Mallamaci, C.Lopez, F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA)

MASTER-IAC robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in Teide observatory was pointed to the Fermi LAT
GRB160816A  924 sec after notice time at 2016-08-16 22:57:12 UT 
(NOTICE_DATE:Tue 16  Aug 16 22:42:36 UT)  and 19665 sec after the trigger 
time(the delay in 15min was from the inspection of previous FermiGBM 
alert and late notice time).

  On our first  180s exposures we haven't found optical transient  within
  LAT error-box (RA, Dec = 322.45, 37.16 (J2000) r=0.13).

There is a disc galaxy (unknown in NED) inside LAT error-box at the 
position 21h 29m 23.16s +37d 05m 54.9s - possible host galaxy for GRB.

The 5-sigma upper limit has been about 19.7 mag
The message may be cited.


GRB_name: GRB160816A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19806
SUBJECT: GRB 160816A: Swift-XRT afterglow detection
DATE:    16/08/17 07:10:35 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU),
S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester), A. D'Ai (INAF-IASFPA), A. Maselli  (INAF-IASFPA), A.
Melandri (INAF-OAB) 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 160816A (Racusin et al. GCN Circ. 19802),
collecting 1.6 ks of Photon Counting (PC) mode data between T0+25.2 ks
and T0+31.8 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=322.4108, +37.1324 which is equivalent to:

RA (J2000): 21:29:38.59
Dec(J2000): +37:07:56.6

with an uncertainty of 3.8 arcsec (radius, 90% confidence).  This
position is 3.8 arcmin from the Fermi/LAT position.  The light curve is
consistent with a constant source of mean count rate 7.8e-02 ct/sec. A
power-law fit gives an index of 1.5 (+1.8, -1.7).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.7 (+0.6, -0.3). The
best-fitting absorption column is  2.97 (+3.55, -0.16) x 10^21 cm^-2,
consistent with the Galactic value of 2.8 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 (5.8 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      2.97 (+3.55, -0.16) x 10^21 cm^-2
Galactic foreground: 2.8 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.7 (+0.6, -0.3)

The results of the XRT-team automatic analysis of the likely afterglow
are at http://www.swift.ac.uk/ToO_GRBs/00020685/index_1.php.
The results of the full analysis of the XRT observations are available
at http://www.swift.ac.uk/ToO_GRBs/00020685.

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


GRB_name: GRB160815A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19807
SUBJECT: GRB 160815A:  GWAC-F60A upper limit
DATE:    16/08/17 07:52:18 GMT
FROM:    L.P. Xin at NAOC  <xlp@bao.ac.cn>

L. P. Xin,   Y. J. Xiao,   X. M. Meng,   J. Y. Wei,   E. W. Liang,  X. G. Wang,
Y. G. Yang,  X. M. Lu,  L. Huang,   X. H. Han ,  H. B. Cai,   Y. L. Qiu,
J. Wang,   C. Wu,   J. S. Deng and H. L. Li  report:
 
We  observed  GRB 160815A (Markwardt et al. GCN 19794)  with
GWAC-F60A 60cm optical telescope at 17:10:08 UT,  Aug. 15th 2016, 
about 5.41 hours after the burst. 

The optical afterglow (Marshall et al., GCN 19795; LaPorte et al., GCN 19081) 
was  not detected in our 20*300 sec stacked R-band  images  down to the 3 sigma 
limit  of  about 19.7 mag at the mid time  of 6.42 hours after the burst.
The brightness was calibrated by  USNO B1.0 stars.
 
GWAC-F60A is operated by Guangxi university and NAOC, CAS, 
at Xinglong observatory, China.

The message may be cited.


GRB_name: GRB160816A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19808
SUBJECT: GRB 160816A: LCOGT-FTN optical candidate
DATE:    16/08/17 08:17:39 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi (U. Ferrara), S. Kobayashi, I.A. Steele (LJMU), C.G. Mundell 
(U. Bath), A. Gomboc (U. Nova Gorica) on behalf of a large collaboration 
report:

The 2-m LCOGT Faulkes Telescope North began observing Fermi-LAT GRB 
160816A (Racusin et al., GCN 19802) on August 17, 07:23:08 UT (13.9 
hours after the burst trigger). Inside the Swift-XRT error circle of the 
X-ray afterglow candidate (Kennea et al., GCN 19806) we find an 
uncatalogued source at the following position:

RA(J2000)=  21:29:38.58
Dec(J2000)= +37:07:58.7

with an uncertainty of 1.0 arcsec and r~21.0 +- 0.2 mag (AB).


GRB_name: GRB160816A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19809
SUBJECT: GRB 160816A: RATIR Optical and NIR Observations
DATE:    16/08/17 09:26:10 GMT
FROM:    Eleonora Troja at GSFC  <eleonora.troja@nasa.gov>

Eleonora Troja (GSFC), Alan M. Watson (UNAM), Nat Butler (ASU),
Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G.
Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC),
Josh Bloom (UCB), Antonino Cucchiara (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), Harvey Moseley (GSFC), John Capone (UMD), V. Zach
Golkhou (ASU), and Vicki Toy (UMD) report:

We observed the field of the Fermi GRB 160816A (Mailyan, et al.,
GCN 19804; Racusin et al. 19802) 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 2017-08-17 06:15 to 07:44 UTC (12.8 to 14.2 hours after
the GBM trigger), obtaining a total of 0.71 hours exposure in the r
and i bands and 0.30 hours exposure in the Z, Y, J, and H bands.

For a source within the Swift/XRT error circle (Kennea et al., GCN 19806),
in comparison with the USNO-B1 and 2MASS catalogs, we obtain the
following detections:

r = 21.05 +/- 0.05
i = 20.79 +/- 0.04
Z = 20.61 +/- 0.07
Y = 20.32 +/- 0.08
J = 20.16 +/- 0.09
H = 19.95 +/- 0.10

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB. The source position is
RA,Dec(J2000)=21:29:38.549,+37:07:58.79 with an uncertainty of 0.5 arcsec.
Our position is consistent with the candidate reported from Guidorzi,
et al. (GCN 19808).

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

Further observations are on-going.


GRB_name: GRB160816A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19810
SUBJECT: Konus-Wind observation of GRB 160816A
DATE:    16/08/17 13:32:53 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, P. Oleynik,
M. Ulanov,  A. Tsvetkova, A. Lysenko, A. Kozlova, and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration, very intense, GRB 160816A
(Fermi LAT detection: Racusin et al., GCN Circ. 19802;
Fermi GBM observation: Mailyan and Meegan, GCN Circ. 19804)
triggered Konus-Wind at T0=63061.653 s UT (17:31:01.653).

The burst light curve shows a multipeaked structure
started at ~T0 with a total duration of ~14 s.
The emission is seen up to 3 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB160816_T63061/

As observed by Konus-Wind, the burst
had a fluence of 3.16(-0.10,+0.11)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+8.032 s,
of 1.63(-0.16,+0.16)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+19.712 s)
is best fit in the 20 keV - 3 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -0.81(-0.06,+0.06)
and Ep = 239(-11,+12) keV (chi2 = 51/68 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -3.0
(chi2 = 49/67 dof)

The spectrum near the maximum count rate
(measured from T0+2.304 to T0+8.448 s)
is best fit in the 20 keV - 3 MeV range
by a power law with exponential cutoff model
with  alpha = -0.89(-0.08,+0.09)
and Ep = 244(-18,+20) keV (chi2 = 66/68 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -3.2
(chi2 = 66/67 dof)

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


GRB_name: GRB160714A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19811
SUBJECT: GRB 160714A: 15 GHz upper limits from AMI
DATE:    16/08/17 13:55:38 GMT
FROM:    Kunal Mooley at Oxford U  <kunal.mooley@physics.ox.ac.uk>

K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson 
(Curtin), T. Cantwell (Manchester), C. Rumsey, D. Titterington, S. 
Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), 
K. Grainge, A. Scaife (Manchester)

The AMI Large Array robotically triggered on the Swift alert for GRB 
160714A (Siegel et al., GCN 19697) as part of the 4pisky program, and 
subsequent follow up observations were obtained up to 10 days 
post-burst. Our observations at 15 GHz on 2016 Jul 14.65, Jul 17.85, and 
Jul 21.85 (UT) do not reveal any variable radio source within the BAT 
error circle (Palmer et al., GCN 19705), with 3sigma upper limits of 150 
uJy, 213 uJy, and 132 uJy respectively.

We thank the AMI staff for scheduling these observations. The AMI-GRB 
database is a log of all GRB follow up observations with the AMI, and is 
available at http://4pisky.org/ami-grb/.


GRB_name: GRB160801A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19812
SUBJECT: GRB 160801A: 15 GHz upper limits from AMI
DATE:    16/08/17 13:56:45 GMT
FROM:    Kunal Mooley at Oxford U  <kunal.mooley@physics.ox.ac.uk>

K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson 
(Curtin), T. Cantwell (Manchester), C. Rumsey, D. Titterington, S. 
Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), 
K. Grainge, A. Scaife (Manchester)

The AMI Large Array robotically triggered on the Swift alert for GRB 
160801A (D'Elia et al., GCN 19744) as part of the 4pisky program, and 
subsequent follow up observations were obtained up to 10 days 
post-burst. Our observations at 15 GHz on 2016 Aug 02.75, Aug 04.75, and 
Aug 08.73 (UT) do not reveal any radio source at the XRT location (Goad 
et al., GCN 19746), with 3sigma upper limits of 147 uJy, 123 uJy, and 
126 uJy respectively.

We thank the AMI staff for scheduling these observations. The AMI-GRB 
database is a log of all GRB follow up observations with the AMI, and is 
available at http://4pisky.org/ami-grb/.


GRB_name: GRB160804A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19813
SUBJECT: GRB 160804A: 15 GHz detections and upper limit from AMI
DATE:    16/08/17 14:00:08 GMT
FROM:    Kunal Mooley at Oxford U  <kunal.mooley@physics.ox.ac.uk>

K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson 
(Curtin), T. Cantwell (Manchester), C. Rumsey, D. Titterington, S. H. 
Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), 
K. Grainge, A. Scaife (Manchester)

The AMI Large Array triggered on the Swift alert for GRB 160804A 
(Marshall et al., GCN 19761) as part of the 4pisky program, and 
subsequent follow up observations were obtained up to 12 days 
post-burst. Our observations at 15 GHz on 2016 Aug 04.85, Aug 05.75, Aug 
07.75, Aug 11.75, and Aug 16.67 (UT) reveal a transient radio source at 
the XRT location (Osborne et al., GCN 19762), with flux densities of 
<141 uJy (3sigma), 189+/-46 uJy, 583+/-40 uJy, 292+/-34 uJy, and 
168+/-38 uJy respectively.

We thank the AMI staff for scheduling these observations. The AMI-GRB 
database is a log of all GRB follow up observations with the AMI, and is 
available at http://4pisky.org/ami-grb/.


GRB_name: GRB160816A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19814
SUBJECT: GRB 160816A: IPN annulus
DATE:    16/08/17 18:17:28 GMT
FROM:    Kevin Hurley at UCBerkeley/SSL  <khurley@ssl.berkeley.edu>

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,

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

S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova, 
D. Svinkin, and T. Cline, on behalf of the Konus-Wind team, and

V. Connaughton, M. S. Briggs, C. Meegan, V. Pelassa, and A. Goldstein, 
on behalf of the Fermi GBM team, report:

GRB 160816A has been observed by Konus-Wind (GCN 19810), Fermi GBM and LAT
(GCN 19804, GCN 19802), and Mars Odyssey-HEND, so far.  We have triangulated
it to a preliminary annulus centered at RA, Dec (2000)=63.3328, 24.0531 degrees,
with radius 83.8027 +/- 0.1087 degrees (3 sigma).  The center line of the annulus passes 0.0086 degrees
from the Swift XRT source (GCN 19806), supporting the conclusion that this source
is the GRB afterglow.  A map has been posted at ssl.berkeley.edu/ipn3/160816A.


GRB_name: GRB160816A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19815
SUBJECT: GRB 160816A: Swift/UVOT Detection
DATE:    16/08/17 19:29:32 GMT
FROM:    Paul Kuin at MSSL  <npkuin@gmail.com>

Paul Kuin (UCL/MSSL), D. Malesani (DARK/NBI and DTU Space), Frank
Marshall (GSFC) and Lea Hagen (PSU) report on behalf of the Swift/UVOT
team:

The Swift/UVOT began settled observations of the field of the Fermi/LAT-
detected GRB 160816A 25222 s after the LAT trigger (Racusin et al. GCN
Circ. 19802). A source consistent with the XRT position (Kennea et al.
GCN Circ. 19806) and the LCOGT Faulkes Telescope North position (Guidorzi
et al., GCN Circ. 19808) is detected in the initial UVOT exposures at the
same position as reported by RATIR (Troja et al, GCN. Circ. 19809).

Preliminary detections and 3-sigma upper limit 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            27601        43846          879         21.48 +/- 0.22
v                27661        27703           41        >17.9
u                25222        37523         2287         21.37 +/- 0.31

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.25 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB160814A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19816
SUBJECT: GRB 160814A: CALET Gamma-Ray Burst Monitor detection
DATE:    16/08/17 23:23:59 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

M. L. Cherry (LSU), A. Yoshida, T. Sakamoto, Y. Kawakubo, M. Moriyama,
Y. Yamada (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long-duration GRB 160814A (Kawakubo et al., GCN Circ. 19793;
Kozlova et al., GCN Circ. 19800) triggered the CALET Gamma-ray Burst Monitor
(CGBM) at 21:12:42.39 on 14 August 2016.  The burst signal was seen by
all CGBM instruments.  Because of a problem in one of the ground alert processing
computer, the GCN notice was not distributed automatically for this event.

The light curve of the SGM shows two episodes.  The first weak episode
starts from T-60 sec, peaks at T-55 sec and ends at T-50 sec.  The
second episode starts from T+1 sec, peaks at T+3 sec and ends at T+12 sec.
The T90 duration measured by the SGM data is 10 +- 1 sec (40-230 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1155244227/

The CALET data used in this analysis are provided by the Waseda
CALET Operation Center located at the Waseda University.


GRB_name: GRB160816A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19818
SUBJECT: GRB 160816A iTelescope observation
DATE:    16/08/18 03:00:05 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

Y. Kitaoka, T. Sakamoto, A. Yoshida (AGU)

We observed the field of GRB 160816A detected by Fermi (Racusin et al.,
GCN Circ. 19802) with the iTelescope.Net (http://www.itelescope.net) T7
(17" Plane Wave) telescope located at the AstroCamp Observatory (Nerpio, Spain).
15 images of 60 sec exposures were taken in the R filter starting from
August 16 22:50:57 (UT) about 5.9 hours after the trigger and stopped on
August 16 23:26:36 (UT).  We do not detect the optical afterglow both in the
individual images and the stacked image at the X-ray afterglow position
(Kennea et al., GCN Circ. 19806).  The estimated five sigma upper limit
of the combined image (total exposure of 900 sec) is ~18.3 using the
USNO-B1 catalog.


GRB_name: GRB160816A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19819
SUBJECT: GRB 160816A: confirmed fading with the LT
DATE:    16/08/18 12:23:22 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi (U. Ferrara), S. Kobayashi, I.A. Steele (LJMU), C.G. Mundell 
(U. Bath), A. Gomboc (U. Nova Gorica), N. Tanvir (U. Leicester) on 
behalf of a large collaboration report:

The 2-m Liverpool Telescope observed GRB 160816A from August 17, 23:29 
UT to August 18, 02:44 UT with a total net exposure of 600 s in both 
SDSS-R and SDSS-I filters. The optical afterglow candidate (Guidorzi et 
al. GCN 19808; Troja et al. GCN 19809; Kuin et al. GCN 19815) has faded 
to r=21.8 +- 0.2 mag at 1.3 days post burst, compatibly with an average 
power-law decay index alpha~1.


GRB_name: GRB160816A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19820
SUBJECT: GRB 160816A: RATIR Optical and NIR Afterglow Confirmation
DATE:    16/08/18 12:35:04 GMT
FROM:    Eleonora Troja at GSFC  <eleonora.troja@nasa.gov>

Eleonora Troja (GSFC), Nat Butler (ASU), Alan M. Watson (UNAM),
Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G.
Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC),
Josh Bloom (UCB), Antonino Cucchiara (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), Harvey Moseley (GSFC), John
Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:

We observed the field of GRB 160816A (Mailyan, et al., GCN 19804;
Racusin, et al., GCN 19802) 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 2016/08 18.17 to 2016/08 18.47 UTC (1.44 to
1.72 days after the GBM trigger), obtaining a total of 2.47 hours
exposure in the r and i bands and 1.03 hours exposure in the Z,
Y, J, and H bands.

For the source reported in Troja, et al. (GCN 19809), in comparison
with the USNO-B1 and 2MASS catalogs, we obtain the following
detections and upper limit (3-sigma):


    r    22.74 +/- 0.15
    i    22.40 +/- 0.12
    Z    22.19 +/- 0.19
    Y    22.18 +/- 0.25
    J    > 22.32
    H    21.20 +/- 0.18

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

The source intensity decreased significantly between our two epochs,
corresponding to fading with power-law index alpha~-1.3 referenced to
the burst trigger. This confirms that the candidate reported by
Guidorzi, et al. (GCN 19808) and Troja et al. (GCN 19809) is the GRB
afterglow.

Deep imaging of the GRB location reveals additional optical sources
within the XRT localization (Kennea et al., GCN 19806), however none of
them have faded.

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


GRB_name: GRB160816A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19821
SUBJECT: GRB 160816A: MASTER OT early detection on coaded images
DATE:    16/08/18 16:25:19 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

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

R. Rebolo, M. Serra, N. Lodieu, G. Israelian
The Instituto de Astrofisica de Canarias

K.Ivanov, O.Gres, N.M.Budnev, S.Yazev,
Irkutsk State University

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

A. Tlatov, V.Senik, D. Dormidontov, A.Parkhomenko
Kislovodsk Solar Station of the Pulkovo Observatory

V.Yurkov, Yu.Sergienko, A.Gabovich
Blagoveschensk Educational State University, Blagoveschensk

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

R.Podesta, C.Mallamaci, C.Lopez, F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA)

MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in IAC was pointed to the  GRB160816.73 24 sec after notice time 
and 18726 sec after trigger time at 2016-08-16 22:43:04 UT. (We corrected 
start  exposition time which published in  previouse MASTER circular 
(Lipunov et al., GCN 19805). We reducted coadded images and found OT.

We see  OT on coadded images inside SWIFT XRT (Kennea et al., GCN19806) at 
LCOGT position (Guidorzi  et al., GCN 19808, Kuin et al., GCN 19815) on two 
tubes with unfiltered magnitude calibrated by USNO B1 stars ( m = 
0.2B+0.8R ):


m_OT=20.5  (+0.5 -0.2) at mean exposition time  2016-08-16 23:05:53, 
20095 sec (5.58 hours)  after GBM trigger time. T_start =18762sec, 
T_end=21464 
after 
trigger. The total exposition = 1800 sec.

The images is available at
http://observ.pereplet.ru/images/GRB160816AMASTER.jpg

The message may be cited.


GRB_name: GRB160815A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19823
SUBJECT: GRB 160815A: CALET Gamma-Ray Burst Monitor detection
DATE:    16/08/19 07:57:27 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

S. Ricciarini (U of Florence), A. Yoshida, T. Sakamoto, Y. Kawakubo, M. Moriyama,
Y. Yamada (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU), P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long-duration GRB 160815A (Markwardt et al., GCN Circ. 19794;
Hamburg et al., GCN Circ. 19797) triggered the CALET Gamma-ray Burst Monitor
(CGBM) at 11:45:10.86 on 15 August 2016.  The burst signal was seen by
the SGM instrument.  Because of a problem in one of the ground alert processing
computer, the GCN notice was not distributed automatically for this event.

The light curve of the SGM shows several two peaks.  The whole emission starts
at T0 and ends at T+4 sec.  The two spikes peak at T+0.5 sec and T+3 sec.
The T90 duration measured by the SGM data is 3.6 +- 0.6 sec (40-100 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1155296575/

The CALET data used in this analysis are provided by the Waseda
CALET Operation Center located at the Waseda University.


GRB_name: GRB160816A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19824
SUBJECT: GRB 160816A: Further RATIR Optical and NIR Observations
DATE:    16/08/19 14:22:23 GMT
FROM:    Eleonora Troja at GSFC  <eleonora.troja@nasa.gov>

Eleonora Troja (GSFC), Nat Butler (ASU), Alan M. Watson (UNAM),
Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G.
Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC),
Josh Bloom (UCB), Antonino Cucchiara (UVI), 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), Harvey Moseley (GSFC), John
Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:

We observed the field of the Fermi GRB 160816A (Mailyan, et al.,
GCN 19804) 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 2016/08 19.16 to 2016/08 19.50 UTC (2.43 to 2.77 days after
the GBM trigger), obtaining a total of 5.58 hours exposure in the
r and i bands and 4.56 hours exposure in the Z and J bands.

For the source reported in Troja, et al. (GCN 19809), in comparison
with the USNO-B1 and 2MASS catalogs, we obtain the  following
detections:

   r    23.45 +/- 0.15
   i    23.18 +/- 0.12
   Z    22.64 +/- 0.12
   J    22.37 +/- 0.16

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: GRB160816A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19825
SUBJECT: GRB 160816A: ISON/UAFO optical observations
DATE:    16/08/19 15:34:50 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI),  E. Chornaya (UAFO, ISON), A. Matkin (UAFO), I. 
Molotov (KIAM), A. Pozanenko (IKI) report on behalf of  larger GRB 
follow-up collaboration:

We observed the field of GRB 160816A  (Racusin et al., GCN 19802; 
Mailyan et al., GCN 19804)   with SANTEL-650 (0.65m)  telescope  of 
UAFO/ISON-Ussuriysk observatory. We obtained several unfiltered images 
starting on  August 17 (UT) 11:47:34.  We detected  optical afterglow 
(Guidorzi et al. GCN 19808; Troja et al. GCN 19809). Preliminary 
photometry of a combined image is following

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

2016-08-17 11:47:34 0.80873  CR      275*20 20.90  0.22  21.5

Photometry is based on nearby USNO-B1.0 stars
USNO-B1.0_id    R2
1271-0576219    17.27
1271-0576200    17.52
1271-0576190    18.12
1271-0576101    17.00
1271-0576308    17.05


GRB_name: GRB160819A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19826
SUBJECT: GRB 160819A: Fermi GBM detection
DATE:    16/08/20 03:32:34 GMT
FROM:    Peter Veres at UAH  <veresp@gmail.com>

P Veres (UAH) and C Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 20:27:35.49 UT on 19 August 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160819A (trigger 493331259 / 160819852).

The on-ground calculated location, using the GBM trigger
data, is RA = 118.91, DEC = -20.64 (J2000 degrees,
equivalent to 7 h 56 m, -20 d 38 '), with an uncertainty
of 1.13 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which we have characterized as a core-plus-tail model, with 90% of
GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg
systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).

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

The trigger resulted in an Autonomous Repoint Request (ARR)
by the GBM Flight Software owing to the high peak flux
of the GRB. This ARR was accepted and the spacecraft slewed to the GBM
in-flight
location. The initial angle from the Fermi LAT boresight to
the GBM ground location is 66 degrees.

The GBM light curve consists of multiple overlapping pulses
with a duration (T90) of about 23.8 s (50-300 keV).
The time-averaged spectrum from T0+18.4s to T0+41 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.45 +/- 0.04 and
the cutoff energy, parameterized as Epeak, is 109.9 +/- 5.4 keV.

The event fluence (10-1000 keV) in this time interval is
(2.14+/- 0.05)E-5 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+28.9 s in the 10-1000 keV band
is 17.1 +/- 0.4 ph/s/cm^2.

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


GRB_name: GRB160819A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19827
SUBJECT: BAT detection and localization of GRB 160819A
DATE:    16/08/20 23:08:58 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
and A. Y. Lien (GSFC/UMBC) report on behalf of the Swift Team:

At 20:27:30.40 UT on 2016-08-19, the Swift Burst Alert Telescope (BAT)
detected GRB 160819A, which was also detected by Fermi/GBM and
INTEGRAL SPI-ACS (Veres et al., GCN Circ. 19826). BAT was slewing to
a pre-planned target at that time, so it did not trigger on the burst.

However, ground analysis using the slew data fromT+27 to T+106 sec
reveals the GRB location of RA, Dec = 114.139, -22.347 deg, which is
  RA(J2000)  =  07h 36m 33.3s
  Dec(J2000) = -22d -20' -50.2"
with an uncertainty of 3.0 arcmin, (radius, sys+stat, 90% containment).
This position is 4.76 deg from the one reported by Fermi GBM, which is
consistent with the reported GBM error circle (Veres et al., GCN Circ. 19826).

The mask-weighted light curve shows a double-peaked structure that starts
before the beginning of the available event data, and ends at ~ T+70 s. The
two peaks occur at ~T+47 s and ~T+53 s, respectively.

The time-averaged spectrum from T+26.6 to T+73.6 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.70 +- 0.05.  The fluence in the 15-150 keV band is (7.76 +/- 0.23) x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+46.70 sec in the 15-150 keV band
is 12.1 +- 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/00086022006/BA/


GRB_name: GRB160816A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19829
SUBJECT: GRB 160816A: TSHAO optical observations
DATE:    16/08/21 13:37:01 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI), I. Reva (Fesenkov Astrophysical Institute), A. Kusakin 
(Fesenkov Astrophysical Institute),  A. Volnova (IKI), A. Pozanenko 
(IKI) report on behalf of larger GRB follow-up collaboration:

We observed the field of 160816A  (Racusin et al., GCN 19802; Mailyan et 
al., GCN 19804)  with Zeiss-1000 (East) 1-m telescope of Tien Shan 
Astronomical Observatory. We obtained several images in R filter 
starting on August 17 and 18.  We detected  optical afterglow (Guidorzi 
et al. GCN 19808; Troja et al. GCN 19809) on Aug. 17 and obtained upper 
limit on Aug. 18. Preliminary photometry of a combined image is following

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

2016-08-17 21:32:28 1.19553  R      105*30 21.70  0.20  21.9
2016-08-18 19:11:47 2.11663  R      148*30 n/d    n/d   22.1


Photometry is based on nearby USNO-B1.0 stars
USNO-B1.0_id    R2
1271-0576219    17.27
1271-0576200    17.52
1271-0576190    18.12
1271-0576101    17.00


GRB_name: GRB160821A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19830
SUBJECT: GRB 160821A: Swift detection of a bright burst
DATE:    16/08/21 20:45:20 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

M. H. Siegel (PSU), S. D. Barthelmy (GSFC), A. Y. Lien (GSFC/UMBC),
D. Malesani (DARK/NBI), K. L. Page (U Leicester) and D. M. Palmer (LANL)
report on behalf of the Swift Team:

At 20:34:30 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160821A (trigger=709351).  Swift did not slew due to
Sun observing constraint.  The BAT on-board calculated location is 
RA, Dec 171.248, +42.343, which is 
   RA(J2000)  =  11h 24m 59s
   Dec(J2000) = +42d 20' 35"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows several small peaks and then
a large peak at ~T+130 sec with a total duration of at least 160 sec. 
The peak count rate was ~24,000 counts/sec (15-350 keV), at ~138 sec after the trigger. 

Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 10:53 UT on 2016 September 29. There will thus be no XRT
or UVOT data for this trigger before this time. 

Burst Advocate for this burst is M. H. Siegel (siegel 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.)

[GCN OPS NOTE(21aug16): Per SDB, DM was added to the author list.]


GRB_name: GRB160821A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19831
SUBJECT: GRB 160821A: Fermi-LAT detection of a bright burst
DATE:    16/08/21 21:40:46 GMT
FROM:    Julie McEnery at NASA/GSFC  <julie.e.mcenery@nasa.gov>

**J. McEnery, J. Racusin (NASA/GSFC) and Francesco Longo 
(INFN/Trieste) report on
behalf of the Fermi-LAT team:

At 20:36:44.33 on August 21, 2016, Fermi-LAT triggered
on high-energy emission from GRB 160821A, also detected by GBM (trigger 
493504474/
GRB160821857), and Swift-BAT (Siegel et al., GCN 19830).

The onboard location is

RA, Dec = 172.5, 43.0 (J2000)

with an error radius of 0.5 deg (90% containment, systematic error 
only).  This was 17 deg
from the LAT boresight at the time of the trigger.

Onboard LAT GRB detections are relatively rare, and imply that this GRB 
is exceptionally
bright at high energy gamma-rays. We strongly encourage follow-up 
observations.

The Fermi-LAT point of contact for this burst is Francesco Longo
(francesco.longo@trieste.infn.it <mailto:francesco.longo@trieste.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: GRB160821A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19832
SUBJECT: GRB 160821A: TAROT Calern observatory optical detection
DATE:    16/08/21 22:38:49 GMT
FROM:    Bruce Gendre at ASDC  <bruce.gendre@gmail.com>

Gendre B. (UVI - Etelman Obs.), Klotz A., Turpin D., Atteia J.L. 
(CNRS-OMP-IRAP), Boer, M., Laugier, R. (CNRS-ARTEMIS) report:

We imaged the field of GRB 160821A detected by SWIFT
(trigger 709351) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.

The observations started 29.31min after the GRB trigger.
The elevation of the field decreased from
10 degrees above horizon and weather conditions
were fair.

We detect a new fading source in the error box given by SWIFT (Siegel et 
al., GCNC 19830) at the following position (+/- 3 arcsec):

RA(J2000) = 11h 25m 01.6s
DEC(J2000) +42d 20' 05"

OT was R~15.4 at 29.31min after GRB. Due to the brightness of the event, 
we encourage any follow-up.

Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.

N.B. Galactic coordinates are lon=166.5065 lat=+66.7370
and the galactic extinction in R band is 0.1 magnitudes
estimated from D. Schlegel et al. 1998ApJ...500..525S.

This message may be cited.


GRB_name: GRB160821B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19833
SUBJECT: GRB 160821B: Swift detection of a short burst
DATE:    16/08/21 22:43:52 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

M. H. Siegel (PSU), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),
A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC),
D. M. Palmer (LANL) and B. Sbarufatti (INAF-OAB/PSU) report on behalf
of the Swift Team:

At 22:29:13 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160821B (trigger=709357).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 279.987, +62.393, which is 
   RA(J2000)  =  18h 39m 57s
   Dec(J2000) = +62d 23' 34"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a single spike
structure with a duration of about 0.5 sec.  The peak count rate
was ~5000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 22:30:19.1 UT, 66.0 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source with an enhanced position: RA, Dec
279.9780, 62.3920 which is equivalent to:
   RA(J2000)  = 18h 39m 54.71s
   Dec(J2000) = +62d 23' 31.3"
with an uncertainty of 2.5 arcseconds (radius, 90% containment). This
location is 15 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 5.75
x 10^20 cm^-2 (Willingale et al. 2013). 

The initial flux in the 2.5 s image was 1.45e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 76 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' covers 100% of
the XRT error region. The typical 3-sigma upper limit has
been about 19.6 mag. No correction has been made
for the expected extinction corresponding to E(B-V) of 0.05. 

Burst Advocate for this burst is M. H. Siegel (siegel 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: GRB160821B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19834
SUBJECT: GRB 160821B: NOT optical afterglow candidate
DATE:    16/08/22 02:30:07 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

D. Xu (NAOC/CAS), D. Malesani (DARK/NBI and DTU Space), A. de Ugarte 
Postigo (IAA-CSIC, DARK/NBI), E. Gafton, I. Rivero Losada (NOT) report 
on behalf of a larger collaboration:

We observed the field of the short GRB 160821B (Siegel et al., GCN 
19833) using the 2.56-m Nordic Optical Telescope (NOT) equipped with the 
ALFOSC camera. Observations started at 23:02:07 UT on 2016-08-21 (i.e., 
0.548 hr after the burst), and 12 x 300s SDSS r-band frames were 
obtained under variable cirrus.

We detected an uncatalogued point source at coordinates:

R.A. = 18:39:54.56
Dec. = +62:23:30.5

with an uncertainty radius of ~0.2 arcsec, which is within the XRT error 
circle reported in Siegel et al. (GCN 19833). This source had 
R=22.6+/-0.1 mag at 0.95 hr after the burst, calibrated against the star 
of R = 17.6 at RA = 18:39:57.59, Dec = +62:22:31.7 in the USNO B1 catalogue.

We also note the presence of a bright, extended, nearby galaxy, 5.5" 
away, with a magnitude R ~ 19.2, which is a candidate host galaxy of GRB 
160821B.

Lacking variability, we cannot confirm whether the source we identified 
is the afterglow of GRB 160821B. Further observations are encouraged.


GRB_name: GRB160821A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19835
SUBJECT: GRB 160821A: Fermi GBM Detection
DATE:    16/08/22 04:13:58 GMT
FROM:    Matthew Stanbro at UAH/Fermi  <mcs0001@uah.edu>

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

"At 20:34:30.04 UT on 21 August 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160821A (trigger 493504474 / 160821857), which
was also detected by the Swift/BAT (Siegel et al. 2016, GCN 19830) and
by the LAT (McEnery et al. 2016, GCN 19831).
The GBM on-ground location is consistent with the Swift position.

The GBM light curve shows/consists of several episodes and
a bright burst with a duration (T90) of about 43 s (50-300 keV).
The time-averaged spectrum from T0-4.1 s to T0+194.6 s is
best fit by a Band function with Epeak = 968 +/- 16 keV,
alpha = -1.08 +/- 0.00, and beta = -2.38 +/- 0.03

The event fluence (10-1000 keV) in this time interval is
(550.3 +/- 1.39)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+135.7 s in the 10-1000 keV band
is 123.1 +/- 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: GRB160821A
Detection_method: Fermi LAT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19836
SUBJECT: GRB 160821A: Fermi-LAT refined analysis
DATE:    16/08/22 06:01:24 GMT
FROM:    Makoto Arimoto at Tokyo Inst of Tech  <arimoto@hp.phys.titech.ac.jp>

M. Arimoto (Waseda U./Tokyo Tech), M. Axelsson (KTH Stockholm), F.
Dirirsa (U. Johannesburg) and F. Longo (INFN/Trieste)
report on behalf of the Fermi-LAT team:
We report the on-ground localization and analysis of GRB 160821A,
which triggered
an onboard LAT detection (McEnery et al., GCN 19831).  All times are
relative to the initial GBM
trigger (Stanbro et al., GCN 19835).
The best LAT on-ground location is found to be:
RA, Dec = 171.3, 42.3 deg (J2000)
with an error radius of 0.08 deg (90 % containment, statistical error
only). This is fully
compatible with the position of the prompt emission detected by
Swift/BAT (Siegel et al., GCN 19830).
This was 17 deg from the LAT boresight at the time of the GBM trigger
and triggered
an autonomous repoint of the spacecraft.

More than 50 photons above 100 MeV and 4 photons above 1 GeV were
detected within 245s,
before the spacecraft entered the SAA. The GRB did not come back into
the Fermi-LAT FoV until T0 + 1380s.

 The LAT emission was coincident with the bright pulse observed by GBM
at ~T0+135 s.
The highest-energy photon is a 4.7 GeV event which is observed ~212
seconds after the GBM trigger.


The Fermi-LAT point of contact for this burst is Francesco Longo
(francesco.longo@trieste.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: GRB160821B
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19837
SUBJECT: GRB 160821B: Enhanced Swift-XRT position
DATE:    16/08/22 07:39:48 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 1754 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 160821B, 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 = 279.97653, +62.39129 which is equivalent
to:

RA (J2000): 18h 39m 54.37s
Dec (J2000): +62d 23' 28.6"

with an uncertainty of 2.5 arcsec (radius, 90% confidence).

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

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


GRB_name: GRB160821B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19838
SUBJECT: Short GRB 160821B: MASTER early  optical observations  
DATE:    16/08/22 09:08:42 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

R. Rebolo, M. Serra-Ricart, G. Israelian, N. Lodieu
The Instituto de Astrofisica de Canarias

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

K.Ivanov, O.Gres, N.M.Budnev, S.Yazev,
Irkutsk State University

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

A. Tlatov, V.Senik, D. Dormidontov, A.Parkhomenko
Kislovodsk Solar Station of the Pulkovo Observatory

V.Yurkov, Yu.Sergienko, A.Gabovich
Blagoveschensk Educational State University, Blagoveschensk

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

R.Podesta, C.Mallamaci, C.Lopez, F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA)

MASTER-IAC  twin robotic telescope (MASTER-Net: 
http://observ.pereplet.ru, online view http://161.72.133.2/) 
located in IAC (Tenerife, Spain) was pointed to the 
GRB160821B (Siegel et al., GCN 19833) 34 sec after notice time 
and 53 sec after trigger time at 2016-08-21 22:30:06 UT.
  The alert coordinates altitude was 55 deg. at MASTER-IAC, the Sun 
altitude was -35d, the Moon distance is 90 degrees.

On our first (10s exposure - two images in perpendicular polarizations)
set  we  not found optical transient within SWIFT error-box (Evans et al., GCN 19837)
and at NOT OT position  (Xu et al., GCN 19834) brighter then 16.6.


The resuts of the first 5 minutes observations are:

Id  Pro.type UT Exp.time   Limit Filt.   Tube.
                       (Start)     (s)     (5sigma)  (polarizator)

285342   Alert       22:30:06     10       16.6           P-      WEST
285343   Alert       22:30:06     10       16.6           P|      EAST
285342   Alert       22:30:06     10       16.6           P-      WEST
285345   Alert       22:30:43     20       17.1           P|      EAST
285346   Alert       22:31:24     30       17.1           P-      WEST
285347   Alert       22:31:24     30       16.6           P|      EAST
285348   Alert       22:32:08     30       16.6           P-      WEST
285349   Alert       22:32:08     30       16.6           P|      EAST
285350   Alert       22:32:50     40       17.2           P-      WEST
285351   Alert       22:32:50     40       17.0           P|      EAST
285352   Alert       22:33:43     50       17.3           P-      WEST
285353   Alert       22:33:43     50       17.2           P|      EAST
285355  Alert       22:34:46   70    17.5           P-   WEST
285354  Alert       22:34:46   70     0.0           P|   EAST

The limit of the coadded west tube images is 18.7 with start time 
22:30:06, finish time =  22:35:56 and mean time = 22:33:01 UT.


The message may be cited.


GRB_name: GRB160821B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19839
SUBJECT: GRB 160821B: Swift/UVOT Upper Limits
DATE:    16/08/22 12:46:33 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld@ucl.ac.uk>

A. A. Breeveld (UCL-MSSL) and M. H. Siegel (PSU) report on behalf of the 
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 160821B 76 
s after the BAT trigger (Siegel et al., GCN Circ. 19833).
No optical afterglow consistent with the XRT position (Evans et al. GCN 
Circ. 19837) or the NOT position (Xu et al. GCN Circ. 19834) 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            76          226          147         >21.1
u_FC               288          501          209         >20.4
white               76         6306          344         >21.7
v                 5080         5280          197         >19.1
b                 5901         6101          197         >20.2
u                  288         5895          406         >20.6
w1                5491         5691          197         >19.6
m2                5285         5485          197         >19.5
w2                4875         6439          322         >20.1

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).


GRB_name: GRB160821A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19840
SUBJECT: GRB 160821A: Swift-BAT refined analysis
DATE:    16/08/22 14:04:04 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),
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. H. Siegel (PSU), 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 the recent telemetry downlink,
we report further analysis of BAT GRB 160821A (trigger #709351)
(Siegel, et al. GCN Circ. 19830).  The BAT ground-calculated position is
RA, Dec = 171.254, 42.345 deg which is
  RA(J2000)  =  11h 25m 00.9s
  Dec(J2000) = +42d 20' 43.0"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 79%.

The mask-weighted light curve shows a complex structure with many
overlapping pulses that starts at ~T-3 s and extends beyond T+117s,
when the the burst went out of the BAT FOV due to a pre-planned slew.
The burst flux was rising during the slew, so it is possible that the BAT
detector missed the peak emission. The main peak that is visible in
the BAT light curve occurs at ~T+114 s.

The time-averaged spectrum from T-2.61 to T+115.17 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.52 +- 0.06.  The fluence in the 15-150 keV band is 7.2 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+113.51 sec in the 15-150 keV band
is 2.8 +- 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/709351/BA/


GRB_name: GRB160821B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19841
SUBJECT: GRB 160821B: Swift-XRT refined Analysis
DATE:    16/08/22 14:18:55 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), J.P. Osborne (U.
Leicester), K.L. Page (U. Leicester), B. Mingo (U. Leicester), A.
Maselli  (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB),
T.G.R. Roegiers (PSU) and M.H. Siegel report on behalf of the Swift-XRT
team:

We have analysed 9.5 ks of XRT data for GRB 160821B (Siegel et al. GCN
Circ. 19833), from 56 s to 35.9 ks after the  BAT trigger. The data
comprise 198 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. 19837).

The late-time light curve (from T0+4.9 ks) can be modelled with a
power-law decay with a decay index of alpha=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 1.95 (+0.08, -0.07). The
best-fitting absorption column is  7.5 (+2.0, -1.7) x 10^20 cm^-2,
consistent with the Galactic value of 5.8 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 3.3 x 10^-11 (3.9 x
10^-11) erg cm^-2 count^-1. 

A summary of the WT-mode spectrum is thus:
Total column:      7.5 (+2.0, -1.7) x 10^20 cm^-2
Galactic foreground: 5.8 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.95 (+0.08, -0.07)

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 3.8 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x
10^-13 (1.4 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/00709357.

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


GRB_name: GRB160821A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19842
SUBJECT: Konus-Wind observation of GRB 160821A
DATE:    16/08/22 16:40:49 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks, P. Oleynik,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration, very bright GRB 160821A
(Swift detection: Siegel et al., GCN 19830; Fermi LAT detection:
McEnery et al., GCN 19831, Arimoto et al., GCN 19836;
Fermi GBM observation: Stanbro et al., GCN 19835)
triggered Konus-Wind at T0=74179.687 s UT (20:36:19.687).

The burst light curve shows a weak emission starting at ~T0-113 s
followed by the bright main episode at ~T0. A total duration of
the burst is ~320 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/GRB160821_T74179/

As observed by Konus-Wind, the burst
had a fluence of 1.17(-0.03,+0.03)x10^-3 erg/cm2,
and a 64-ms peak flux, measured from T0+22.320 s,
of 1.06(-0.13,+0.13)x10^-4 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+99.328 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 = -1.00(-0.02,+0.02),
the high energy photon index beta = -1.99(-0.04,+0.04),
the peak energy Ep = 710(-44,+47) keV
(chi2 = 212/88 dof)

The spectrum near the maximum count rate
(measured from T0+22.272 to T0+22.528 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 = -0.84(-0.10,+0.12),
the high energy photon index beta = -1.89(-0.29,+0.17),
the peak energy Ep = 1074(-326,+431) keV
(chi2 = 54/57 dof)

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


GRB_name: GRB160821B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19843
SUBJECT: GRB 160821B: Fermi GBM Detection
DATE:    16/08/22 20:18:16 GMT
FROM:    Matthew Stanbro at UAH/Fermi  <mcs0001@uah.edu>

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

"At 22:29:13.33 UT on 21 August 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160821B (trigger 493511357 / 160821937), which
was also detected by the Swift/BAT (Siegel et al. 2016, GCN 19833)
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 61
degrees.

The GBM light curve consists of a few episodes
with a duration (T90) of about 1 s (50-300 keV).
The time-averaged spectrum from T0-0.13 s to T0+0.32 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.37 +/- 0.22 and
the cutoff energy, parameterized as Epeak, is 84 +/- 19 keV

The event fluence (10-1000 keV) in this time interval is
(1.68 +/- 0.19)E-06 erg/cm^2. The 64-millisec peak photon flux measured
starting from T0+0.00 s in the 10-1000 keV band
is 9.16 +/- 1.19 ph/s/cm^2.

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


GRB_name: GRB160821B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19844
SUBJECT: GRB 160821B: Swift-BAT refined analysis
DATE:    16/08/22 21:17:29 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@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. P. Norris (BSU),
T. Sakamoto (AGU), M. H. Siegel (PSU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL), G. Younes (GWU) (i.e. the Swift-BAT team):

Using the data set from T-239 to T+690 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 160821B (trigger #709357)
(Siegel, et al., GCN Circ. 19833).  The BAT ground-calculated position is
RA, Dec = 280.005, 62.387 deg which is
  RA(J2000)  =  18h 40m 01.2s
  Dec(J2000) = +62d 23' 13.2"
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 85%.

The mask-weighted light curve shows a FRED-like structure that starts
and peaks at ~T0, and ends at ~T+0.5 s. T90 (15-350 keV) is
0.48 +- 0.07 sec (estimated error including systematics).

The time-averaged spectrum from T+0.00 to T+0.54 sec is best fit by a
power law with an exponential cutoff. This fit gives a photon index of
0.11 +/- 0.88 and an Epeak of 46.3 +/- 6.4 keV (chi squared 58.76 for 56 d.o.f.).
For this model the total fluence in the 15-150 keV band is
1.0 +/- 0.1 x 10^-7 erg/cm2, and the 1-sec peak flux measured from
T-0.23 sec in the 15-150 keV band is 1.7 +/- 0.2 ph/cm2/sec.
A fit to a simple power law gives a photon index of 1.88 +- 0.15
(chi squared 75.26 for 57 d.o.f.).  All the quoted errors are at the
90% confidence level.

The burst spectrum is on the softer end of the BAT short GRB distribution.
Using a 4-ms binned light curve, the lag analysis finds a lag of
8 +/- 4 ms for the 50-100 keV to 15-25 keV band, which is consistent with
those of a short GRB.

In addition to a short GRB, the BAT light curve and spectrum are also consistent
with those expected from an SGR. In particular, the double blackbody model
also produces an acceptable fit to the time-averaged spectrum
(chi squared 56.65 for 55 d.o.f.), with the blackbody temperatures
(kT1=4.05 and kT2=13.22 keV) consistent with those from an SGR. However,
the location of this burst (Galactic latitude of 25.13 deg and not in SMC or LMC),
and the fast decay of the XRT light curve makes it unlikely to be an SGR.

We therefore conclude that this burst is likely to be a short GRB.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/709357/BA/


GRB_name: GRB160822A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19845
SUBJECT: GRB 160822672: Fermi GBM detection
DATE:    16/08/23 01:10:37 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007@uah.edu>

R. Hamburg (UAH), C. Meegan (UAH), and A. Goldstein (USRA)
report on behalf of the Fermi GBM Team:

"At 16:07:40.01 UT on 22 August 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160822A (trigger 493574864 / 160822672).

The on-ground calculated location, using the GBM trigger
data, is RA = 270, DEC = +8, with an uncertainty
of 5 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which we have characterized as a core-plus-tail model, with 90% of
GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg
systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).

The angle from the Fermi LAT boresight at the GBM trigger time is 58
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 ARR was accepted and the spacecraft slewed to the on-board
localization, 160 degrees from the LAT boresight.  The more reliable
on-ground
localization placed the GRB at a location ~100 deg away from the onboard
localization.  The ARR was then canceled and replaced with a short TOO
at the on-ground localization.

The GBM light curve shows a single peak
with a duration (T90) of about 0.4 s (50-300 keV).
The time-averaged spectrum from T0-0.13 s to T0+0.13 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.05 +/- 0.10 and
the cutoff energy, parameterized as Epeak, is 1166.00 +/- 560.00 keV.

The event fluence (10-1000 keV) in this time interval is
(7.33 +/- 0.49)E-07 erg/cm^2. The 0.064-sec peak photon flux measured
starting from T0+0.0 s in the 10-1000 keV band
is 22 +/- 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: GRB160821B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19846
SUBJECT: GRB 160821B: WHT afterglow confirmation and redshift of candidate host
DATE:    16/08/23 04:31:26 GMT
FROM:    Andrew Levan at U.of Leicester  <A.J.Levan@warwick.ac.uk>

A.J. Levan (U. Warwick), K. Wiersema (U. Leicester), N.R. Tanvir (U. Leicester), D. Malesani (DARK/NBI, DTU Space), D. Xu (NAOC/CAS), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI) report for a larger collaboration: 

We observed the location of GRB 160821B (Siegel et al. GCN 19833) with the William Herschel Telescope on La Palma, beginning at 22:57UT on 22 Aug 2016. Observations were obtained in the r and z bands. The candidate afterglow (Xu et al. GCN 19834) is present in our images, but has faded by approximately a factor of two between the two epochs taken approximately one day apart. This variability confirms the source as the afterglow of GRB 160821B. 

In addition we obtained a spectrum of the candidate host galaxy (Xu et al. GCN 19834). Several prominent emission lines are visible, including Hbeta, [OIII] (4959/5007) and H-alpha, at a provisional redshift of z=0.16. 

The offset of the afterglow from the candidate host galaxy is approximately 5.5â€, corresponding to a physical offset of 15 kpc. While we cannot rule out a chance alignment of the afterglow with the host galaxy, we also note that the galaxy light does apparently extend to approximately the afterglow position. 

We thank the staff of WHT, in particular Cecelia Farina, for their help with these observations.


GRB_name: GRB160821B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19847
SUBJECT: GRB 160821B: GTC follow-up observation
DATE:    16/08/23 04:45:23 GMT
FROM:    Soomin Jeong at IAA-CSIC  <sjeong@iaa.es>

S. Jeong (SKKU/IAA-CSIC), I. H. Park (SKKU), Y. Hu (IAA-CSIC), R. Scarpa
(GTC) and A. J. Castro-Tirado (IAA-CSIC), on behalf of a larger
collaboration report:

We observed the field of the short GRB 160821B detected by Swift (Siegel et
al. GCNC
19833) and Fermi (Stanbro et al. GCNC 19843) using the 10.4m Gran
Telescopio Canarias (GTC)
equipped with OSIRIS. Observations started at 00:16:17.480 UT on Aug 22
(i.e.,
1.78 hr after the burst), in the riz-band filters.

We also detect the point-like source proposed by Xu et al. (GCNC 19834) as
a potential
afterglow candidate) within the XRT error circle reported by Siegel et al.
(GCNC 19833),
for which we measure a preliminary magnitude (pending final calibration) of
R = 22.40+/-0.06
at 1.83 hr after the burst.

Lacking variability, unless there is an initial plateau phase lasting
several hour in the
afterglow brightness, this would be consistent with a host galaxy detection.
Further GTC observations are planned.

We thanks D. Xu and D. Malesani for providing secondary reference stars in
the field.


GRB_name: GRB160623A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19848
SUBJECT: Possible radio detection of GRB160623A with the GMRT
DATE:    16/08/23 09:54:20 GMT
FROM:    Nayana A J at NCRA-TIFR  <nayan89deva@gmail.com>

A.J Nayana  (NCRA-TIFR), Poonam Chandra (NCRA-TIFR), A. R. Rao (TIFR), Dipankar
Bhattacharya (IUCAA) and Varun Bhalerao (IUCAA) report:

We carried out Giant Metrewave Radio Telescope (GMRT) observations of GRB 160623A
(Vianello et al. GCN Circ. 19553) at 1460 MHz band on 2016 Aug 04.91 UT. We detect a
4.5-sigma source at the GRB position (Vianello et al. GCN Circ. 19553) with a flux
density of 207+/-78 uJy. This is most likely the radio afterglow of GRB 160623A. Map rms
is 50 uJy.

We thank GMRT staff for making these observations possible.


GRB_name: GRB160703A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19849
SUBJECT: Possible radio detection of GRB160703A with the GMRT
DATE:    16/08/23 09:58:51 GMT
FROM:    Nayana A J at NCRA-TIFR  <nayan89deva@gmail.com>

A.J Nayana  (NCRA-TIFR), Poonam Chandra (NCRA-TIFR), A. R. Rao (TIFR), Dipankar
Bhattacharya (IUCAA) and Varun Bhalerao (IUCAA) report:

We carried out Giant Metrewave Radio Telescope (GMRT) observations of GRB 160703A (Cenko
et al. GCN Circ. 19645) at 1460 MHz band on 2016 Aug 11.79 UT. We detect a faint source
at the GRB position (Cenko et al. GCN Circ. 19645) with a flux density of 166+/-46 uJy.
This is most likely the radio afterglow of GRB 160703A. Map rms is 40 uJy.

We thank GMRT staff for making these observations possible.


GRB_name: GRB160820A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19850
SUBJECT: IPN Triangulation of GRB 160820A (short/hard)
DATE:    16/08/23 10:40:26 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova,
and T. Cline on behalf of the Konus-Wind team,

K. Hurley, on behalf of the IPN,

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,

and

S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer,
on behalf of the Swift-BAT team, report:

A short-duration, hard-spectrum GRB 160820A was detected by Fermi
(GBM; trigger 493386854), Konus-Wind, INTEGRAL (SPI-ACS),
and Swift (BAT) at about 42851 s UT (11:54:11).
The burst was outside the coded field of view of the BAT.

We have triangulated it to a preliminary, 3 sigma error box whose
coordinates are:
   ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
    11.338 (00h 45m 21s) +24.933 (+24d 55' 59")
  Corners:
     8.000 (00h 32m 00s) +28.159 (+28d 09' 33")
    15.644 (01h 02m 35s) +22.544 (+22d 32' 38")
    14.155 (00h 56m 37s) +21.358 (+21d 21' 28")
     6.447 (00h 25m 47s) +26.868 (+26d 52' 04")
  ---------------------------------------------
The error box area is 16.23 sq. deg, and its maximum
dimension is 9.4 deg (the minimum one is 1.82 deg).
The Sun distance was 123 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB160820_T42855/IPN/

The time history and spectrum will be given in forthcoming GCN Circulars.


GRB_name: GRB160820A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19851
SUBJECT: Konus-Wind observation of GRB 160820A
DATE:    16/08/23 11:00:14 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, S. Golenetskii, R.Aptekar, D. Frederiks, P. Oleynik,
M. Ulanov, A. Tsvetkova, A. Lysenko, A. Kozlova, and T. Cline
on behalf of the Konus-Wind team, report:

The short-duration, hard-spectrum GRB 160820A
(IPN triangulation: Svinkin et al., GCN 19850)
triggered Konus-Wind at T0=42855.115 s UT (11:54:15.115).

The burst light curve shows a single pulse with a total duration
of ~0.2 s.

As observed by Konus-Wind, the burst
had a fluence of 7.54(-0.86,+0.94)x10^-7 erg/cm2
and a 16-ms peak flux, measured from T0-0.058 s,
of 5.63(-1.50,+1.52)x10^-6 erg/cm2/s
(both in the 20 - 1000 keV energy range).

Since a major fraction of the burst counts was accumulated
before the trigger, the spectral analysis was performed using
the KW 3-channel light curve data.
Modeling the 3-channel time-integrated spectrum
(measured from T0-0.158 s to T0+0.074 s)
by the cutoff power law yields the following model parameters:
the photon index alpha=0.87(-0.78,+2.13),
and the peak energy Ep=383(-67,+73) keV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB160820_T42855/

All the quoted errors are at the 68% confidence level.
All the quoted values are preliminary.


GRB_name: GRB160822A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19852
SUBJECT: IPN Triangulation of GRB 160822A (short/hard)
DATE:    16/08/24 00:18:54 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova,
and T. Cline on behalf of the Konus-Wind team,

K. Hurley, on behalf of the IPN,

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,

and

S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer,
on behalf of the Swift-BAT team, report:

The short-duration, hard-spectrum, bright GRB 160822A has been detected 
by Fermi (GBM; Hamburg et al., GCN Circ. 19845), Konus-Wind, INTEGRAL 
(SPI-ACS), and Swift (BAT) at about 58060 s UT (16:07:40). The burst was 
outside the coded field of view of the BAT.

We have triangulated it to a preliminary, 3 sigma error box whose
coordinates are:
---------------------------------------------
    RA(2000), deg                 Dec(2000), deg
   ---------------------------------------------
   Center:
    272.129 (18h 08m 31s)  +3.584 ( +3d 35' 01")
   Corners:
    272.065 (18h 08m 16s)  +1.771 ( +1d 46' 15")
    271.809 (18h 07m 14s)  +1.779 ( +1d 46' 45")
    272.205 (18h 08m 49s)  +5.396 ( +5d 23' 45")
    272.462 (18h 09m 51s)  +5.389 ( +5d 23' 19")
   ---------------------------------------------
The error box area is 3348 sq. arcmin, and its maximum
dimension is 3.67 deg (the minimum one is 15.4 arcmin).
The Sun distance was 118 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB160822_T58061/IPN/

The Konus-Wind time history and spectrum will be given in forthcoming 
GCN Circulars.


GRB_name: GRB160822A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19853
SUBJECT: Konus-Wind observation of GRB 160822A
DATE:    16/08/24 11:37:30 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks, 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 160822A
(Fermi GBM detection: Hamburg et al., GCN Circ. 19845;
IPN triangulation: Svinkin et al., GCN Circ. 19852)
triggered Konus-Wind at T0=58061.153 s UT (16:07:41.153).

The burst light curve shows a single pulse
which starts at T0-0.016 s with a total duration of 0.03 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/GRB160822_T58061/

As observed by Konus-Wind, the burst
had a fluence of 7.60(-1.87,+5.46)x10^-7 erg/cm2,
and a 16-ms peak flux, measured from T0-0.006 s,
of 3.95(-1.40,+4.02)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The spectrum of the burst
(measured from T0 to T0+0.064 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -0.59 (-0.75,+1.34)
and Ep = 599 (-222,+2249) keV (chi2 = 11/14 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -1.9
(chi2 = 11/13 dof)

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


GRB_name: GRB160821B
Detection_method: VLA Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19854
SUBJECT: GRB 160821B: VLA 5.0 GHz observations
DATE:    16/08/24 20:22:19 GMT
FROM:    Wen-fai Fong at U of Arizona  <wfong@email.arizona.edu>

W. Fong (University of Arizona), K. D. Alexander (Harvard), and T. Laskar
(NRAO/UC Berkeley) report:

"We observed the position of the short-duration GRB 160821B (Siegel et al.,
GCN 19833) with the Karl G. Jansky Very Large Array (VLA) beginning on 2016
Aug 22.088 UT (3.6 hr post-burst) at a mean frequency of 5.0 GHz. In 1 hour
of observations, we detect a faint radio source at the position:

RA(J2000) = 18:39:54.56
Dec(J2000) = 62:23:30.3

with an uncertainty of 0.3" in each coordinate. This position is consistent
with the position of the X-ray afterglow (Evans et al., GCN 19837), and
coincident with the position of the optical afterglow (Xu et al., GCN
19834; Levan et al., GCN 19846).

We measure a preliminary 5.0 GHz flux density of ~35 microJy. To assess
variability, we obtained an additional set of VLA observations starting at
26.5 hr after the burst. The source is no longer detected in these
observations to a 3-sigma limit of 18 microJy.

Due to the fading of the radio source, as well as the positional
coincidence with the X-ray and optical afterglows, we suggest this source
as the radio afterglow of GRB 160821B.

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


GRB_name: GRB160824A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19855
SUBJECT: GRB 160824A: Swift detection of a burst
DATE:    16/08/24 23:40:59 GMT
FROM:    Kim Page at U.of Leicester  <klp5@leicester.ac.uk>

P.A. Evans (U Leicester), S. B. Cenko (GSFC),
H. A. Krimm (CRESST/GSFC/USRA), A. Y. Lien (GSFC/UMBC),
F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester) and
M. H. Siegel (PSU) report on behalf of the Swift Team:

At 23:22:25 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160824A (trigger=709765).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 80.078, +40.040 which is 
   RA(J2000) = 05h 20m 19s
   Dec(J2000) = +40d 02' 25"
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 ~2100 counts/sec (15-350 keV), at ~5 sec after the trigger. 

The XRT began observing the field at 23:23:56.5 UT, 91.1 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source with an enhanced position: RA, Dec
80.0877, 40.0286 which is equivalent to:
   RA(J2000)  = 05h 20m 21.05s
   Dec(J2000) = +40d 01' 43.1"
with an uncertainty of 2.1 arcseconds (radius, 90% containment). This
location is 48 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 (6.32 x
10^21 cm^-2, Willingale et al. 2013), with an excess column of 4.7
(+6.16/-4.59) x 10^21 cm^-2 (90% confidence). 

The initial flux in the 2.5 s image was 1.04e-08 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 101 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 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: GRB160824B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19856
SUBJECT: GRB 160824B: Fermi GBM detection
DATE:    16/08/25 02:27:41 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007@uah.edu>

R. Hamburg (UAH)
reports on behalf of the Fermi GBM Team:

"At 14:21:12.94 UT on 24 August 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160824B (trigger 493741276 / 160824598).

The on-ground calculated location, using the GBM trigger
data, is RA = 73, DEC = +68, with an uncertainty
of 1 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which we have characterized as a core-plus-tail model, with 90% of
GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg
systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).

The angle from the Fermi LAT boresight at the GBM trigger time is 121
degrees.

The GBM light curve consists of a single peak
with a duration (T90) of about 3.6 s (50-300 keV).
The time-averaged spectrum from T0-0.26 to T0+3.07 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.20 +/- 0.06 and
the cutoff energy, parameterized as Epeak, is 649.70 +/- 32.60 keV.

The event fluence (10-1000 keV) in this time interval is
(1.39 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.7 s in the 10-1000 keV band
is 11.9 +/- 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: GRB160824A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19857
SUBJECT: GRB 160824A: Enhanced Swift-XRT position
DATE:    16/08/25 07:28:12 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 2198 s of XRT Photon Counting mode data and 5 UVOT
images for GRB 160824A, 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 = 80.08758, +40.02826 which is equivalent
to:

RA (J2000): 05h 20m 21.02s
Dec (J2000): +40d 01' 41.7"

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: GRB160824A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19858
SUBJECT: GRB 160824A: Swift-XRT refined Analysis
DATE:    16/08/25 12:29:35 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

We have analysed 10 ks of XRT data for GRB 160824A (Evans et al. GCN
Circ. 19855), from 81 s to 29.6 ks after the  BAT trigger. The data
comprise 105 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 Goad et al.
(GCN Circ. 19857).

The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=3.33 (+0.17, -0.18). At T+258 s  the decay
flattens to an alpha of 0.44 (+0.05, -0.06) before breaking again at
T+7762 s to a final decay with index alpha=1.31 (+/-0.14).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.07 (+/-0.10). The
best-fitting absorption column is  1.18 (+0.11, -0.10) x 10^22 cm^-2,
in excess of the Galactic value of 6.3 x 10^21 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.96 (+/-0.13) and a
best-fitting absorption column of 1.05 (+0.14, -0.13) x 10^22 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 5.0 x 10^-11 (9.1 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.05 (+0.14, -0.13) x 10^22 cm^-2
Galactic foreground: 6.3 x 10^21 cm^-2
Excess significance: 5.3 sigma
Photon index:      1.96 (+/-0.13)

If the light curve continues to decay with a power-law decay index of
1.31, the count rate at T+24 hours will be 0.018 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.8 x
10^-13 (1.6 x 10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00709765.

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


GRB_name: GRB160824A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19859
SUBJECT: GRB 160824A: Bassano Bresciano Observatory upper limits
DATE:    16/08/25 12:42:52 GMT
FROM:    Ulisse Quadri at Bassano Bresciano Obs  <oabb@ulisse.bs.it>

U.Quadri, L.Strabla and R.Girelli report:

We imaged the field of GRB 160824A detected by SWIFT(trigger 709765)
with the robotic telescope of (IAU station 565) Bassano Bresciano 
Observatory, Italy. Member of: 
AAVSO - American Association of Variable Star Observers.
ISSP - Italian Supernovae Search Project.
UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili.

The observations started 20.77 min after the GRB trigger,  
with our Schmidt telescope D=320/400 mm F/D=3.1.

Weather conditions not good for Moon proximity.

We co-added 4 series of 20 exposures of 120 sec each.

Start T0+      End T0+      CVlim
20.77 min    196.52 min     17.5

We did not found any optical counterpart in the error box of the XRTcandidate.
P.A. Evans (U Leicester), S. B. Cenko (GSFC), et al.

Magnitudes were estimated with the UCAC4 cat. and 
are not corrected for galactic dust extinction.

Reference:
http://www.osservatoriobassano.org/GRB.asp

The message may be cited.


GRB_name: GRB160824A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19860
SUBJECT: GRB 160824A: Swift/UVOT Possible Afterglow Detection
DATE:    16/08/25 14:25:28 GMT
FROM:    Frank Marshall at GSFC  <femarsha@khamseen.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC) 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 160824A
101 s after the BAT trigger (Evans et al., GCN Circ. 19855).
UVOT marginally detects a source consistent with the enhanced XRT position
(Goad et al. GCN Circ. 19857)
in the initial UVOT exposure with the white filter.

The preliminary analysis produces the following marginal detection 
and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373):

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

white              101          787          186         20.16 +/- 0.27
v                  645          837           39        >17.9
b                  571          763           39        >18.7
u                  313          738          265        >19.7
w1                 694          714           19        >18.5
m2                 669          861           39        >19.2
w2                 620          813           39        >18.5

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.69 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB160824A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19861
SUBJECT: GRB 160824A: Swift-BAT refined analysis
DATE:    16/08/25 16:50:54 GMT
FROM:    Hans Krimm at NASA-GSFC  <hans.a.krimm@nasa.gov>

T. Sakamoto (AGU), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
P.A. Evans (U Leicester), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
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 160824A (trigger #709765)
(Evans, et al., GCN Circ. 19855).  The BAT ground-calculated position is
RA, Dec = 80.087, 40.039 deg which is
    RA(J2000)  =  05h 20m 20.8s
    Dec(J2000) = +40d 02' 21.6"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 55%.

The mask-weighted light curve shows two episodes of emission.  The first runs
from T-5 sec to roughly T+45 sec and contains multiple peaks.  The second runs
from T+85 sec to T+110 sec.  T90 (15-350 keV) is 99.3 +- 7.8 sec (estimated 
error including systematics).

The time-averaged spectrum from T-0.66 to T+111.58 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.64 +- 0.11.  The fluence in the 15-150 keV band is 2.6 +- 0.2 x 10^-6 erg/cm2. 
The 1-sec peak photon flux measured from T+4.88 sec in the 15-150 keV band is 
1.3 +- 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/709765/BA/

[GCN OPS NOTE(25aug16):  Per author's request, the TBDs for the time range
of the spectral average was filled in with the actual values.]


GRB_name: GRB160824A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19862
SUBJECT: GRB 160824A: ISON/Terskol optical observations
DATE:    16/08/25 18:20:16 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI), A. Mokhnatkin (KIAM),  A. Volnova (IKI), Molotov (KIAM), 
A. Pozanenko  (IKI) report on behalf of larger GRB follow-up collaboration

We observed the field of GRB 160824A (Evans   et al., GCN 19855)  with K-800 
(0.8m f/2.9)   telescope  of ISON/Terskol   observatory. We obtained several 
unfiltered images starting on  August 24 (UT) 23:58:36.  We detected 
optical source in coordinates
(J2000) 05:20:21.18 +40:01:43.5 with uncertainty of 1 arcsec in both 
coordinates. This is 2.6 arcsec apart of the center of the enhanced XRT 
error circle (Goad et al., GCN 19857).  At this time we cannot say nothing 
about variability of the object.  It is not clear whether our source is the 
same as the source reported by Marshall et al. (GCN 19860).  Preliminary 
photometry of a combined image is following

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

2016-08-24 23:58:36 0.02758 CR      400    20.6   0.3  20.9

Photometry is based on nearby USNO-B1.0 stars
USNO-B1.0_id    R2
1300-0122742    18.17
1300-0122665    18.04
1300-0122653    18.66
1300-0122680    17.00
1300-0122864    17.60
1299-0128308    18.00
1300-0122784    17.56


GRB_name: GRB160824A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19863
SUBJECT: GRB 160824A: 1.5m OSN I-band observation
DATE:    16/08/25 19:08:04 GMT
FROM:    Youdong HU at IAA-CSIC, UGR  <youdong@iaa.es>

Y. Hu, A. Sota and A.J. Castro-Tirado (IAA-CSIC Granada), on behalf of a 
larger collaboration, report:

Following the detection of GRB 160824A by Swift (Evans et al. GCNC 
19855), optical images in the I-band  were obtained at the 1.5m OSN 
telescope in Granada (Spain) starting at 01:25 (Aug 25), i.e. 2.05 h 
postburst. No optical afterglow is detected in the co-added image (13 x 
300s, mid time 02:00 UT, 2.6 h after the trigger) within the enhanced 
Swift/XRT error box (Goad et al. GCNC 19857) down to I = 20.0.


GRB_name: GRB160825A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19864
SUBJECT: GRB 160825A: Swift ToO observations
DATE:    16/08/26 00:38:18 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 ToO observation of the INTEGRAL GRB 160825A. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020686

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 INTEGRAL 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: GRB160821A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19865
SUBJECT: GRB 160821A: CALET Gamma-Ray Burst Monitor detection
DATE:    16/08/26 01:59:26 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

P. S. Marrocchesi (U of Siena), A. Yoshida, T. Sakamoto, Y. Kawakubo,
M. Moriyama, Y. Yamada (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA),
I. Takahashi (IPMU), Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U), W. Ishizaki (ICRR),
M. L. Cherry (LSU), S. Ricciarini (U of Florence),
and the CALET collaboration:

The long-duration GRB 160821A (Siegel et al., GCN Circ. 19830;
McEnery et al., GCN Circ. 19831; Stanbro et al., GCN Circ. 19835;
INTEGRAL-SPI/ACS trigger #7537) triggered the CALET Gamma-ray Burst Monitor
(CGBM) at 20:36:21.91 on 21 August 2016.  The burst signal was seen by
all CGBM instruments.  Note that the CGBM trigger time is 111 sec after
the trigger time of Swift/BAT.  This is because the CGBM triggered at the
bright main peak of the burst (Markwardt et al. GCN Circ. 19840).

The light curve of the SGM shows a bright peak with several overlapping
pulses.  The emission starts from T sec, peaks at T+24 sec and ends at
T+80 sec.  There is a hint of the emission in the SGM light curve around
the trigger time of Swift/BAT.  The T90 duration measured by the SGM data
is 35.1 +- 0.8 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1155846835/

The CALET data used in this analysis are provided by the Waseda
CALET Operation Center located at the Waseda University.


GRB_name: GRB160826A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19866
SUBJECT: GRB 160826A: Swift detection of a burst
DATE:    16/08/26 06:29:47 GMT
FROM:    Kim Page at U.of Leicester  <klp5@leicester.ac.uk>

B. Mingo (U Leicester), H. A. Krimm (CRESST/GSFC/USRA),
K. L. Page (U Leicester) and M. H. Siegel (PSU) report on behalf of
the Swift Team:

At 06:12:38 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160826A (trigger=709907).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 183.074, -67.689 which is 
   RA(J2000) = 12h 12m 18s
   Dec(J2000) = -67d 41' 19"
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 30 sec.  The peak count rate
was ~1300 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 06:14:20.8 UT, 102.5 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source located at RA, Dec 183.11400,
-67.66411 which is equivalent to:
   RA(J2000)  = 12h 12m 27.36s
   Dec(J2000) = -67d 39' 50.8"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 104 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 4.59
x 10^21 cm^-2 (Willingale et al. 2013). 

The initial flux in the 2.5 s image was 5.77e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 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. 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 expected extinction corresponding
to E(B-V) of 0.47. 

Burst Advocate for this burst is B. Mingo (bm188 AT 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: GRB160821A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19867
SUBJECT: GRB160821A: Astrosat CZTI (veto) detection
DATE:    16/08/26 11:58:52 GMT
FROM:    Varun Bhalerao at IUCAA  <varunb@iucaa.in>

V. Bhalerao (IUCAA), V. Kumar (IUCAA), D. Bhattacharya (IUCAA), A. R. Rao (TIFR), S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:

The bright long GRB160821A (Barthelmy et al., GCN Circ. 19830) was detected using the CsI veto detectors on Astrosat CZTI (Bhalerao et al., arXiv:1608.03408). The primary CZTI detectors were disabled as the satellite was passing through the South Atlantic Anomaly at that time.

The source was clearly detected in the 40-200 keV energy range. The light curve shows a single peak, with the strongest peak at 20:36:45.00 UT, 133 seconds after BAT Trigger at 20:34:28 UT. The time delay arises from detection of the main peak of the burst, and the timing is consistent with the Fermi LAT (McEnery et al., GCN 19831) and CALET (Marrocchesi et al., GCN 19865). The peak count rate in the CsI detectors was 11200 counts/sec above the background (four quadrants summed together), with a total of 149300 counts. The local mean background count rate was 1400 counts/sec. Using cumulative rates, we measure a T90 of 42 secs.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb . CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB160826A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19868
SUBJECT: GRB 160826A: Swift-XRT refined Analysis
DATE:    16/08/26 15:36:20 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P.A. Evans (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), S.L. Gibson (U. Leicester), J.P.
Osborne (U. Leicester) and B. Mingo report on behalf of the Swift-XRT
team:

We have analysed 6.5 ks of XRT data for GRB 160826A (Mingo et al. GCN
Circ. 19866), from 93 s to 22.1 ks after the  BAT trigger. The data
comprise 114 s in Windowed Timing (WT) mode (the first 5 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The refined XRT position is RA, Dec = 183.1127, -67.6639 which is
equivalent to:

RA (J2000): 12 12 27.05
Dec(J2000): -67 39 50.0

with an uncertainty of 3.5 arcsec (radius, 90% confidence).

The light curve can be modelled with a power-law decay with a decay
index of alpha=1.64 (+0.06, -0.05).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.68 (+0.31, -0.28). The
best-fitting absorption column is  9.1 (+3.3, -2.7) x 10^21 cm^-2, in
excess of the Galactic value of 4.6 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 5.7 x 10^-11 (8.5 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      9.1 (+3.3, -2.7) x 10^21 cm^-2
Galactic foreground: 4.6 x 10^21 cm^-2
Excess significance: 2.7 sigma
Photon index:      1.68 (+0.31, -0.28)

If the light curve continues to decay with a power-law decay index of
1.64, the count rate at T+24 hours will be 2.1 x 10^-4 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x
10^-14 (1.7 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/00709907.

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


GRB_name: GRB160820A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19869
SUBJECT: GRB 160820A: Fermi GBM observation
DATE:    16/08/26 16:27:47 GMT
FROM:    Hoi-Fung Yu at MPE  <sptfung@mpe.mpg.de>

H.-F. Yu (MPE) and C.A. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 11:54:10.65 UT on 20 August 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160820A (trigger 493386854 / 160820496),
which was also detected by the Konus-Wind (Svinkin et al., GCN 19851)
and located by the Interplanetary Network (Svinkin et al., GCN 19850).
The GBM on-ground location is consistent with the IPN position.

The angle from the Fermi LAT boresight at the GBM trigger time is 63 degrees.

The GBM light curve shows a single pulse
with a duration (T90) of about 0.4 s (50-300 keV).
The time-averaged spectrum from T0-0.064 s to T0+0.192 s is
best fit by a Band function with Epeak = 810 +/- 200 keV,
alpha = -0.7 +/- 0.1, and beta = -2.6 +/- 0.8.

The event fluence (10-1000 keV) in this time interval is
(7.7 +/- 0.4)E-07 erg/cm^2. The 64-ms peak photon flux measured
starting from T0+0.000 s in the 10-1000 keV band
is 13 +/- 1 ph/s/cm^2.

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


GRB_name: GRB160825A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19870
SUBJECT: GRB 160825A: not localized by Swift
DATE:    16/08/26 18:52:44 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

D. M. Palmer (LANL) reports on behalf of the Swift team:

On 2016-08-25 at 09:39:29, INTEGRAL SPI ACS reported a 
trigger (#7539) via GCN.  Examination of the Swift/BAT count rates
at that time showed a simultaneous detection of a short hard
burst (duration ~0.1 s, with the detected flux predominantly 
above 50 keV).

On-board analysis of the data showed that the highest-significance
peak in the corresponding image was at a location 
ra,dec = 251.982, -7.833 (J2000) with a ~5 arcmin error radius.  
This peak is of marginal significance (5.6 sigma) and did not trigger
an automated follow-up observation.  

A preliminary analysis of the Time-of-Arrival difference between 
INTEGRAL and BAT lightcurves did not exclude this location.
Therefore, this was considered a possible GRB localization
and a ToO observation was requested.

Swift-XRT performed follow-up observations of this location, collecting
2.0 ks of Photon Counting (PC) mode data between T0+55.9 ks and 
T0+62.2 ks.

No X-ray sources have been detected within the 296 arcsec radius BAT 
error circle. The 3-sigma upper limit in the field is 0.004 ct s^-1, 
corresponding to a 0.3-10 keV observed flux of 1.5e-13 erg cm^-2 s^-1 
(assuming a typical GRB spectrum).

An uncatalogued source was detected, however this was too far from the GRB
position to be the afterglow.

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/00020686.

A more detailed analysis of the light curve TOA difference also
conclusively excludes the  BAT location as the true burst position.
(Dmitry Svinkin, private communication).

Based on these observations and analyses, we can exclude the
marginal image peak location as being the GRB location.

The simultaneous INTEGRAL and BAT detections proves that
there was a short GRB at that time, but it was most likely outside
of the BAT's imaging field of view.

[GCN OPS NOTE(26aug16): Per author's request, the mispelling and missing
word 'source' were fixed.]


GRB_name: GRB160826A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19871
SUBJECT: GRB 160826A: Swift/UVOT Upper Limits
DATE:    16/08/26 19:00:50 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@swift.psu.edu>

S. J. LaPorte (PSU) and B. Mingo (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 160826A
109 s after the BAT trigger (Mingo et al., GCN Circ. 19866).
No optical afterglow consistent with the XRT position
(Mingo et al. GCN Circ. 19868)
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           109          259          147         >21.1
u_FC               267          517          246         >19.8
white              109         1195          353         >22.1
v                  597         1245           78         >19.8
b                  523         1170           58         >20.2
u                  267         4893          340         >19.8
w1                 648         1290           74         >19.0
m2                 622         1269           78         >19.3
w2                 573         1220           78         >19.9

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.47 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB160826A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19872
SUBJECT: GRB 160826A: Swift-BAT refined analysis
DATE:    16/08/26 19:35:43 GMT
FROM:    Hans Krimm at NASA-GSFC  <hans.a.krimm@nasa.gov>

M. Stamatikos (OSU), 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), B. Mingo (U Leicester), 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 downlink,
we report further analysis of BAT GRB 160826A (trigger #709907)
(Mingo, et al., GCN Circ. 19866).  The BAT ground-calculated position is
RA, Dec = 183.120, -67.664 deg which is
    RA(J2000)  =  12h 12m 28.8s
    Dec(J2000) = -67d 39' 51.7"
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, rough FRED-like peak starting
at T+0 sec, peaking at about T+5 sec and decaying to near background by T+20 
sec.  This is followed by low-level emission out to about T+70 sec.
T90 (15-350 keV) is 52.6 +- 14.5 sec (estimated error including systematics).

The time-averaged spectrum from T+3.85 to T+61.58 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.54 +- 0.29.  The fluence in the 15-150 keV band is 4.9 +- 0.9 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+4.64 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/709907/BA/


GRB_name: GRB160824B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19873
SUBJECT: GRB 160824B: CALET Gamma-Ray Burst Monitor detection
DATE:    16/08/26 22:50:06 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

A. Yoshida, T. Sakamoto, Y. Kawakubo, M. Moriyama, Y. Yamada (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (JAXA), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long-duration GRB 160824B (Hamburg et al., GCN Circ. 19856;
INTEGRAL-SPI/ACS trigger #7538) triggered the CALET Gamma-ray Burst Monitor
(CGBM) at 14:21:12.34 on 24 August 2016.  The burst signal was seen by
all CGBM instruments.  Because of a problem in one of the ground alert processing
script, the GCN notice was not distributed automatically for this event.

The light curve of the SGM shows a single peak starting at T+0.5 sec, peaking at
T+1.5 sec and ending at T+4 sec.  The T90 duration measured by the SGM data
is 2.7 +- 0.1 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1156083685/

The CALET data used in this analysis are provided by the Waseda
CALET Operation Center located at the Waseda University.


GRB_name: GRB160827A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19876
SUBJECT: GRB 160827A: Swift detection of a burst
DATE:    16/08/27 15:54:29 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

K. L. Page (U Leicester) and S. D. Barthelmy (GSFC) report on behalf
of the Swift Team:

At 15:46:45 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160827A (trigger=710050).  Swift did not slew due to observing
constraint.  The BAT on-board calculated location is 
RA, Dec 179.296, -29.159, which is 
   RA(J2000)  =  11h 57m 11s
   Dec(J2000) = -29d 09' 32"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows multiple overlapping peaks
with a duration of about 30 sec.  The peak count rate
was ~1000 counts/sec (15-350 keV), at ~8 sec after the trigger. 

Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 00:09 UT on 2016 November 14. There will thus be no XRT
or UVOT data for this trigger before this time. 

Burst Advocate for this burst is K. L. Page (klp5 AT leicester.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: GRB160827A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19878
SUBJECT: GRB 160827A: Swift-BAT refined analysis
DATE:    16/08/27 22:23:49 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), K. L. Page (U Leicester), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU),
(i.e. the Swift-BAT team):
 
Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 160827A (trigger #710050)
(Page, et al., GCN Circ. 19876).  The BAT ground-calculated position is
RA, Dec = 179.274, -29.178 deg, which is 
   RA(J2000)  =  11h 57m 05.8s 
   Dec(J2000) = -29d 10' 40.9" 
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 48%.
 
The mask-weighted light curve shows a few olverlapping peaks starting
at ~T-5 sec, peaking at ~T+3 sec, and ending at ~T+13 sec.
T90 (15-350 keV) is 13.3 +- 2.2 sec (estimated error including systematics).
 
The time-averaged spectrum from T-5.81 to T+8.78 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.95 +- 0.25.  The fluence in the 15-150 keV band is 4.0 +- 0.7 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+2.49 sec in the 15-150 keV band
is 0.7 +- 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/710050/BA/


GRB_name: GRB160829A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19879
SUBJECT: GRB 160829A: Fermi-LAT detection of a short GRB
DATE:    16/08/29 17:28:47 GMT
FROM:    Judith Racusin at GSFC  <judith.racusin@nasa.gov>

J. L. Racusin (NASA/GSFC), G. Vianello (Stanford), D. Kocevski (NASA/GSFC), 
E. Bissaldi (Politecnico & INFN Bari), and R. Desiante (INFN Torino) 
report on behalf of the Fermi-LAT team:
At 08:01:37 on August 29, 2016 Fermi-LAT detected high-energy emission from 
GRB 160829A, which was also detected by Fermi-GBM (trigger 494150501/160829334). 
The best LAT on-ground location is found to be
RA, Dec = 201.7, -56.77 (degrees, J2000)
with an error radius of 0.12 deg (90% containment, statistical error only). 
This was 11 deg from the LAT boresight at the time of the trigger.
The data from the Fermi-LAT show an increase in the event rate within 10 deg of the 
GBM location after the GBM trigger that is spatially and temporally correlated with 
the GBM emission. 
The highest-energy photon is a 9.5 GeV event which is observed ~2 seconds after the 
GBM trigger, and the GRB is otherwise relatively faint, with only 3 photons (>100 MeV)
with a >90% probability of being associated with the burst. 
A Swift ToO has been requested for this burst.
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: GRB160829A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19880
SUBJECT: GRB 160829A: Swift ToO observations
DATE:    16/08/29 18:08:18 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 ToO observation of the Fermi/LAT GRB 160829A. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020687

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: GRB160816A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19881
SUBJECT: GRB 160816A, the review of the sky area in plate archives
DATE:    16/08/29 20:55:56 GMT
FROM:    Valentyna Golovnya at Main Astro Obs,Kyiv  <golov_v@ukr.net>

V.V. Golovnya, V.M. Andruk (Main Astro Obs., Kyiv) report: We have undertaken the review of the sky area in vicinity of GRB 160816A (Kennea J.A. et al., GCN 19806) on astronegatives, collected in Ukrainian NAS Main astronomical observatory plate archives (1976-1996). All the plates with the possible object appearance are digitized using Epson Expression 10000XL flatbed scanner and have been placed into Golosiiv Plate Archive database DBGPA with open access to them.         The list of plates is given in the table: YYYYMMDD/TimeUT --Plates--     Exp.    Bmag    Star USNO-A2 19 850822/212139 GUA040C000726  18.0    16.2    1200-18040986 19860712/234442 GUA040C000958  16.0    16.0    1200-18048101 19 860713/000658 GUA040C000959A 16.0    16.1    1200-18044684 19 860716/233422 GUA040C000967  16.0    16.6    1200-18046182 19 860716/235509 GUA040C000968A 16.0    16.6    1200-18046182 TimeUT â€“ T start of the maximum exposure; Plates - The plates archive identifier of DWA (D/F=40/200,M=103"/mm) GUA040C, of the Ukrainian NAS Main Astro obs, Marsden's number - 83) the plate number (http://gua.db.ukr-vo.org). Exp.  - Duration of the maximum exposure (minutes). Bmag  - Limited B mag, derived in the 6 minutes area around        the location GRB 160816A given in P.A. Evans (P. Evans http://www.swift.ac.uk/xrt_positions/00020685/):        RA(J2000)= 21h 29m 38.71s, Dec(J2000)= +37d 07' 58.3" Star USNO-A2 - Comparison star.  The preview images of 5 areas together with the 6 min.of arc area from Aladin can be found in http://gua.db.ukr-vo.org/img/grb/160816A/index.html. The images with full resolution are available via e-mail on demand. 


GRB_name: GRB160829A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19882
SUBJECT: GRB 160829A: Fermi GBM Detection
DATE:    16/08/29 23:09:05 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007@uah.edu>

R. Hamburg (UAH), C. Meegan (UAH), and O. Roberts (UCD)
report on behalf of the Fermi GBM Team:

"At 08:01:37.64 UT on 29 August 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160829 (trigger 494150501 / 160829334),
which was also detected by the LAT (Racusin et al. 2016, GCN 19879).

The GBM light curve consists of two short peaks
with a duration (T90) of about 0.5 s (50-300 keV).
The time-averaged spectrum from T0-0.06 s to T0+0.38 s is
best fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.56 +/- 0.24 and
the cutoff energy, parameterized as Epeak, is 771.40 +/- 282.00 keV

The event fluence (10-1000 keV) in this time interval is
(5.12 +/- 0.49)E-07 erg/cm^2. The 0.064-sec peak photon flux measured
starting from T0+0.00 s in the 10-1000 keV band
is 5.3 +/- 0.9 ph/s/cm^2.

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


GRB_name: GRB160829A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19883
SUBJECT: GRB 160829A: Swift-XRT observations
DATE:    16/08/30 09:16:42 GMT
FROM:    Andy Beardmore at U Leicester  <ab271@leicester.ac.uk>

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), S.L. Gibson (U. Leicester), 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 160829A (Racusin et al. GCN Circ. 19879),
collecting 4.8 ks of Photon Counting (PC) mode data between T0+37.4 ks
and T0+61.4 ks. 

No X-ray source has been detected within the LAT error region (Racusin
et al. GCN Circ. 19879), with a 3 sigma upper limit count rate of
2.6e-3 ct/s (0.3-10keV). 

An uncatalogued X-ray source was detected 13.3 arcmin from the LAT
position at a count rate of (4.9 +/- 1.9)e-3 ct/s. This source is
identified by SIMBAD as CD-56 4975 at RA, Dec (J2000) = 13h 28m 03.68s,
-56d 54m 30.38s, whose colours are suggestive of a late-type star,
which is, therefore, unlikely to be related to the LAT burst.

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/00020687.

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


GRB_name: GRB160824B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19884
SUBJECT: GRB 160824B: Lomonosov BDRG gamma ray detection and MASTER limit 
DATE:    16/08/31 16:28:04 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

  N.L.Dzhioeva, A.M.Amelushkin, V.O.Barinova, A.V.Bogomolov, V.V.Bogomolov, 
A.F.Iyudin, V.V.Kalegaev, M.I.Panasyuk, V.L. Petrov, S.I.Svertilov, 
I.V.Yashin
Physics Department, Skobel'tsyn Institute of Nuclear Physics, Moscow State 
University.

I. Park, J. Lee, S. Jeong
Department of Physics, Sungkyunkwan University, Seobu-ro, Jangangu, Suwonsi, 
Korea

V. Lipunov, E.S. Gorbovskoy,   N.Tyurina, 
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

V.Yurkov, Yu.Sergienko, A.Gabovich
Blagoveschensk Educational State University, Blagoveschensk

Fermi GRB 160824B (Hamburg, GCN 19856; Yoshida et al., GCN 19873) was 
observed by Lomonosov on 16/08/24 around Fermi/CALET trigger time.

It was visible by all 3 detectors of BDRG  in energy range up to 1 MeV.
The parameters of GRB are:

Total duration ~3s.
Peak intensity in the range 20-1000 keV  >6 photons/cm2*s in the range 20-1000 keV
Peak intensity  in the range 250-1000 keV >2 photons/cm2*s

The Gamma Ray light curve is available at 
http://master.sai.msu.ru/static/GRB160824B_Lomonosov_BDRG.png


MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in Tunka was pointed to the  GRB160824B  (Hamburg et al, GCN 
19856) 62 sec after notice time and 107 sec after trigger time at 
2016-08-24 14:23:00 UT. On our first (20s exposure)  set we  found 56 
optical transient within FERMI error-box (ra=08 21 12 dec=+46 14 00 
r=3.833300) brighter then 15.83, but first alert   have a too large 
coordinate error and this region  is outside final error box.  We cover 
part of final error box 619 sec after trigger time at 2016-08-24 14:31:32 
UT by 3-th alert message. The 5-sigma upper limit has been about 18 mag on 
120 s exposure image. No OT was found.


MASTER II  robotic telescope located in Blagoveschensk  was starded 
inspect inside  the  GRB160824B  (Hamburg et al, GCN 19856, Yoshida et al, 
GCN 19873) error box  1165  sec after trigger time at 2016-08-24 14:40:38 
UT.  We cover full 1 sigma + 3 degree systematic error box with  5-sigma 
upper limit  about 18 mag. 
No OT was found.

The cover map is available at 
http://master.sai.msu.ru/static/GRB160824B_MASTER_Cover.png  .

  The message may be cited.


GRB_name: GRB160905A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19887
SUBJECT: GRB 160905A: Swift detection of a burst with an optical counterpart
DATE:    16/09/05 11:31:37 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

P. D'Avanzo (INAF-OAB), A. P. Beardmore (U Leicester),
A. A. Breeveld (UCL-MSSL), D. N. Burrows (PSU),
P.A. Evans (U Leicester), J. A. Kennea (PSU),
N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC),
P. T. O'Brien (U Leicester), D. M. Palmer (LANL) and
B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team:

At 11:18:58 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160905A (trigger=711084).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 162.237, -50.800 which is 
   RA(J2000) = 10h 48m 57s
   Dec(J2000) = -50d 47' 59"
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 50 sec.  The peak count rate
was ~13000 counts/sec (15-350 keV), at ~18 sec after the trigger. 

The XRT began observing the field at 11:19:56.0 UT, 57.7 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 162.2448, -50.8014 which is equivalent to:
   RA(J2000)  = +10h 48m 58.75s
   Dec(J2000) = -50d 48' 05.0"
with an uncertainty of 4.8 arcseconds (radius, 90% containment). This
location is 18 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 6.05e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 66 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 10:48:59.18 = 162.24658
  DEC(J2000) = -50:48:04.3  = -50.80120
with a 90%-confidence error radius of about 0.61 arc sec. This position is 4.1
arc sec. from the center of the XRT error circle. The estimated magnitude is
15.88 with a 1-sigma error of about  0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.46. 

Burst Advocate for this burst is P. D'Avanzo (paolo.davanzo 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: GRB160905A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19889
SUBJECT: GRB 160905A: Fermi GBM observation
DATE:    16/09/05 18:51:54 GMT
FROM:    Elisabetta Bissaldi at U.Innsbruk/IAPP  <Elisabetta.Bissaldi@uibk.ac.at>

E. Bissaldi (Politcenico & INFN Bari)
reports on behalf of the Fermi GBM Team:

"At 11:18:55.91 UT on 5 September 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160905A (trigger 494767139 / 160905471),
which was also detected by the Swift/BAT (D'Avanzo et al. 2016, GCN 19887).
The GBM on-ground location is consistent with the Swift position.

The trigger resulted in an Autonomous Repoint Request (ARR)
by the GBM Flight Software owing to the high peak flux of the GRB.
This ARR was accepted and the spacecraft slewed to the GBM in-flight
location. The initial angle from the Fermi LAT boresight to
the GBM ground location is 18 degrees.

The GBM light curve consists of two peaks
with a duration (T90) of about 34 s (50-300 keV).
The time-averaged spectrum from T0 to T0+40 s is
adequately fit by a Band function with Epeak = 830  30 keV,
alpha = -0.77  0.01, and beta = -2.43  0.09.

The event fluence (10-1000 keV) in this time interval is
(9.0  0.1)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+20 s in the 10-1000 keV band
is 16.2  0.3 ph/s/cm^2.

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


GRB_name: GRB160905A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19890
SUBJECT: GRB 160905A: Fermi-LAT detection
DATE:    16/09/05 19:11:35 GMT
FROM:    Julie McEnery at NASA/GSFC  <julie.e.mcenery@nasa.gov>

J. E. McEnery (NASA/GSFC), F. Longo (University & INFN Trieste),
E. Bissaldi (Politecnico & INFN Bari) and D. Kocevski (NASA/GSFC)
report on behalf of the Fermi-LAT team:

At 11:18:55.91 on September, 05, 2016 Fermi-LAT detected
high-energy emission from GRB 160905*A*, which was also
detected by Swift (GCN 19887) and Fermi-GBM
(trigger 494767139/160905471; GCN 19889).

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 best LAT on-ground location is found to be
RA, Dec = 162.02, -50.88 (J2000)
with an error radius of 0.08 deg (90 % containment, statistical error 
only).

This was 18 deg from the LAT boresight at the time of the trigger.

The highest-energy photon is a *8 GeV* event which was
observed *350* seconds after the GBM trigger.

The Fermi-LAT point of contact for this burst is *
Dan Kocevski (daniel.kocevski@nasa.gov <mailto:daniel.kocevski@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: GRB160905A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19891
SUBJECT: GRB 160905A: Enhanced Swift-XRT position
DATE:    16/09/05 19:16:19 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 854 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 160905A, 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 = 162.24585, -50.80095 which is equivalent
to:

RA (J2000): 10h 48m 59.00s
Dec (J2000): -50d 48' 03.4"

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: GRB160816A
Detection_method: Fermi LAT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19892
SUBJECT: GRB 160816A: Possible radio afterglow detection at 15 GHz with AMI
DATE:    16/09/05 20:21:51 GMT
FROM:    Kunal Mooley at Oxford U  <kunal.mooley@physics.ox.ac.uk>

K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson 
(Curtin), T. Cantwell (Manchester), C. Rumsey, D. Titterington, S. H. 
Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), 
K. Grainge, A. Scaife (Manchester)

We observed the Fermi/LAT GRB 160816A (Racusin et al., GCN 19802) with 
the AMI Large Array at 15 GHz on 2016 Aug 18.02, Aug 19.06, and Sep 
03.02 (UT) as part of the 4pisky program. We detect a possible radio 
afterglow (consistent with the XRT location; Kennea et al., GCN 19806) 
in the second epoch with a peak flux density of 129+/-32 uJy, and 3sigma 
upper limits of 111 uJy and 168 uJy in the first and third epochs 
respectively.

We thank the AMI staff for scheduling these observations. The AMI-GRB 
database is a log of all GRB follow up observations with the AMI, and is 
available at http://4pisky.org/ami-grb/.


GRB_name: GRB160821A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19893
SUBJECT: GRB 160821A: 15 GHz upper limits from AMI
DATE:    16/09/05 20:24:20 GMT
FROM:    Kunal Mooley at Oxford U  <kunal.mooley@physics.ox.ac.uk>

K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson 
(Curtin), T. Cantwell (Manchester), D. Titterington, S. H. Carey, J. 
Hickish, Y. C. Perrott, N. Razavi-Ghods, C. Rumsey, P. Scott 
(Cambridge), K. Grainge, A. Scaife (Manchester)

The AMI Large Array triggered on the Swift alert for GRB 160821A (Siegel 
et al., GCN 19830) as part of the 4pisky program, and subsequent follow 
up observations were obtained up to 10 days post-burst. Our observations 
at 15 GHz on 2016 Aug 22.55, Aug 23.56, Aug 25.56, and Aug 29.56 (UT) do 
not reveal any transient radio source within the BAT error circle 
(Markwardt et al., GCN 19840), with 3sigma upper limits of 87 uJy, 108 
uJy, 108 uJy, and 102 uJy respectively.

We thank the AMI staff for scheduling these observations. The AMI-GRB 
database is a log of all GRB follow up observations with the AMI, and is 
available at http://4pisky.org/ami-grb/.


GRB_name: GRB160905A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19894
SUBJECT: GRB 160905A: Swift-XRT refined Analysis
DATE:    16/09/06 00:07:58 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. Melandri (INAF-OAB), D.N. Burrows (PSU), T.G.R. Roegiers (PSU), L.M.
McCauley (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester),
B. Mingo (U. Leicester), V. D'Elia (ASDC) and P. D'Avanzo report on
behalf of the Swift-XRT team:

We have analysed 7.2 ks of XRT data for GRB 160905A (D'Avanzo et al.
GCN Circ. 19887), from 50 s to 29.8 ks after the  BAT trigger. The data
comprise 2.2 ks 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 Osborne et
al. (GCN Circ. 19891).

The late-time light curve (from T0+5.6 ks) can be modelled with a
series of power-law decays. The initial decay index is alpha=0.5 (+0.6,
-0.4). At T+7998 s  the decay steepens to an alpha of 7.92 (+0.08,
-5.15). The light curve breaks again at T+9660 s to a decay with
alpha=-1.5 (+0.0, -0.4),  before a final break at T+15.0 ks s after
which the decay index is 1.0 (+/-0.3).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.729 (+/-0.024). The
best-fitting absorption column is  4.89 (+0.18, -0.17) x 10^21 cm^-2,
in excess of the Galactic value of 3.8 x 10^21 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.84 (+0.12, -0.11)
and a best-fitting absorption column of 5.9 (+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 4.7 x 10^-11 (7.1 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      5.9 (+0.9, -0.8) x 10^21 cm^-2
Galactic foreground: 3.8 x 10^21 cm^-2
Excess significance: 4.4 sigma
Photon index:      1.84 (+0.12, -0.11)

If the light curve continues to decay with a power-law decay index of
1.0, the count rate at T+24 hours will be 0.10 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.7 x
10^-12 (7.1 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/00711084.

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


GRB_name: GRB160905A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19896
SUBJECT: GRB 160905A: Swift-BAT refined analysis
DATE:    16/09/06 02:51:10 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), P. D'Avanzo (INAF-OAB),
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-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 160905A (trigger #711084)
(D'Avanzo, et al., GCN Circ. 19887).  The BAT ground-calculated position is
RA, Dec = 162.249, -50.803 deg which is
    RA(J2000)  =  10h 48m 59.7s
    Dec(J2000) = -50d 48' 09.2"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 98%.

The mask-weighted light curve shows a bright main episode with several
overlapping peaks starting at ~T-10 sec, peaking at ~T+10 sec and ending
at ~T+25 sec.  The additional peak is seen starting at ~T+30 sec, peaking
at ~T+35 sec and ending at ~T+40 sec.  The further weak extended emission
is visible up to ~T+180 sec.  T90 (15-350 keV) is 64 +- 16 sec (estimated
error including systematics).
  
The time-averaged spectrum from T-15.2 to T+96.8 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.04 +- 0.03.  The fluence in the 15-150 keV band is 1.50 +- 0.02 x 10^-5 erg/cm2.
The 1-sec peak photon flux measured from T+8.30 sec in the 15-150 keV band
is 6.3 +- 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/711084/BA/


GRB_name: GRB160905A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19897
SUBJECT: GRB 160905A: Swift/UVOT Detection
DATE:    16/09/06 10:55:43 GMT
FROM:    Sam Emery at MSSL-UCL  <samuel.emery.15@ucl.ac.uk>

S.W.K. Emery (UCL-MSSL) and P. D'Avanzo (INAF-OAB)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 160905A
67 s after the BAT trigger (D'Avanzo et al., GCN Circ. 19887), which was
also detected by Fermi-GBM (GCN 19889) and Fermi-LAT (GCN 19890).
A fading source consistent with the XRT position
(Osborne et al. GCN Circ. 19891) 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          67           216          147         15.8  0.03
white                 67         2234          469         17.1  0.05
u_FC              280           530          246         18.3  0.15
u                      280         2185          401         18.8  0.16
v                      610         2285          195         17.4  0.12
b                      536         2210          175         18.7  0.16
w1                   660         2160          175         >19.1
m2                   635         2296          162         >19.1
w2                   586         2260          195         >19.4

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.45 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB160821B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19898
SUBJECT: GRB 160821B: 15 GHz upper limits from AMI
DATE:    16/09/06 15:24:11 GMT
FROM:    Kunal Mooley at Oxford U  <kunal.mooley@physics.ox.ac.uk>

K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson 
(Curtin), T. Cantwell (Manchester), D. Titterington, S. H. Carey, J. 
Hickish, Y. C. Perrott, N. Razavi-Ghods, C. Rumsey, P. Scott 
(Cambridge), K. Grainge, A. Scaife (Manchester)

We observed the short GRB 160821B (Siegel et al., GCN 19833) with the 
AMI Large Array as part of the 4pisky program. The observations at 15 
GHz on 2016 Aug 22.85, Aug 23.82, Aug 25.83, and Sep 03.83 (UT) do not 
reveal any radio source at the VLA location (Fong et al., GCN 19854), 
with 3sigma upper limits of 138 uJy, 227 uJy, 129 uJy, and 171 uJy 
respectively.

We note that, due to power outage, the AMI-LA did not trigger 
robotically, and could only obtain the first observation 22 hours 
post-burst. This is several hours after the VLA 6 GHz detection (~3.6 
hours post-burst).

We thank the AMI staff for scheduling these observations. The AMI-GRB 
database is a log of all GRB follow up observations with the AMI, and is 
available at http://4pisky.org/ami-grb/.


GRB_name: GRB160824A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19899
SUBJECT: GRB 160824A: 15 GHz upper limits from AMI
DATE:    16/09/06 15:26:44 GMT
FROM:    Kunal Mooley at Oxford U  <kunal.mooley@physics.ox.ac.uk>

K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson 
(Curtin), T. Cantwell (Manchester), D. Titterington, S. H. Carey, J. 
Hickish, Y. C. Perrott, N. Razavi-Ghods, C. Rumsey, P. Scott 
(Cambridge), K. Grainge, A. Scaife (Manchester)

The AMI Large Array robotically triggered on the Swift alert for GRB 
160824A (Evans et al., GCN 19855) as part of the 4pisky program, and 
subsequent follow up observations were obtained up to 10 days 
post-burst. Our observations at 15 GHz on 2016 Aug 25.11, Aug 26.27, Aug 
28.29, and Sep 01.29 (UT) do not reveal any radio source at the XRT 
location (Goad et al., GCN 19857), with 3sigma upper limits of 444 uJy, 
126 uJy, 117 uJy, and 117 uJy respectively.

We thank the AMI staff for scheduling these observations. The AMI-GRB 
database is a log of all GRB follow up observations with the AMI, and is 
available at http://4pisky.org/ami-grb/.


GRB_name: GRB160905A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19900
SUBJECT: Konus-Wind observation of GRB 160905A
DATE:    16/09/06 16:15:22 GMT
FROM:    Anastasia Tsvetkova at Ioffe Institute  <tsvetkova@mail.ioffe.ru>

A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks, P. Oleynik,
M. Ulanov, D. Svinkin, A. Lysenko, A. Kozlova and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration, hard-spectrum GRB 160905A (Swift-BAT trigger #711084:
D'Avanzo et al., GCN 19887; Barthelmy et al., GCN 19896;
Fermi GBM observation: Bissaldi, GCN 19889;
Fermi-LAT detection: McEnery et al., GCN 19890)
triggered Konus-Wind at T0=40735.196 s UT (11:18:55.196).

The burst light curve shows a double-peaked structure with a total 
duration of ~44 s.
The emission is seen up to ~10 MeV.

As observed by Konus-Wind, the burst
had a fluence of 1.50(-0.11,+0.11)x10^-4 erg/cm2,
and a 64-ms peak energy flux, measured from T0+10.224 s,
of 1.17(-0.23,+0.23)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+42.240 s)
is best fit in the 20 keV - 18 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.70(-0.05,+0.06),
the high energy photon index beta = -2.39(-0.26,+0.16),
the peak energy Ep = 594(-50,+56) keV,
chi2 = 124/97 dof.

The spectrum near the peak count rate
(measured from T0+7.424 to T0+12.288 s)
is best fit in the 20 keV - 18 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.65(-0.08,+0.09),
the high energy photon index beta = -2.53(-0.44,+0.25),
the peak energy Ep = 664(-81,+88) keV,
chi2 = 96/83 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB160905_T40735/

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


GRB_name: GRB160910A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19901
SUBJECT: GRB 160910A: Fermi GBM observation
DATE:    16/09/11 01:49:14 GMT
FROM:    Peter Veres at UAH  <veresp@gmail.com>

P Veres (UAH) and C Meegan (UAH) report on behalf of the Fermi GBM Team:

"At 17:19:39.15 UT on 10 September 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160910A (trigger 495220783 / 160910722).

The on-ground calculated location, using the GBM trigger data, is RA =
221.8, DEC = 39.6 (J2000 degrees, equivalent to 14 h 47 m, 39 d 38 '), with
an uncertainty of 1 degrees (radius, 1-sigma containment, statistical only;
there is additionally a systematic error which we have characterized as a
core-plus-tail model, with 90% of GRBs having a 3.7 deg error and a small
tail suffering a larger than 10 deg systematic error. [Connaughton et al.
2015, ApJS, 216, 32] ).

The trigger resulted in an Autonomous Repoint Request (ARR) by the GBM
Flight Software owing to the high peak flux of the GRB. This ARR was
accepted and the spacecraft slewed to the GBM in-flight location. The
initial angle from the Fermi LAT boresight to the GBM ground location is 71
degrees.

The GBM light curve shows a single pulse with a duration (T90) of about
24.3 s (50-300 keV). The time-averaged spectrum from T0 to T0+32.3 s is
best fit by a Band function with Epeak = 347 +/- 9 keV, alpha = -0.78 +/-
0.01, and beta = -2.23 +/- 0.04.

The event fluence (10-1000 keV) in this time interval is (8.41 +/- 0.06)E-5
erg/cm^2. The 1-sec peak photon flux measured starting from T0+8.2 s in the
10-1000 keV band is 76.5 +/- 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: GRB160910A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19902
SUBJECT: GRB 160910A: Fermi-LAT detection
DATE:    16/09/11 02:07:29 GMT
FROM:    Judith Racusin at GSFC  <judith.racusin@nasa.gov>

J. L. Racusin (NASA/GSFC) and D. Kocevski (NASA/GSFC) report on behalf of the Fermi-LAT team: 

At 17:19:39 on September 10, 2016 Fermi-LAT detected high-energy emission from GRB 160910A, which was also detected by Fermi-GBM (trigger 495220782/160910722; Veres et al. GCN #19901). 

The best LAT on-ground location is found to be
RA, Dec = 221.26, 38.76 (J2000)
with an error radius of 0.35 deg (90 % containment, statistical error only). 

The GBM location was initially at the edge of the LAT field of view at an angle of 71 degrees to the LAT boresight and triggered an autonomous repoint of the spacecraft.  The highest-energy photon is a 500 MeV event which is observed 9 ks after the GBM trigger.

A Swift ToO has been requested for this burst.

The Fermi-LAT point of contact for this burst is Dan Kocevski (daniel.kocevski@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: GRB160908A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19903
SUBJECT: GRB 160908A: CALET Gamma-Ray Burst Monitor detection
DATE:    16/09/11 11:55:45 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

T. Sakamoto, A. Yoshida, Y. Kawakubo, M. Moriyama, Y. Yamada (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (JAXA), I. Takahashi (IPMU), Y. Asaoka,
S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), W. Ishizaki (ICRR),
M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long-duration GRB 160908A (Konus-Wind trigger time on 05:17:01.127;
INTEGRAL-SPI/ACS trigger #7558) triggered the CALET Gamma-ray Burst Monitor
(CGBM) at 05:17:00.07 on 8 September 2016.  The burst signal was seen by
all CGBM instruments.  Please note that the trigger time reported on the GCN CALET
GBM Flight Lightcurve notice, 05:17:00.74 UT, was wrongly reported due to the real-time
pipeline issue.  The correct trigger time is 05:17:00.07 UT.

The light curve of the SGM shows four peaks.  The whole burst emission
starts at T-5 sec and ends at T+40 sec.  The four spikes peak at T+8 sec,
T+16 sec, T+26 sec and T+41 sec.  The T90 duration measured by the SGM data
is 36.2 +- 5.1 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1157347009/

The CALET data used in this analysis are provided by the Waseda
CALET Operation Center located at the Waseda University.


GRB_name: GRB160910A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19904
SUBJECT: GRB 160910A: Swift-XRT afterglow detection
DATE:    16/09/11 15:04:50 GMT
FROM:    Antonino D'Ai at IASF-PA  <antonino.dai@ifc.inaf.it>

A. D'A  (INAF-IASFPA), V. D'Elia (ISDC), J. Cummings (GSFC/UMBC),
B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), T.G.R. Roegiers (PSU),
S.L. Gibson (U. Leicester), 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/GBM (Veres 
et al., GCN Circ. 19901)
and Fermi/LAT (Racusin et al., GCN Circ. 19902) detected burst GRB 
160910A in a series of 4 observations
tiled on the sky. The total exposure time is 5 ks, distributed over 4 
tiles.
The data were collected between T0+35 ks and T0+47 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.=221.4423, 39.0668 which is 
equivalent to:

RA (J2000)   = 14h45m46.16s
Dec (J2000) = +39:04:00.64

with an uncertainty of 4.3 arcsec (radius, 90% confidence).
This position is 0.34 deg from the Fermi/LAT position and 0.6 deg from 
the GBM position.
The light curve built with the data collected so far is consistent with 
a constant source of mean
count rate (1.0 +/- 0.1)e-01 ct/sec. More data are required to search 
for a fading behaviour.

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.7 (+0.6, -0.6).
The best-fitting absorption column is  1.3 (+1.7, -1.3) x 10^21 cm^-2,
consistent with the Galactic value of 1.0 x 10^20 cm^-2 (Willingale et 
al. 2013).
The [absorbed] unabsorbed 0.3-10 keV flux is 5.1 (+1.6, -1.0)e^-10 erg 
cm^-2 s^-1 [4.7 (+2.1, -1.3) e-10 erg cm^-2 s^-1].

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


GRB_name: GRB160910A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19905
SUBJECT: GRB 160910A: Tiled Swift observations
DATE:    16/09/11 15:30:11 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>


[GCN OPS NOTE(11sep2016) Per author's request 19905 was removed from the archive.]


GRB_name: GRB160910A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19906
SUBJECT: GRB 160910A: Tiled Swift observations
DATE:    16/09/11 17:19:16 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 series of observations, tiled on the sky, of the
Fermi/LAT GRB 160910A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00059

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 Fermi/LAT 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.

[GCN OPS NOTE(12sep16): Per author's request, the "B" in the GRB name
was changed to an "A"; Subject-line and in the first paragraph.]


GRB_name: GRB160910A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19907
SUBJECT: GRB 160910A: Afterglow detection from OSN
DATE:    16/09/11 20:56:28 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), L. Izzo (IAA-CSIC), 
D.A. Kann (TLS Tautenburg), V. Casanova (IAA-CSIC) report on 
behalf of a larger collaboration:

We have observed the field of GRB 160910A (Veres et al. GCN 19901, 
Racusin et al. GCN 19902, Dâ€™AÃ¬ et al. GCN 19904) with the 1.5m 
OSN telescope in Granada (Spain). The observation consisted of I-band 
imaging and started at 20:15:07 (26.92 hr after the burst). On the first 300 s
image we detect an object within the XRT error box at I(AB) ~ 19.3 mag, 
not present in the SDSS images, which we identify as the counterpart of 
GRB 160910A

We encourage further follow-up and spectroscopy of this bright afterglow.


GRB_name: GRB160910A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19908
SUBJECT: GRB 160910A: NOT afterglow confirmation
DATE:    16/09/11 21:03:05 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>

D. Malesani (DARK/NBI and DTU Space), D. Xu (NAOC/CAS), A. de Ugarte 
Postigo (IAA-CSIC and DARK/NBI), R. Tronsgaard Rasmussen (NOT), P. Blay 
(NOT/IAC), report on behalf of a larger collaboration.

We observed the field of the Fermi GRB 160910A (Veres & Meegan, GCN 
19901; Racusin & Kocevski, GCN 19902) with the Nordic Optical Telescope 
(NOT) equipped with the AlFOSC imaging camera.

Observations started on 2016 Sep 11.847 UT, and consisted of 3x300 s in 
the SDSS r filter. We detect the afterglow reported by de Ugarte Postigo 
et al. (GCN 19907), and we provide coordinates (J2000):

RA = 14:45:46.04
Dec = +39:04:00.2

The expected uncertainty is <0.5". Comparing with nearby SDSS stars, we 
measure for the afterglow a magnitude r = 19.65 +- 0.01 (AB) at a mean 
time of Sep 11.8487 UT (27.04 hr after the GRB trigger).


GRB_name: GRB160910A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19909
SUBJECT: GRB 160910A: CALET Gamma-Ray Burst Monitor detection
DATE:    16/09/12 03:42:09 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

Y. Kawakubo, A. Yoshida, T. Sakamoto, M. Moriyama, Y. Yamada (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (JAXA), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu,
T. Tamura (Kanagawa U), W. Ishizaki (ICRR), M. L. Cherry (LSU),
S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long-duration GRB 160910A (Veres et al., GCN Circ. 19901; Racusin et al.,
GCN Circ. 19902;  INTEGRAL-SPI/ACS trigger #7560) triggered the CALET
Gamma-ray Burst Monitor (CGBM) at 17:19:41.25 on 10 September 2016.
The burst signal was seen by all CGBM instruments.

The light curve of the SGM shows an initial weak peak followed by a main
bright peak.  The weak initial peak starts at T0, peaks at T+3 sec and ends
at T+4 sec.  The main bright peak starts at T+4 sec, peaks at T+6 sec and
ends at T+20 sec.  Several overlapping pulses are evident in the main peak.
The T90 duration measured by the SGM data is 20.7 +- 1.5 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1157563166/

The CALET data used in this analysis are provided by the Waseda
CALET Operation Center located at the Waseda University.


GRB_name: GRB160910A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19910
SUBJECT: GRB 160910A: XRT results and corrections to GCN 19905 & 19906
DATE:    16/09/12 07:29:43 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:

Due to technical issues, GCN 19905 was issues with an incorrect encoding 
and GCN 19906 was contained the wrong name and URL.

Swift-XRT observed the field of GRB 160910A and discovered an afterglow 
as reported by D'Ai et al (GCN Circ. 19904). As the afterglow has been 
detected, the full XRT results for the GRB are available at 
http://www.swift.ac.uk/xrt_products/00020695

Analysis of the entire tiled campaign is at
http://www.swift.ac.uk/xrt_products/TILED_GRB00058/


GRB_name: GRB160910A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19911
SUBJECT: GRB 160910A: Correction to GCN 19904
DATE:    16/09/12 09:03:37 GMT
FROM:    Antonino D'Ai at IASF-PA  <antonino.dai@ifc.inaf.it>

A. D'A reports on behalf of the Swift/XRT team: the reported
absorbed/unabsorbed fluxes in GCN 19904 have been incorrectly reported.
The correct information is:

"The [absorbed] unabsorbed 0.3-10 keV flux is 5.6 (+1.4, -1.2) x 10^-12
erg  cm^-2 s^-1 [4.9 (+1.9, -1.4) x 10^-12 erg cm^-2 s^-1]."

We thank M. De Pasquale for spotting the mistake.
We apologize for any confusion.


GRB_name: GRB160912A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19912
SUBJECT: GRB 160912A: Swift detection of a burst
DATE:    16/09/12 16:39:36 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

J. K. Cannizzo (NASA/UMBC), S. D. Barthelmy (GSFC),
A. A. Breeveld (UCL-MSSL), D. N. Burrows (PSU), A. D'Ai (INAF-IASFPA),
V. D'Elia (ASDC), S. W. K Emery (UCL-MSSL), J. A. Kennea (PSU),
N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC),
B. Mingo (U Leicester), K. L. Page (U Leicester) and
M. H. Siegel (PSU) report on behalf of the Swift Team:

At 16:07:43 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160912A (trigger=711914).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 301.518, +57.543, which is 
   RA(J2000)  =  20h 06m 04s
   Dec(J2000) = +57d 32' 36"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  As is typical for image triggers, the BAT light curve
does not show anything significant over the trigger window.  However, at ~T+150 sec
there is a flare in the light curve (~1300 cnts/sec). 

The XRT began observing the field at 16:09:57.0 UT, 134.0 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source with an enhanced position: RA, Dec 301.4981,
57.5655 which is equivalent to:
   RA(J2000)  = 20h 05m 59.56s
   Dec(J2000) = +57d 33' 55.8"
with an uncertainty of 2.1 arcseconds (radius, 90% containment). This
location is 89 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 note the presence in the XRT raw light curve of a large X-ray flare 
coincident with the BAT flare mentioned above. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 2.35
x 10^21 cm^-2 (Willingale et al. 2013). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 137 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The 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
0.20. 

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


GRB_name: GRB160910A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19913
SUBJECT: Konus-Wind observation of GRB 160910A
DATE:    16/09/12 17:19:40 GMT
FROM:    Anastasia Tsvetkova at Ioffe Institute  <tsvetkova@mail.ioffe.ru>

A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks, P. Oleynik,
M. Ulanov, D. Svinkin, A. Lysenko, A. Kozlova and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration, very intense GRB 160910A
(Fermi GBM observation: Veres & Meegan, GCN 19901;
Fermi-LAT detection:  Racusin & Kocevski, GCN 19902;
CALET Gamma-Ray Burst Monitor detection: Kawakubo et al., GCN 19909)
triggered Konus-Wind at T0=62379.089 s UT (17:19:39.089).

The burst light curve starts with an initial weaker emission followed by
a main bright peak with a duration of ~50 s.
The main pulse is followed by a long weak tail seen up to ~T0+150 s.
The emission is seen up to ~10 MeV.

As observed by Konus-Wind, the burst
had a fluence of 1.36(-0.09,+0.10)x10^-4 erg/cm2,
and a 64-ms peak energy flux, measured from T0+5.120 s,
of 3.51(-0.32,+0.32)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+47.872 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 = -0.81(-0.06,+0.07),
the high energy photon index beta = -2.16(-0.12,+0.09),
the peak energy Ep = 315(-29,+31) keV,
chi2 = 97/98 dof.

The spectrum near the peak count rate
(measured from T0+4.864 to T0+6.400 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 = -0.15(-0.10,+0.10),
the high energy photon index beta = -2.27(-0.09,+0.07),
the peak energy Ep = 266(-19,+21) keV,
chi2 = 100/69 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB160910_T62379/

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


GRB_name: GRB160910A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19914
SUBJECT: GRB 160910A: Global MASTER Net OT detection before LAT alert
DATE:    16/09/12 19:16:03 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

R. Rebolo, M. Serra Ricart, N. Lodieu, G. Israelian
The Instituto de Astrofisica de Canarias

K.Ivanov, O.Gres, N.M.Budnev, S.Yazev,
Irkutsk State University

A. Tlatov, V.Senik, D. Dormidontov, A.Parkhomenko
Kislovodsk Solar Station of the Pulkovo Observatory

V.Yurkov, Yu.Sergienko, A.Gabovich
Blagoveschensk Educational State University, Blagoveschensk

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

R.Podesta, C.Lopez, F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA)


MASTER-SAAO  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in SAAO was pointed to the FERMI GBM  GRB160910.72 15 sec after 
notice time and 65 sec after trigger time at 2016-09-10 17:20:45 UT.

On our first (20s exposure started 75 sec after GBM trigger)  set we do 
not found  optical transient within  FERMI error-box (ra=14 54 00 
dec=+39 23 00 r=3.41, trigger 495220783 / 160910722
(Veres  and  C.Meegan, GCN 19901)) because very low 
altitude on horizont ~3 degrees (one tube was under the roof).

Fortunatelly, we saw OT by one of two MASTER Very Wide Field Cameras (5 
sec expositon, 0.25 sec readout) .
On MASTER-SAAO VWF Camera  we see OT at 3 sigma confidence level with 
magnitude 11.6 +- 0.5 mag on a co-added images with total exposure 95 
seconds  (19 x 5 sec) starting at 17:20:45 i.e. 65 sec after trigger time. Mean 
time is 113 sec after trigger.

On our second MASTER-SAAO (30s 
exposure)  set started at 2016-09-10 17:22:26 (167 sec after trigger time) 
we  found OT  within FERMI error-box  with unfileterd
magnitide m = 11.6+-0.1 . The second exposition was making after receiving 
new Fermi GBM coordinates.

Ra, Dec  =  14h 45m 46.03s   +39d 04m 00.52s
err = +-0.5 arcsec

(cf.  A. D'A. et al., GCN 19904; A. de Ugarte Postigo et al., 19907; 
Malesani et al., GCN 19908 )

MASTER-IAC  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in IAC was starting survey on the FERMI GBM  GRB160910.72 
error-box  (ra=14 46 14 dec=+39 25 10 r=1.0)  11142 sec after notice time 
and 11239 sec after trigger time at 2016-09-10 20:26:58 UT. The 5-sigma upper 
limit on our first (60s exposure)  set is about 18.3 mag .  The OT 
unfiltered magnitude is 17.4+-0.4 .


The light curve is available at
http://master.sai.msu.ru/static/GRB160910A.png


The MASTER-SAAO power law index  alpha  = 1.30+-0.07 ( I ~ t^-alpha) in 
agreement with MASTER-IAC and some 
contradiction with late point (Malesani  et al., GCN 19908 )

The MASTER-SAAO and NOT combined   power law index  alpha  = 
1.17+-0.02 .


All MASTER observations was done  before LAT alert.


The message may be cited.


GRB_name: GRB160912A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19915
SUBJECT: GRB 160912A: Enhanced Swift-XRT position
DATE:    16/09/12 22:09:05 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 1795 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 160912A, 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 = 301.49915, +57.56557 which is equivalent
to:

RA (J2000): 20h 05m 59.80s
Dec (J2000): +57d 33' 56.0"

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: GRB160912A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19916
SUBJECT: GRB 160912A: Fermi GBM detection
DATE:    16/09/13 03:23:00 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007@uah.edu>

R. Hamburg (UAH)
reports on behalf of the Fermi GBM Team:

"At 16:10:11.39 UT on 12 September 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160912A (trigger 495389415 / 160912674).

This burst was also detected by the Swift BAT approximately
150 s after the Swift trigger time and reported as an x-ray flare
approximately 89 arcseconds from the BAT onboard position
(Cannizzo et al. 2016, GCN 19912). At the time of the Swift trigger,
the source was occulted by the Earth for Fermi.
The GBM on-ground location is consistent with the Swift position.

The GBM light curve consists of multiple peaks
with a duration (T90) of about 48 s (10-1000 keV).
The time-averaged spectrum from T0-4 s to T0+42 s is
best fit by a simple power law function with index -1.48 +/- 0.03.

The event fluence (10-1000 keV) in this time interval is
(6.1 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+8.4 s in the 10-1000 keV band
is 1.6 +/- 0.2 ph/s/cm^2.

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


GRB_name: GRB160912A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19917
SUBJECT: GRB 160912A: Swift-XRT refined Analysis
DATE:    16/09/13 05:26:11 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

L.M. McCauley (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU),
B. Mingo (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U.
Leicester), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Melandri
(INAF-OAB) and J.K. Cannizzo report on behalf of the Swift-XRT team:

We have analysed 8.0 ks of XRT data for GRB 160912A (Cannizzo et al.
GCN Circ. 19912), from 119 s to 36.9 ks after the  BAT trigger. The
data comprise 776 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
Beardmore et al. (GCN Circ. 19915).

The late-time light curve (from T0+5.8 ks) can be modelled with a
power-law decay with a decay index of alpha=.

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.63 (+/-0.04). The
best-fitting absorption column is  2.80 (+/-0.20) x 10^21 cm^-2, in
excess of the Galactic value of 2.4 x 10^21 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.81 (+0.11, -0.10)
and a best-fitting absorption column of 3.0 (+/-0.5) x 10^21 cm^-2. The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 4.2 x 10^-11 (5.6 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      3.0 (+/-0.5) x 10^21 cm^-2
Galactic foreground: 2.4 x 10^21 cm^-2
Excess significance: 2.1 sigma
Photon index:      1.81 (+0.11, -0.10)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00711914.

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


GRB_name: GRB160912A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19918
SUBJECT: GRB 160912A Liverpool Telescope optical afterglow
DATE:    16/09/13 08:04:49 GMT
FROM:    Nial Tanvir at U.Leicester  <nrt3@star.le.ac.uk>

N. R. Tanvir (U. Leicester), A. J. Levan (U. Warwick),
report on behalf of a larger collaboration:

We observed the field of Swift GRB 160912A (Cannizzo et al.
GCN 19912) with the 2m Liverpool Telescope on La Palma
with the IO:O camera.

Images were obtained in the r and i filters at two epochs,
each exposure being 25 mins in total. Within the revised
X-ray error circle (Beardmore et al. GCN 19915) we find a
point source with the following provisional magnitudes 
and start times relative to the BAT trigger time:

epoch1 dt=17053s i=22.10+/-0.15
epoch1 dt=18664s r=22.77+/-0.20
epoch2 dt=29285s i=22.57+/-0.17
epoch2 dt=30897s r=23.11+/-0.21

Given the evidence for fading, we conclude this is likely
the optical afterglow of the GRB.

The J2000 position of the source is 20:05:59.68 +57:33:54.9
to an accuracy of about 0.5".


GRB_name: GRB160910A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19919
SUBJECT: GRB 160910A: Mondy optical observations
DATE:    16/09/13 10:30:41 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

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

We observed the field of the GRB 160910A (Veres  et al., GCN 19901; Racusin 
et al., GCN 19902) with  AZT-33IK telescope of Sayan observatory (Mondy) 
starting on Sep., 12 (UT) 14:02:46. We obtained several images in R-filter. 
We  clearly detected optical afterglow (Ugarte Postigo et al., GCN 19907; 
Malesani et al., GCN  19908; Lipunov et al., GCN  19914). Preliminary 
photometry  of the afterglow is following

Date        UT start   t-T0      Filter Exp.   OT        UpLim (3 sigma)
                        (mid, days)       (s)

2016-09-12  14:02:46   1.87506    R      32*60 19.92+/-0.05  22.2


Photometry is based on nearby SDSS-DR9 stars
SDSS-DR9_id    R(Lupton transformation)
J144549.10+390403.4    16.86
J144552.78+390234.9    17.32
J144538.58+390535.0    18.34
J144541.35+390128.0    17.15 


GRB_name: GRB160912A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19920
SUBJECT: GRB 160912A: Mondy optical observations
DATE:    16/09/13 13:19:46 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

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

We observed the field of the GRB 160912A (Cannizzo et al.
GCN 19912) with  AZT-33IK telescope of Sayan observatory (Mondy) 
starting on Sep., 12 (UT) 18:14:25. We obtained several images in 
R-filter. We  clearly detected optical afterglow (Tanvir et al., GCN 
1991). Coordinates of the afterglow are (J2000)   20 05 59.64
+57 33 55.2 with uncertainty of 0.4 arcsec in both coordinates. The 
afterglow is 5 arcsec from nearby star (USNO-B1.0 1475-0371357 (J2000) 
RA = 20:06:00.32 Dec = +57:33:57.0 R2 = 18.21) and within enhanced XRT 
position (Beardmore et al. GCN 19915). Preliminary photometry  of the 
afterglow is following

Date        UT start   t-T0      Filter Exp.   OT        UL (3 sigma)
                        (mid, days)       (s)

2016-09-12  18:14:25   0.10883    R     30*120 22.57 +/-0.08  23.5

Photometry is based on nearby USNO-B1.0 stars
ID             RA           Dec        R2
2 1475-0371275 20:05:49.83 +57:33:12.9 17.09
3 1475-0371352 20:05:59.47 +57:32:43.8 17.46
4 1475-0371174 20:05:41.08 +57:33:00.0 17.43
5 1475-0371504 20:06:16.57 +57:32:46.8 17.62

The finding chart can be found at 
http://grb.rssi.ru/GRB160912A/GRB160912A_160912_AZT33IK_fc.png


GRB_name: GRB160912A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19921
SUBJECT: GRB 160912A: Swift/UVOT Weak Afterglow Detection
DATE:    16/09/13 16:10:01 GMT
FROM:    Frank Marshall at GSFC  <femarsha@khamseen.gsfc.nasa.gov>

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

The Swift/UVOT began settled observations of the field of GRB 160912A
138 s after the BAT trigger (Cannizzo et al., GCN Circ. 19912).
There is a weak detection of a source consistent with the XRT position
(Beardmore et al., GCN Circ. 19915) and the optical afterglow
positions (Tanvir and Levan, GCN Circ. 19918; Mazaeva et al., GCN Circ. 19919)
in the initial UVOT exposures. There is little evidence for
variability.

The preliminary UVOT position is:
   RA  (J2000) =  20:05:59.74  = 301.49893 (deg.)
   Dec (J2000) =  +57:33:56.0  =  57.56555 (deg.)
with an estimated uncertainty of 1.0 arcsec. (radius, 90% confidence).

Preliminary detections and 2-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              138         8135          883         22.03 +/- 0.27
v                  626         7110          411         20.60 +/- 0.44
b                  552         7931          584        >22.14
u                  296         7726          814        >21.92
w1                 675         7520          588        >21.25
m2                 650         7314          391        >20.75
w2                 602         8215          484        >21.05

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: GRB160912A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19922
SUBJECT: GRB 160912A: RATIR Optical and NIR Observations
DATE:    16/09/13 16:50:04 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), Ori Fox (STScI), J. Xavier
Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), 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), Harvey Moseley (GSFC), John
Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:

We observed the field of GRB 160912A (Cannizzo et al., GCN 19912) 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 2016/09 13.14 to 2016/09 13.24 UTC (11.20 to
13.52 hours after the BAT trigger), obtaining a total of 1.76 hours
exposure in the r and i bands and 0.74 hours exposure in the Z, Y, J, and H
bands.

We detect the optical afterglow reported by Tanvir et al. (GCN 19918).  In
comparison with the USNO-B1 and 2MASS catalogs, we obtain the following
detections and (3-sigma) upper limits:

r = 23.05 +/- 0.10
i = 22.73 +/- 0.13
Z = 22.62 +/- 0.31
Y = 22.13 +/- 0.29
J > 21.91
H > 21.72

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: GRB160910A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19923
SUBJECT: GRB 160910A: Swift/UVOT Detection
DATE:    16/09/14 17:12:41 GMT
FROM:    Lea Hagen at PSU  <lea.zernow.hagen@gmail.com>

L. M. Z. Hagen (PSU) and J. R. Cummings (GSFC/UMBC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 160910A
196954 s after the Fermi/GBM (Veres et al., GCN Circ. 19901) and
Fermi/LAT (Racusin et al., GCN Circ. 19902) triggers.  We detect a
fading source consistent with the XRT position (D'Ai et al., GCN Circ.
19904) and optical detections (de Ugarte Postigo et al., GCN Circ.
19907; Malesani et al., GCN Circ. 19908; Lipunov et al., GCN Circ.
19914; Mazaeva et al., GCN Circ. 19919).

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           196954       267060         1620          20.61+-0.14
white           267064       318724         2326          20.95+-0.14

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: GRB160912A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19924
SUBJECT: GRB 160912A, Swift-BAT refined analysis
DATE:    16/09/15 17:03:17 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC),
J. K. Cannizzo (NASA/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-239 to T+959 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 160912A (trigger #711914)
(Cannizzo, et al., GCN Circ. 19912).  The BAT ground-calculated position is
RA, Dec = 301.595, 57.585 deg which is
  RA(J2000)  =  20h 06m 22.7s
  Dec(J2000) = +57d 35' 04.8"
with an uncertainty of 2.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 96%.

The mask-weighted light curve shows some weak emissions that starts at ~ T-33 s,
and a FRED-like pulse from ~T+140 s to ~T+200 s. We do not have much
information of the burst emission afterwards due to some large gaps in the data
after ~T+320 s.

The time-averaged spectrum using the available data from T-33 to T+211 sec is best fit
by a simple power-law model.  The power law index of the time-averaged spectrum is
1.43 +- 0.11.  The fluence in the 15-150 keV band is 3.7 +- 0.3 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+148.56 sec in the 15-150 keV band
is 1.6 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/711914/BA/


GRB_name: GRB160910A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19925
SUBJECT: GRB 160910A: Maidanak optical observations
DATE:    16/09/16 12:20:32 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI), A. Pozanenko (IKI), B. Hafizov (UBAI). A. Volnova 
(IKI), O. Burhonov (UBAI) report on behalf of larger GRB follow-up 
collaboration:

We observed the  GRB 160910A (Veres  et al., GCN 19901; Racusin et al., 
GCN 19902) with AZT-22 telescope of Maidanak observatory equipped with 
SNUCAM in R filter. We  clearly detected optical afterglow (de Ugarte 
Postigo et al., GCN 19907; Malesani et al., GCN  19908; Lipunov et al., 
GCN  19914; Mazaeva et al., GCN  19919; Hagen et al., GCN 19923). 
Preliminary photometry  of the afterglow is following


Preliminary photometry of the afterglow  is following

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

2016-09-14   14:40:40  3.89933  R        15*120   21.40  0.14   22.2


Photometry is based on nearby SDSS-DR9 stars
SDSS-DR9_id    R(Lupton transformation)
J144549.10+390403.4    16.86
J144552.78+390234.9    17.32
J144538.58+390535.0    18.34
J144541.35+390128.0    17.15


GRB_name: GRB160917A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19926
SUBJECT: GRB 160917A: Swift detection of a burst
DATE:    16/09/17 11:46:10 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

J. L. Racusin (NASA/GSFC), S. D. Barthelmy (GSFC),
J. R. Cummings (NASA/UMBC), J. A. Kennea (PSU),
D. Malesani (DARK/NBI and DTU Space), F. E. Marshall (NASA/GSFC),
B. Mingo (U Leicester), K. L. Page (U Leicester) and
D. M. Palmer (LANL) report on behalf of the Swift Team:

At 11:30:19 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160917A (trigger=712505).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 295.671, +46.399 which is 
   RA(J2000)  =  19h 42m 41s
   Dec(J2000) = +46d 23' 56"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows several overlapping peaks
with a total duration of about 25 sec.  The peak count rate
was ~2300 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 11:31:52.9 UT, 93.6 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 295.66805, 46.40321 which
is equivalent to:
   RA(J2000)  = 19h 42m 40.33s
   Dec(J2000) = +46d 24' 11.6"
with an uncertainty of 4.2 arcseconds (radius, 90% containment). This
location is 16 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. No
spectrum from the promptly downlinked event data is yet available to
determine the column density. 

The initial flux in the 2.5 s image was 7.72e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 125 seconds with the White
filter  starting 99 seconds after the BAT trigger. No credible
afterglow candidate has  been found in the initial data products. The
2.7'x2.7' sub-image covers 100% of  the XRT error circle. The typical
3-sigma upper limit has been about 19.6 mag.  Results from the list of
sources  generated on-board are not available at this time. No
correction has been made  for the expected extinction corresponding to
E(B-V) of 0.16. 

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: GRB160917A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19927
SUBJECT: GRB 160917A: Enhanced Swift-XRT position
DATE:    16/09/17 14:58:00 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 77 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 160917A, 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 = 295.66637, +46.40368 which is equivalent
to:

RA (J2000): 19h 42m 39.93s
Dec (J2000): +46d 24' 13.2"

with an uncertainty of 2.5 arcsec (radius, 90% confidence).

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

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


GRB_name: GRB160917A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19928
SUBJECT: GRB 160917A: OSN I-band upper limits
DATE:    16/09/17 20:49:18 GMT
FROM:    Zach Cano at U of Iceland  <zewcano@gmail.com>

A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), Z. Cano (IAA-CSIC) & F. Aceituno
(IAA-CSIC) report on behalf of a larger collaboration:

We observed the field of GRB 160917A (Racusin et al.; GCN Circ. 19926) with
the 1.5-m OSN telescope in Granada, Spain.  We began observing at 19:08:34
UT (7.64 hours after the GRB onset), and obtained 14x300s images in
I-band.  In our coadded image, we find no new source in the refined XRT
error circle (Evans et al; GCN Circ. 19927) down to a a 3-sigma limit of
I(Vega) = 22.6.  The calibration was performed using a nearby star in the
USNO B1 catalog, and the upper limit corresponds to an isolated point
source in our co-added image.


GRB_name: GRB160917A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19929
SUBJECT: GRB 160917A: Mondy optical observations
DATE:    16/09/17 21:11:04 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

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

We observed the field of the GRB 160917A (Racusin et al. GCN 19926) with 
  AZT-33IK telescope of Sayan observatory (Mondy) starting on Sep., 17 
(UT) 14:30:30. We obtained several images in R-filter. We detected the 
optical source within enhanced XRT error circle (Evans et al., GCN 
19927) in coordinates (J2000) 19 42 39.81 +46 24 12.1 with 
uncertainities of 0.4 arcsec in both coordinates. Preliminary photometry 
  of the afterglow is following

Date        UT start   t-T0      Filter Exp.   OT        UL (3 sigma)
                        (mid, days)       (s)

2016-09-17  14:30:30   0.14601    R     120*30 20.60 +/- 0.20  22.9

Photometry is based on nearby USNO-B1.0 stars
ID             RA           Dec        R2

1 1363-0324591 19:42:38.95 +46:23:53.8 16.62
2 1364-0326339 19:42:40.68 +46:24:37.0 17.40
3 1363-0324630 19:42:42.78 +46:23:28.7 17.05

We suggest the source as optical afterglow of GRB 160917A.

The finding chart can be found at 
http://grb.rssi.ru/GRB160917A/160917A_Mondy_fc.png


GRB_name: GRB160917A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19930
SUBJECT: GRB 160917A: Swift-XRT refined Analysis
DATE:    16/09/17 22:43:12 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

S.L. Gibson (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), D.N. Burrows (PSU), T.G.R. Roegiers (PSU), L.M. McCauley
(PSU) and J.L. Racusin report on behalf of the Swift-XRT team:

We have analysed 6.2 ks of XRT data for GRB 160917A (Racusin et al. GCN
Circ. 19926), from 80 s to 17.4 ks after the  BAT trigger. The data
comprise 43 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. 19927).

The light curve can be modelled with a power-law decay with a decay
index of alpha=1.243 (+0.030, -0.029).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.81 (+0.22, -0.21). The
best-fitting absorption column is  2.8 (+1.1, -0.9) x 10^21 cm^-2, in
excess of the Galactic value of 1.7 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 4.1 x 10^-11 (5.5 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      2.8 (+1.1, -0.9) x 10^21 cm^-2
Galactic foreground: 1.7 x 10^21 cm^-2
Excess significance: 2.0 sigma
Photon index:      1.81 (+0.22, -0.21)

If the light curve continues to decay with a power-law decay index of
1.243, the count rate at T+24 hours will be 2.8 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x
10^-13 (1.5 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/00712505.

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


GRB_name: GRB160917A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19931
SUBJECT: GRB 160917A: Swift/UVOT Detection
DATE:    16/09/17 23:54:38 GMT
FROM:    Paul Kuin at MSSL  <npkuin@gmail.com>

N. P. M. Kuin (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 160917A
100 s after the BAT trigger (Racusin et al., GCN Circ. 19926). The
refined XRT position (Evans et al. GCN Circ. 19927) is close to a
bright star. However, a faint GRB candidate has been found at an
offset of 6.5 arcsec to the south east from the bright star in the
u exposures.
The UVOT candidate position is: RA, Dec = 295.66687, 46.40368 (J2000)
which is :
RA = 19:42:40.049
Dec = +46:24:13.25
with an estimated accuracy of 1.5 arcsec.

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              100          224          123          >21.01
b                 4222         4422          100          >20.64
u                 4017         5545          146           20.47 +- 0.36
v                 3402         5038          200          >19.77
uvw1              3812         5448          200          >20.16
uvm2              3606         5242          100          >19.97
uvw2              4633         4833          200          >19.70

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.16 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB160917A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19932
SUBJECT: GRB 160917A: Fermi GBM observation
DATE:    16/09/18 00:33:54 GMT
FROM:    Peter Veres at UAH  <veresp@gmail.com>

P Veres (UAH), A von Kienlin (MPE) and C Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 11:30:19.286 UT on 17 September 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160917A (trigger 495804623 / 160917479).
which was also detected by the Swift/BAT
â€‹ â€‹
(Racusin et al., GCN 19926).
â€‹ â€‹
The GBM on-ground location is consistent with the Swift position.


The angle from the Fermi LAT boresight at the GBM trigger time is 46
degrees.


The GBM light curve consists of a single peak
with a duration (T90) of about 47 s (50-300 keV).
The time-averaged spectrum from T0 to T0+14.1 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.00 +/- 0.05 and
the cutoff energy, parameterized as Epeak, is 1604 +/- 357 keV.


The event fluence (10-1000 keV) in this time interval is
(7.2 +/- 0.3)E-6 erg/cm^2. The 1-sec peak photon flux measured
starting from T0 in the 10-1000 keV band
is 5.1 +/- 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: GRB160917A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19933
SUBJECT: GRB 160917A: RATIR Optical and NIR Observations
DATE:    16/09/18 16:31:29 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), Ori Fox (STScI), J. Xavier
Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), 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), Harvey Moseley (GSFC), John
Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:

We observed the field of GRB 160917A (Racusin, et al., GCN 19926) 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 2016/09 18.12 to 2016/09 18.36 UTC (15.39 to
21.08 hours after the BAT trigger), obtaining a total of 3.72 hours
exposure in the r and i bands and 1.63 hours exposure in the Z, Y, J, and H
bands.

For a source within the Swift-XRT error circle (Evans et al., GCN 19927),
in comparison with the USNO-B1 and 2MASS catalogs, we obtain the following
upper limits (3-sigma):

  r > 24.31
  i > 24.28
  Z > 23.20
  Y > 22.90
  J > 22.57
  H > 22.20

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: GRB160917A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19934
SUBJECT: GRB 160917A: Swift-BAT refined analysis
DATE:    16/09/18 17:51:36 GMT
FROM:    Jay R. Cummings at Swift  <jcummings@cpi.com>

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-60 to T+243 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 160917A (trigger #712505)
(Racusin, et al., GCN Circ. 19926).  The BAT ground-calculated position is
RA, Dec = 295.652, 46.400 deg which is
   RA(J2000)  =  19h 42m 36.4s
   Dec(J2000) = +46d 23' 59.3"
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 43%.

The mask-weighted light curve shows an initial bright peak about 1 second
long with
some structure on finer time scales, and variable emission for another 30
seconds. Another weak peak occurs from T+50 to T+90 seconds. T90 (15-350
keV) is 16 +- 2 sec
(estimated error including systematics).

The time-averaged spectrum from T-0.34 to T+15.31 sec is best fit by a
simple
power-law model.  The power law index of the time-averaged spectrum is
0.89 +- 0.15.  The fluence in the 15-150 keV band is 1.3 +- 0.1 x 10^-06
erg/cm2.
The 1-sec peak photon flux measured from T-0.01 sec in the 15-150 keV band
is 2.2 +- 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/712505/BA/


GRB_name: GRB160910A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19935
SUBJECT: GRB 160910A: TSHAO optical observations
DATE:    16/09/18 20:03:32 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI), A. Kusakin (Fesenkov Astrophysical Institute), 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 GRB 160910A (Veres et al., GCN 19901; 
Racusin et al., GCN 19902) with Zeiss-1000 (East) 1-m telescope of Tien 
Shan Astronomical Observatory.  We obtained several images in R filter 
starting on Sep., 12 and Sep., 15. We clearly detected optical afterglow 
(Ugarte Postigo et al., GCN 19907; Malesani et al., GCN 19908; Lipunov 
et al., GCN 19914). Preliminary photometry of the afterglow is following

Date UT start t-T0 Filter Exp. OT UpLim (3 sigma)
                          (mid, days) (s)
2016-09-12 14:43:02 1.92176 R 27*120 19.96 +/- 0.08 21.7
2016-09-15 14:31:13 4.91356 R 27*120 21.70 +/- 0.30 21.7

Photometry is based on nearby SDSS-DR9 stars used in GCN 19919 (Mazaeva 
et al.).


GRB_name: GRB160917A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19936
SUBJECT: GRB 160917A: Mondy afterglow confirmation
DATE:    16/09/19 20:12:31 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

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

We observed the field of the GRB 160917A (Racusin et al. GCN 19926) with 
  AZT-33IK telescope of Sayan observatory (Mondy) starting on Sep., 18 
(UT) 15:25:21. We obtained several images in R-filter. We do not detect 
the optical source reported as afterglow candidate (Volnova et al. GCN 
19929; Kuin  et al. GCN  19931). Preliminary photometry of the field is 
following

Date        UT start   t-T0      Filter Exp.   OT     UL (3 sigma)
                        (mid, days)       (s)

2016-09-18  15:25:21   1.18522    R     60*60  n/d    22.0

Photometry is based on nearby USNO-B1.0 stars used in GCN circ. 19929.
In comparison with our previous observation (Volnova et al. GCN 19929) 
the source is not visible  up to 22.0 mag. The source faded between two 
epochs on at least  1.4 magnitudes and it is most probably the afterglow 
of GRB 160917A. Our observation is compatible with more deep RATIR 
observation in r-filter (Butler et al. GCN 19933).


GRB_name: GRB160910A
Detection_method: Fermi LAT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19937
SUBJECT: GRB 160910A: 15 GHz detection from AMI
DATE:    16/09/21 22:42:24 GMT
FROM:    Kunal Mooley at Oxford U  <kunal.mooley@physics.ox.ac.uk>

K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson 
(Curtin), T. Cantwell (Manchester), D. Titterington, S. H. Carey, J. 
Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), K. 
Grainge, A. Scaife (Manchester)

We observed the Fermi/LAT GRB 160910A (Racusin et al., GCN 19902) with 
the AMI Large Array at 15 GHz on 2016 Sep 12.65, Sep 13.68, Sep 15.67, 
and Sep 20.68 (UT) as part of the 4pisky program. We detect the radio 
afterglow at the NOT location (Malesani et al., GCN 19908) at flux 
densities of 791+/-55 uJy, 1151+/-82 uJy, 840+/-146 uJy, and 462+/-39 
uJy respectively.

We thank the AMI staff for scheduling these observations. The AMI-GRB 
database is a log of all GRB follow up observations with the AMI, and is 
available at http://4pisky.org/ami-grb/.


GRB_name: GRB160925A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19938
SUBJECT: GRB 160925A / Fermi 496473540: Global MASTER Net OT discovery
DATE:    16/09/26 07:51:33 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

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

D.Buckley, S. Potter,
South African Astronomical Observatory

H. Levato, C. Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

R.Podesta, C.Lopez, F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA)


R. Rebolo, M. Serra Ricart, N. Lodieu, G. Israelian
The Instituto de Astrofisica de Canarias

K.Ivanov, J.Rabinovich, N.M.Budnev, 
Irkutsk State University

A. Tlatov, V.Senik, D. Dormidontov, A.Parkhomenko
Kislovodsk Solar Station of the Pulkovo Observatory

V.Yurkov, Yu.Sergienko, A.Gabovich
Blagoveschensk Educational State University, Blagoveschensk



MASTER-SAAO  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
pointed to the FERMI GBM trigger 496473540 (GRB160925A ) at 2016-09-25
2016-09-25 18:00:46 UT and automatically started inspection (there was a 
day at the trigger time 05:18:56.45UT).

MASTER-SAAO auto-detection system discovered OT source at
(RA, Dec) = 22h 28m 17.90s -14d 56m 57.4s
on 2016-09-25.75053 UT with  unfiltered magnitude m_OT=15.9m (mlim=19.7m), 
Bmag=15.3, Imag=15.9 (Gress et al. ATEL #9548).

There is no any known sources inside 5" in VIZIER database, it gives 
amplitude of current outburst more then 6mag.

The discovery and reference images are available at 
http://master.sai.msu.ru/static/OT/222817.90-145657.4.png

Spectral observations are required.

The message may be cited.


GRB_name: GRB160925A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19939
SUBJECT: GRB160925A / Fermi 496473540: MASTER optical transient confirmation by LCOGT-FTN
DATE:    16/09/26 10:26:53 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi (U. Ferrara), S. Kobayashi, I.A. Steele (LJMU), C.G. Mundell 
(U. Bath), A. Gomboc (U. Nova Gorica) on behalf of a large collaboration 
report:

The 2-m LCOGT Faulkes Telescope North began observing the MASTER optical 
transient possibly associated to GRB160925A/Fermi 496473540 (Lipunov et 
al., GCN 19938) on September 26, 08:11 UT (0.6 days since MASTER 
observations). We confirm the presence of an uncatalogued object at the 
following position:

RA(J2000)=  22:28:17.82
Dec(J2000)= -14:56:56.6

with an uncertainty of 1.0 arcsec and R=16.17 +- 0.01 mag, I=16.00+-0.01 
mag, as calibrated against USNOB-1 star 22:28:23.443, -14:57:33.95 using 
R2=13.69 mag, I=13.00 mag.
Given its ecliptic coordinates (333 deg, -5 deg), with reference to the 
IAU Minor Planet Center we checked that there is no known minor planet 
or comet brighter than V=20.0 mag within 10 arcminutes at the epoch of 
our observations.


GRB_name: GRB160925A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19940
SUBJECT: GRB 160925A: Swift ToO observations
DATE:    16/09/26 15:36:15 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/GBM/MASTER GRB 160925A. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020701

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/GBM/MASTER 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: GRB160925A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19941
SUBJECT: GRB 160925A / Fermi 496473540: MASTER OT observations
DATE:    16/09/26 16:34:17 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov,
Lomonosov Moscow State University, Sternberg Astronomical Institute


We continued observation of MASTER OT J222817.90-145657.4 , detected by 
MASTER inside FERMI GBM trigger 496473540 (Lipunov et al., GCN 19938)
error box. The OT light curve from MASTER-SAAO  is 
available at

http://observ.pereplet.ru/images/MASTEROTJ222817.90-145657.4.jpg

and looks like dwarf novae outburst (amplitude more then 6.1m).


The message may be cited.


GRB_name: GRB160917A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19942
SUBJECT: GRB160917A: AstroSat CZTI detection
DATE:    16/09/27 03:14:26 GMT
FROM:    Varun Bhalerao at IUCAA  <varunb@iucaa.in>

V. Bhalerao (IUCAA), V. Kumar (IUCAA), D. Bhattacharya (IUCAA), A. R. Rao (TIFR), S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:

Analysis of Astrosat data showed the CZTI detection of GRB160917A (Swift BAT detection: S.Barthelmy et al., GCN Circ. 19926).

The source was clearly detected in the 40-200 keV energy range. The light curve shows a single peak at 11:30:25.0 UT, 6 seconds after Swift Trigger at 11:30:19.0 UT. The peak count rate was 116.0 counts/sec above the background (four quadrants summed together), with a total of 1008.0 counts. The local mean background count rate was 327.0 counts/sec. Using cumulative rates, we measure a T90 of 21 sec.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb . CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB160824B
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19943
SUBJECT: GRB160824B: AstroSat CZTI detection
DATE:    16/09/27 03:15:19 GMT
FROM:    Varun Bhalerao at IUCAA  <varunb@iucaa.in>

V. Bhalerao (IUCAA), V. Kumar (IUCAA), D. Bhattacharya (IUCAA), A. R. Rao (TIFR), S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:

Analysis of Astrosat data showed the CZTI detection of GRB160824B (Fermi-GBM detection: R. Hamburg et al., GCN Circ. 19856).

The source was clearly detected in the 40-200 keV energy range. The light curve shows a single peak at 14:21:13.5 UT, 1.5 seconds after Fermi Trigger at 14:21:12 UT. The peak count rate was 388.49 counts/sec above the background (four quadrants summed together), with a total of 992 counts. The local mean background count rate was 120.0 counts/sec. Using cumulative rates, we measure a T90 of 2.9 secs.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb . CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB160925A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19944
SUBJECT: GRB 160925A: Optical spectroscopy of MASTER optical transient
DATE:    16/09/27 08:53:03 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

I.A.Steele (LJMU), C. Guidorzi (U. Ferrara), C. G. Mundell (Bath), A. Gomboc (U. Nova Gorica), J. Japelj (INAF-OAT) report on behalf of a larger collaboration.

We report optical spectroscopy of the MASTER optical transient (GCN 19938, 19939, 19941) which is a possible optical counterpart to the FERMI GBM trigger 496473540 (GRB160925A).

The optical transient has the ID MASTER OT J222817.90-145657.4.

A low resolution (R~350) optical (400-800nm) spectrum was obtained using the SPRAT spectrograph of the Liverpool Telescope (La Palma) on 26-09-16 at  21:25:49 UT. The 300 second exposure shows a strong, blue continuum with clear H-beta and H-gamma absorption lines at zero redshift. H-alpha is not  present either in emission or absorption (implying a degree of H-alpha emission).  The spectrum is consistent with a dwarf nova during outburst and therefore not likely to be associated with the Fermi trigger.


GRB_name: GRB160925A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19945
SUBJECT: GRB 160925A: Bassano Bresciano Photometry of MASTER optical transient
DATE:    16/09/27 09:44:27 GMT
FROM:    Ulisse Quadri at Bassano Bresciano Obs  <oabb@ulisse.bs.it>

U.Quadri, L.Strabla and R.Girelli report:

The photometrical observations of the MASTER optical transient (GCN 19938, 19939, 19941) 
Is it a possible optical counterpart to the FERMI GBM trigger 496473540 (GRB160925A).

The optical transient has the ID MASTER OT J222817.90-145657.4.

Observations made by the 250 mm F/4.8 Newton robotic telescope of 
(IAU station 565) Bassano Bresciano Observatory.

Observations started on 2016-09-26 at 20h 04m UT and ended 2016-09-26 at 22h 32m UT
Exposures time of 60 sec each.

Reference star is: UCAC4 376-178184
Chk Star is: UCAC4 375-181914

------------------------------------
                       CV Mag.    
     T (JD)"         OT      Chk1 
------------------------------------
2457658.33643518   16.089   13.981
2457658.33721064   15.947   13.953
2457658.33797453   16.051   13.976
2457658.33875000   16.019   13.962
2457658.33952546   16.026   13.991
2457658.34030092   15.986   13.963
2457658.34107638   16.060   13.968
2457658.34185185   16.065   13.969
2457658.34262731   16.132   13.977
2457658.34339120   16.060   13.991
2457658.34439814   16.072   13.973
2457658.34516203   15.988   13.983
2457658.34592592   16.043   13.959
2457658.34668981   16.069   13.981
2457658.34745370   15.963   14.002
2457658.34840277   16.083   13.969
2457658.34916666   16.035   13.958
2457658.34991898   16.068   13.963
2457658.35069444   16.054   13.989
2457658.35144675   15.944   13.975
2457658.35239583   15.962   13.986
2457658.35315972   16.040   14.013
2457658.35392361   16.072   13.995
2457658.35468749   15.956   13.976
2457658.35543981   15.983   13.990
2457658.35638888   15.992   13.980
2457658.35715277   16.010   13.969
2457658.35791666   15.996   13.990
2457658.35868055   15.974   13.971
2457658.35944444   15.992   13.989
2457658.36039351   16.111   13.952
2457658.36114583   16.004   14.008
2457658.36190972   15.980   13.991
2457658.36267361   15.939   13.978
2457658.36343749   16.035   14.001
2457658.36438657   15.972   13.985
2457658.36515046   16.028   13.989
2457658.36591435   16.055   13.989
2457658.36667824   16.063   13.989
2457658.36743055   16.015   13.987
2457658.36837962   16.036   13.976
2457658.36914351   15.971   13.997
2457658.36990740   15.935   13.997
2457658.37067129   16.016   13.963
2457658.37143518   16.077   14.017
2457658.37238425   15.977   13.968
2457658.37314814   15.985   13.995
2457658.37391203   15.905   13.959
2457658.37466435   15.941   13.974
2457658.37542824   15.998   13.982
2457658.37637731   16.002   13.971
2457658.37714120   15.934   13.970
2457658.37790509   15.859   13.949
2457658.37866898   15.994   13.950
2457658.37942129   16.021   13.966
2457658.38037037   16.015   13.978
2457658.38113425   16.142   13.966
2457658.38189814   15.944   14.019
2457658.38266203   16.022   13.975
2457658.38342592   16.174   13.992
2457658.38436342   16.119   14.019
2457658.38512731   16.109   13.959
2457658.38589120   16.112   13.966
2457658.38665509   15.908   13.963
2457658.38740740   16.054   13.975
2457658.38835648   16.030   13.987
2457658.38912037   16.184   13.968
2457658.39633101   16.020   14.001
2457658.39709490   15.941   13.967
2457658.39785879   16.160   13.989
2457658.39863425   15.937   13.958
2457658.39938657   16.069   13.992
2457658.40033564   16.051   13.993
2457658.40262731   16.062   13.963
2457658.40908564   15.910   14.006
2457658.40984953   16.049   13.979
2457658.41061342   16.024   13.953
2457658.41231481   16.074   13.989
2457658.41307870   16.090   13.996
2457658.41384259   15.901   13.986
2457658.41460648   16.137   13.986
2457658.41537037   16.033   13.994
2457658.41631944   16.053   13.972
2457658.41708333   16.132   13.979
2457658.41783564   16.025   13.963
2457658.41859953   16.029   13.968
2457658.41936342   16.067   13.987
2457658.42031250   16.031   13.965
2457658.42107638   16.007   13.978
2457658.42184027   16.031   13.950
2457658.42260416   15.986   13.958
2457658.42335648   16.055   13.939
2457658.42430555   16.011   13.949
2457658.42506944   15.992   13.983
2457658.42583333   15.966   13.978
2457658.42736111   16.004   13.967
2457658.42829861   16.053   13.975
2457658.42906250   16.132   13.953
2457658.42982638   15.971   13.933
2457658.43059027   16.006   13.955
2457658.43135416   16.138   13.985
2457658.43229166   15.972   13.962
2457658.43305555   15.962   13.966
2457658.43381944   16.082   13.962
2457658.43458333   15.992   13.944
2457658.43534722   15.873   13.947
2457658.43628472   15.986   13.972
2457658.43781250   16.153   13.968
2457658.43857638   16.018   13.957

Magnitudes were estimated with the UCAC4 cat. and 
are not corrected for galactic dust extinction.   

Reference: http://www.osservatoriobassano.org/GRB.asp

The message may be cited.


GRB_name: GRB160925A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19946
SUBJECT: GRB 160925A: MITSuME Akeno Optical Observations
DATE:    16/09/27 10:33:25 GMT
FROM:    Taketoshi Yoshii at Tokyo Tech  <yoshii.t.ac@m.titech.ac.jp>

T.Fujiwara, T. Yoshii, Y.Saito, R.Itoh, Y. Tachibana,
Y.Ono, S.Harita, T.Ozawa, K.Saisho, Y. Yatsu, and N. Kawai (Tokyo Tech)

report on behalf of the MITSuME collaboration:

We observed the field of GRB 160925A (C. Guidorzi et al., GCN
Circular #19939) 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 2016-09-26 12:21:13 UT (~0.75 day after the burst) and
we detected the optical counterpart in Rc and Ic band.
The measured magnitudes were listed as follows.

We obtained following results for the magnitudes.

T0+[day]    MID-UT      T-EXP[sec]         g'              Rc                      Ic
-------------------------------------------------------------------------------------------------------
 0.75           12:53:24          480         15.96 +/- 0.04      16.00 +/- 0.05      15.93 +/- 0.06
-------------------------------------------------------------------------------------------------------

T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.


GRB_name: GRB160925A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19947
SUBJECT: GRB 160925A/MASTER optical transient: Mondy optical observations
DATE:    16/09/27 12:34:06 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

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

We observed the field of the Fermi GRB 160925A (trigger #496473540) with 
  AZT-33IK telescope of Sayan observatory (Mondy) starting on Sep., 26 
(UT) 14:38:09. We obtained several images in R-filter. We  clearly 
detected optical transient (Lipunov et al., GCN 19938; Guidorzi et al., 
GCN  19939). Preliminary photometry  of the transient is following

Date        UT start   t-T0      Filter Exp.   OT        UpLim (3 sigma)
                        (mid, days)       (s)
2016-09-26  14:38:09   0.88014    R      30*120 16.06+/-0.03  23.0


Photometry is based on nearby USNO-B1.0 stars

USNO-B1.0 R2
0750-0813972 16.86
0750-0813954 17.70
0750-0813947 17.78


GRB_name: GRB160925A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19948
SUBJECT: XRT refined analysis for GRB 160925A  
DATE:    16/09/27 15:01:49 GMT
FROM:    Boris Sbarufatti at INAF-OAB/IASFPA  <boris.sbarufatti@brera.inaf.it>

J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), V. Dâ€™Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), T.G.R. Roegiers (PSU), L.M. McCauley (PSU), J.A. Kennea (PSU), B. Mingo (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/GBM-detected burst GRB 160925A, pointing towards the direction of the MASTER variable optical source (Lipunov et al., GCN 19938), collecting 3.0 ks of Photon Counting (PC) mode data between T0+122.7 ks and T0+133.6 ks. 

No X-ray sources have been detected consistent with being within 9.9 arcsec of the MASTER position. The 3-sigma upper limit in the field is 0.003 ct  s^-1, corresponding to a 0.3-10 keV observed flux of 1.1e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum).

The lack of X-ray detection is consistent with the classification of the optical source as a dwarf nova (Steele et al., GCN 19944).

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/00020701.

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


GRB_name: GRB160910A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19949
SUBJECT: GRB160910A: AstroSat CZTI detection
DATE:    16/09/27 16:12:44 GMT
FROM:    Varun Bhalerao at IUCAA  <varunb@iucaa.in>

V. Bhalerao (IUCAA), V. Kumar (IUCAA), D. Bhattacharya (IUCAA), A. R. Rao (TIFR), S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:

Analysis of Astrosat data showed the CZTI detection of a very bright GRB160910A (Fermi-GBM detection: P. Veres et al., GCN Circ. 19901).

The source was clearly detected in the 40-200 keV energy range. The light curve shows a single peak at 17:19:47.15 UT, 8 seconds after Fermi Trigger at 17:19:39.15 UT and a peak count rate of 1738 counts/sec above the background (four quadrants summed together), with a total of 7184 counts. The local mean background count rate was 343 counts/sec. Using cumulative rates, we measure a T90 of 9.44 secs.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb . CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB160912A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19950
SUBJECT: GRB 160912A: 15 GHz upper limits from AMI
DATE:    16/09/27 16:29:37 GMT
FROM:    Kunal Mooley at Oxford U  <kunal.mooley@physics.ox.ac.uk>

K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson 
(Curtin), T. Cantwell (Manchester), D. Titterington, S. H. Carey, J. 
Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), K. 
Grainge, A. Scaife (Manchester)

The AMI Large Array robotically triggered on the Swift alert for GRB 
160912A (Cannizzo et al., GCN 19912) as part of the 4pisky program, and 
subsequent follow up observations were obtained up to 10 days 
post-burst. Our observations at 15 GHz on 2016 Sep 12.72, Sep 13.81, and 
Sep 18.87 (UT) do not reveal any radio source at the XRT location 
(Beardmore et al., GCN 19915), with 3sigma upper limits of 147 uJy, 258 
uJy, and 102 uJy respectively.

We thank the AMI staff for scheduling these observations. The AMI-GRB 
database is a log of all GRB follow up observations with the AMI, and is 
available at http://4pisky.org/ami-grb/.


GRB_name: GRB160917A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19951
SUBJECT: GRB 160917A: 15 GHz upper limits from AMI
DATE:    16/09/27 16:33:39 GMT
FROM:    Kunal Mooley at Oxford U  <kunal.mooley@physics.ox.ac.uk>

K. P. Mooley (Hintze Fellow, Oxford), T. D. Staley, R. P. Fender 
(Oxford), G. E. Anderson (Curtin), T. Cantwell (Manchester), D. 
Titterington, S. H. Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, 
P. Scott (Cambridge), K. Grainge, A. Scaife (Manchester)

The AMI Large Array robotically triggered on the Swift alert for GRB 
160917A (Racusin et al., GCN 19926) as part of the 4pisky program, and 
subsequent follow up observations were obtained up to 10 days 
post-burst. Our observations at 15 GHz on 2016 Sep 17.65, Sep 20.87, and 
Sep 24.87 (UT) do not reveal any radio source at the XRT location (Evans 
et al., GCN 19927), with 3sigma upper limits of 150 uJy, 84 uJy, and 90 
uJy respectively.

We thank the AMI staff for scheduling these observations. The AMI-GRB 
database is a log of all GRB follow up observations with the AMI, and is 
available at http://4pisky.org/ami-grb/.


GRB_name: GRB160927A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19952
SUBJECT: GRB 160927A: Swift detection of a short hard burst
DATE:    16/09/27 18:16:06 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

S. L. Gibson (U Leicester), N. Gehrels (NASA/GSFC),
J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU)
report on behalf of the Swift Team:

At 18:04:49 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160927A (trigger=713782).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 256.264, +17.311 which is 
   RA(J2000) = 17h 05m 03s
   Dec(J2000) = +17d 18' 38"
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 0.5 sec.  The peak count rate
was ~5000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 18:06:09.3 UT, 79.5 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 256.24288, 17.33165 which is equivalent
to:
   RA(J2000)  = 17h 04m 58.29s
   Dec(J2000) = +17d 19' 53.9"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 103 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 7.14
x 10^20 cm^-2 (Willingale et al. 2013). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 84 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 0.08. 

Burst Advocate for this burst is S. L. Gibson (slg44 AT 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: GRB160927A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19953
SUBJECT: GRB 160927A: Prompt enhanced Swift-XRT position
DATE:    16/09/27 18:33:51 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 160927A, we find an
enhanced XRT position of the afterglow: RA, Dec: 256.2427, 17.3316
which is equivalent to:
   RA (J2000)  = 17 04 58.24
   Dec (J2000) = +17 19 53.7
with an uncertainty of 2.1 arcseconds (radius, 90% confidence).
Analysis of the promptly available data is online at
http://www.swift.ac.uk/sper/713782.

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: GRB160927A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19954
SUBJECT: GRB 160927A: RTT150 optical afterglow candidate
DATE:    16/09/27 21:01:06 GMT
FROM:    Rodion Burenin at IKI, Moscow  <rodion@hea.iki.rssi.ru>

A. Tkachenko, R. Burenin, M. Pavlinsky, R. Sunyaev (IKI),
I. Bikmaev, E. Irtuganov, N. Sakhibullin (KFU/AST),
I. Khamitov, H. Kirbiyik (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.)

report:

We observed field of Swift short hard GRB 160927A (Gibson et al., GCN
19952) with Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe,
TUBITAK National Observatory, Turkey) using TFOSC. We obtained four
600s exposures in SDSS-r filter at high airmass and very poor seeing
(2.5 arcsec) starting at 18:59:24 UT, i.e. approximately 55 min after
the burst. 

At the edge of improved XRT localization (Evans et al., GCN 19953) we
find faint optical source, which is not present in SDSS image, at the
position: 

RA,Dec: 17:04:58.21 +17:19:55.5  (J2000)

For this source we estimate SDSS-r mag =~ 22.3. The finding chart can
be found at: 

http://dlc.rsdc.rssi.ru/~rodion/grb/160927a/r.jpg


GRB_name: GRB160927A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19955
SUBJECT: GRB160927A: D50 optical limit
DATE:    16/09/27 21:09:50 GMT
FROM:    Martin Jelinek at Astro.Inst-AVCR,Ondrejov  <martin.jelinek@asu.cas.cz>

Martin Jelinek, Jan Strobl, Rene Hudec, Vojtech Simon
and Cyril Polasek (ASU CAS Ondrejov, CZ) report:

The 50cm robotic telescope (D50) of Ondrejov
observatory in Czech republic reacted robotically to
the alert of GRB160927A (Gibson et al, GCNC 19952),
obtaining a series of 10s unfiltered images starting at
18:05:29.9UT, i.e. 40s post trigger.

We do not detect any new source within or near the XRT
error circle (Evans, GCNC 19953) in comparison to
USNO-B1.0 catalog neither in single images (3-sigma
limit R>18.7) nor in a combined 25x10s frame (mean exp
time 124s post trigger, 3-sigma limit R>20.5).


GRB_name: GRB160927A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19956
SUBJECT: GRB 160927A: TNG optical afterglow confirmation
DATE:    16/09/27 21:25:12 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>

P. D'Avanzo, A. Melandri (INAF-OAB), E. Palazzi (INAF-IASFBo), V. D'Elia (INAF/OAR & ASI/ASDC), 
L. Di Fabrizio, D. Carosati (INAF-TNG) report on behalf of the CIBO collaboration: 

We observed the field of the short GRB 160927A (Gibson et al., GCN 19952)
 with the 3.6m Telescopio Nazionale Galileo (TNG) equipped with DOLoRes. 
Observations were carried out in the r-sdss filter. Observations started on Sept 27 
at 20:12:49 UT (2.13 hours after the burst) and consist in a series of 5 images, 
each one lasting 180 seconds. 

At the enhanced XRT position (Evans, GCN 19953) in the co-added image we 
detect an object at the following coordinates (J2000):

RA, Dec = 17:04:58.22, +17:19:54.9

+/- 0.5". The object has a magnitude r = 22.6 +/- 0.1 (calibrated against nearby SDSS stars). 
This object is the same reported by Tkachenko et al. (GCN 19954). Given the mild evidence 
for fading, we propose this object as the optical afterglow of GRB 160927A. 


GRB_name: GRB160927A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19957
SUBJECT: GRB 160927A: Enhanced Swift-XRT position
DATE:    16/09/28 00:38:09 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 3482 s of XRT Photon Counting mode data and 5 UVOT
images for GRB 160927A, 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 = 256.24259, +17.33197 which is equivalent
to:

RA (J2000): 17h 04m 58.22s
Dec (J2000): +17d 19' 55.1"

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: GRB160927A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19958
SUBJECT: GRB 160927A: Swift-XRT refined Analysis
DATE:    16/09/28 00:52:17 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

K.L. Page (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri
(INAF-OAB), P. D'Avanzo (INAF-OAB), L.M. McCauley (PSU), J.A. Kennea
(PSU), B. Sbarufatti (INAF-OAB/PSU), B. Mingo (U. Leicester), A.P.
Beardmore (U. Leicester) and S.L. Gibson report on behalf of the
Swift-XRT team:

We have analysed 6.6 ks of XRT data for GRB 160927A (Gibson et al. GCN
Circ. 19952), from 89 s to 13.2 ks after the  BAT trigger. The data are
entirely in Photon Counting (PC) mode. The enhanced XRT position for
this burst was given by Goad et al. (GCN Circ. 19953).

The light curve can be modelled with a power-law decay with a decay
index of alpha=0.99 (+0.08, -0.07).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.72 (+0.29, -0.17). The
best-fitting absorption column is  7.6 (+9.0, -0.4) x 10^20 cm^-2,
consistent with the Galactic value of 7.1 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 3.9 x 10^-11 (4.3 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      7.6 (+9.0, -0.4) x 10^20 cm^-2
Galactic foreground: 7.1 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.72 (+0.29, -0.17)

If the light curve continues to decay with a power-law decay index of
0.99, the count rate at T+24 hours will be 9.0 x 10^-4 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.5 x
10^-14 (3.9 x 10^-14) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00713782.

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


GRB_name: GRB160927A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19959
SUBJECT: GRB 160927A: GROND Observations
DATE:    16/09/28 02:36:11 GMT
FROM:    Philip Wiseman at MPE/Swift  <wiseman@mpe.mpg.de>

P Wiseman (MPE Garching), J Bolmer (ESO Vitacura), and J Greiner (MPE
Garching) report on behalf of the GROND team:

We observed the field of GRB 160927A (Swift trigger 713782; Gibson et al.,
GCN #19952) 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 23:26 UT on 27/09/2016, 5h 21m after the GRB
trigger, and continued for ~1 hour, mostly during astronomical twilight.
They were performed at an average seeing of 1.8" and at an average airmass
of 2.

Based on 22.4 min of total exposures around a mid-time of 5.58 hours after
the trigger we marginally detect the source reported by Tkachenko et al.
(GCN #19954) and D'Avanzo et al. (GCN#19956) in the GROND r-band with an
AB magnitude of:

r' = 23.9 +/- 0.4 mag.

The apparent fading since the RTT150 and TNG observations is convincing
evidence for this source being the afterglow, and further suggests a
steepening of the afterglow light-curve since the TNG observation.

The given magnitude is calibrated against SDSS zeropoints and is not
corrected for the expected Galactic foreground extinction corresponding to
a reddening of E_(B-V)=0.07 mag in the direction of the burst (Schlafly &
Finkbeiner, 2011).


GRB_name: GRB160927A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19960
SUBJECT: GRB 160927A: NOT optical observations
DATE:    16/09/28 05:44:46 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

D. Xu (NAOC/CAS), D. Malesani (DARK/NBI and DTU Space), H. Dahle, B. 
Racine (Oslo U.), T. Pursimo (NOT), J. P. U. Fynbo (DARK/NBI), report on 
behalf of a larger collaboration:

We observed the field of GRB 160927A (Gibson et al., GCN 19952) using 
the 2.56-m Nordic Optical Telescope (NOT) equipped with the ALFOSC 
camera. Observations started at 21:24:39 UT on 2016-09-27 (i.e., 3.33 hr 
after the trigger) and 5x300s SDSS r-band frames were obtained.

The previously reported optical afterglow of the burst (Tkachenko et 
al., GCN 19954; D'Avanzo et al., GCN 19956; Wiseman et al., GCN 19959) 
is clearly detected in our stacked r-band image. It has m(r)=23.07 +/- 
0.10 at a median time of 3.56 hr post-burst, calibrated with nearby SDSS 
stars.

Combined with the RTT150, TNG, and GROND data points reported in the 
above GCN Circulars, we confirm the steepening of the afterglow 
light-curve (Wiseman et al., GCN 19959). A rough estimate gives rise to 
alpha_1~0.6, a break time of ~3.1 hr post-burst, and alpha_2~1.7 (but 
poorly constrained).


GRB_name: GRB160927A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19961
SUBJECT: GRB 160927A: Swift-BAT refined analysis
DATE:    16/09/28 07:13:26 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), S. L. Gibson (U Leicester), 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 160927A (trigger #713782)
(Gibson, et al., GCN Circ. 19952).  The BAT ground-calculated position is
RA, Dec = 256.268, 17.334 deg which is
    RA(J2000)  =  17h 05m 04.2s
    Dec(J2000) = +17d 20' 01.8"
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 50%.
  
The mask-weighted light curve in 16 msec binning shows at least two
peaks.  The first peak starts at T-0.2 sec, peaks at T+0.2 sec and
ends at T+0.3 sec.  The second peak starts at T+0.3 sec, peaks at
T+0.4 sec and ends at T+0.5 sec.  T90 (15-350 keV) is 0.48 +- 0.10 sec
(estimated error including systematics).

The time-averaged spectrum from T+0 to T+0.54 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.12 +- 0.26.  The fluence in the 15-150 keV band is 1.4 +- 0.2 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.23 sec in the 15-150 keV band
is 1.9 +- 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.
  
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/713782/BA/


GRB_name: GRB160927A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19962
SUBJECT: GRB 160927A: Bassano Bresciano Observatory optical upper limit
DATE:    16/09/28 11:26:02 GMT
FROM:    Ulisse Quadri at Bassano Bresciano Obs  <oabb@ulisse.bs.it>

U.Quadri, L.Strabla and R.Girelli report:

We imaged the field of GRB 160927A detected by SWIFT(trigger 713782)
with the robotic telescope of (IAU station 565) Bassano Bresciano 
Observatory, Italy. Member of: 
AAVSO - American Association of Variable Star Observers.
ISSP - Italian Supernovae Search Project.
UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili.

The observations started 11.72 min after the GRB trigger,  
with our Newton telescope D=250 mm F/D=4.8.

Weather conditions were good.

We co-added 52 exposures of 60 sec each.

Start T0+      End T0+      CV lim
11.72 min     65.71 min     19.5

We did not found any optical counterpart in the error box of the XRTcandidate.
S. L. Gibson (U Leicester), N. Gehrels (NASA/GSFC), et al.

Magnitudes were estimated with the UCAC4 cat. and 
are not corrected for galactic dust extinction.

Reference:
http://www.osservatoriobassano.org/GRB.asp

The message may be cited.


GRB_name: GRB160927A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19963
SUBJECT: GRB 160927A: Swift/UVOT Upper Limits
DATE:    16/09/28 16:13:58 GMT
FROM:    Paul Kuin at MSSL  <npkuin@gmail.com>

Paul Kuin(MSSL-UCL) and S. L. Gibson (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 160927A
85 s after the BAT trigger (Gibson et al., GCN Circ. 19952).
No optical afterglow consistent with the optical position
(D'Avanzo et al. GCN Circ. 19956)
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            85          235          147         >21.0
u_FC               297          547          246         >20.4
white               85        13184         1426         >21.8
v                  627         6999          510         >19.9
b                  553        12500         1179         >21.5
u                  297        11587         1433         >21.1
w1                 850         7411          491         >20.2
m2                 826         7204          294         >20.5
w2                 602         6794          510         >21.0

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.08 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB160927A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19964
SUBJECT: GRB 160927A: Magellan imaging
DATE:    16/09/28 18:36:06 GMT
FROM:    Wen-fai Fong at U of Arizona  <wfong@email.arizona.edu>

W. Fong (Univ. of Arizona), S. Sheppard (Carnegie DTM) and E. Berger
(Harvard) report:

We imaged the location of the short-duration GRB 160927A (Gibson et al.,
GCN 19952) with the Inamori-Magellan Areal Camera and Spectrograph (IMACS)
mounted on the Magellan/Baade 6.5-m telescope at a mid-time of 2016 Sep
28.00 UT (5.94 hr post-burst). We obtained 4x200-sec of r-band exposures in
0.75" seeing at an airmass of 1.9. We clearly detect the optical afterglow
(Tkachenko et al., GCN 19954; D'Avanzo et al., GCN 19956; Wiseman et al.,
GCN 19959; Xu et al., GCN 19960). Tied to 10 SDSS stars in the field, we
calculate a magnitude of r_AB=23.84 +/- 0.21, not corrected for Galactic
extinction in the direction of the burst.


GRB_name: GRB160910A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19966
SUBJECT: Possible radio detection of GRB 160910A with the GMRT
DATE:    16/09/29 08:34:23 GMT
FROM:    Nayana A J at NCRA-TIFR  <nayan89deva@gmail.com>

A.J Nayana  (NCRA-TIFR) and Poonam Chandra (NCRA-TIFR) report:

We carried out Giant Metrewave Radio Telescope (GMRT) observations of GRB 160910A
(Veres et al. 2016., GCN Circ. 19901. , Racusin et al. 2016., GCN Circ. 19902) at 1390
MHz band on 2016 Sep 27.21 UT. We detect a 4-sigma source within the XRT error circle
(D'Ai et al. 2016., GCN Circ. 19904) with a flux density of 185+/-69 uJy. This is likely
to be the radio afterglow of GRB 160910A. Map rms is 35 uJy.


We thank GMRT staff for making these observations possible.


GRB_name: GRB161001A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19967
SUBJECT: GRB 161001A: Swift detection of a burst
DATE:    16/10/01 01:15:39 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

K. L. Page (U Leicester), A. Y. Lien (GSFC/UMBC),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and M. H. Siegel (PSU)
report on behalf of the Swift Team:

At 01:05:16 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 161001A (trigger=714404).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 71.913, -57.283 which is 
   RA(J2000) = 04h 47m 39s
   Dec(J2000) = -57d 16' 57"
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 3 sec.  The peak count rate
was ~11000 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 01:06:21.5 UT, 65.0 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 71.91848, -57.26127 which is equivalent
to:
   RA(J2000)  = 04h 47m 40.44s
   Dec(J2000) = -57d 15' 40.6"
with an uncertainty of 3.9 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.  We
cannot determine whether the source is fading at the present time. No
spectrum from the promptly downlinked event data is yet available to
determine the column density. 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 68 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 K. L. Page (klp5 AT leicester.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: GRB161001A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19968
SUBJECT: GRB 161001A: Prompt enhanced Swift-XRT position
DATE:    16/10/01 01:44:27 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 161001A, we find an
enhanced XRT position of the afterglow: RA, Dec: 71.9194, -57.2604
which is equivalent to:
   RA (J2000)  = 04 47 40.66
   Dec (J2000) = -57 15 37.3
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/714404.

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: GRB161001A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19969
SUBJECT: GRB 161001A: Enhanced Swift-XRT position
DATE:    16/10/01 04:58:23 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 1075 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 161001A, 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 = 71.91991, -57.26095 which is equivalent
to:

RA (J2000): 04h 47m 40.78s
Dec (J2000): -57d 15' 39.4"

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: GRB161001A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19970
SUBJECT: GRB 161001A: Swift/UVOT Upper Limits
DATE:    16/10/01 11:40:49 GMT
FROM:    Paul Kuin at MSSL  <npkuin@gmail.com>

N. P. M. Kuin (UCL-MSSL) 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 161001A
68 s after the BAT trigger (Page et al., GCN Circ. 19967). No optical
afterglow consistent with the XRT position (Osborne et al. GCN Circ.
19969) 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         >20.8
u_FC               281          530          246         >20.2
white               68         1183          353         >20.4
v                  611         1232           78         >19.1
b                  536         1158           58         >19.1
u                  281         5994          395         >20.2
w1                 661         1282           78         >19.2
m2                 636         1257           78         >19.2
w2                1016         1208           39         >19.2

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: GRB161001A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19971
SUBJECT: GRB 161001A: X-shooter spectroscopy, candidate host galaxy and redshift
DATE:    16/10/01 12:57:15 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>

T. Kruehler (MPE Garching), D. Xu (NAOC/CAS), J. Bolmer (MPE Garching 
and ESO Santiago), K. Wiersema (Univ. Leicester), D. Malesani (DARK/NBI 
and DTU Space), R. Sanchez-Ramirez (IAA-CSIC), J. P. U. Fynbo 
(DARK/NBI), report on behalf of a larger collaboration:

We observed the field of GRB 1601001A (Page et al., GCN 19967) with the 
ESO Very Large Telescope Unit 2 (Kueyen) equipped with the X-shooter 
spectrograph.

Close to, but outside, the enhanced XRT position (Osborne et al., GCN 
19969), in our acquisition image we detect a bright, pointlike source at 
coordinates RA = 04:47:40.71, Dec = -57:15:36.8. This source is faintly 
visible in the archival DSS data and is pointlike in our images (0.75" 
seeing).

A spectrum was secured of this object, for a total of 4x600 s, starting 
on Oct 1.299 UT (6.1 hr after the GRB). The continuum is consistent with 
a stellar spectrum, and we conclude that this target is not associated 
with GRB 161001A.

Our slit, at a position angle of 319.6 deg (CCW from north), does 
however cover a portion of the XRT error circle. Within the wings of the 
the PSF of the DSS object, approximately 0.8 arcsec SE, we detect a 
number of emission lines which are consistent with [O II], Hbeta, [O 
III] and Halpha at a common redshift of z = 0.891, revealing the 
presence of a background object. While we cannot accurately determine 
its position from the slit information alone, that is consistent with 
being at the edge of the XRT error circle. Our images also hint a faint 
extension of the DSS object at a position consistent with that of the 
emission lines, which could represent the continuum emission of the 
object. As such, this is a candidate host galaxy of GRB 161001A.

We caution that we have no way to confirm the association between the 
emission line object and the GRB. No variability can be inferred from 
our data, and as we lack an estimate of the continuum flux, we can not 
presently quantify the chance association probability.

A finding chart showing the region surrounding the XRT position is shown 
at this URL: 
http://www.astro.ku.dk/~malesani/GRB/161001A/GRB161001A_slit.png

We acknowledge excellent support from the ESO observing staff at 
Paranal, in particular Zahed Wahhaj, Jonathan Smoker, and Claudia Cid.


GRB_name: GRB161001A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19972
SUBJECT: GRB 161001A: Swift-XRT refined Analysis
DATE:    16/10/01 14:20:05 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

We have analysed 6.9 ks of XRT data for GRB 161001A (Page et al. GCN
Circ. 19967), from 51 s to 34.6 ks after the  BAT trigger. The data
comprise 128 s in Windowed Timing (WT) mode (the first 7 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. 19968).

The late-time light curve (from T0+5.8 ks) can be modelled with a
power-law decay with a decay index of alpha=1.40 (+0.17, -0.16).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.07 (+0.16, -0.15). The
best-fitting absorption column is  4.9 (+0.9, -0.8) x 10^21 cm^-2, in
excess of the Galactic value of 1.1 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.90 (+/-0.16) and a
best-fitting absorption column of 6.5 (+1.2, -1.1) x 10^21 cm^-2. The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 4.6 x 10^-11 (7.4 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      6.5 (+1.2, -1.1) x 10^21 cm^-2
Galactic foreground: 1.1 x 10^20 cm^-2
Excess significance: 9.7 sigma
Photon index:      1.90 (+/-0.16)

If the light curve continues to decay with a power-law decay index of
1.40, the count rate at T+24 hours will be 5.4 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.5 x
10^-13 (4.0 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/00714404.

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


GRB_name: GRB161001A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19973
SUBJECT: GRB 161001A: Fermi GBM detection
DATE:    16/10/01 15:25:32 GMT
FROM:    Peter Veres at UAH  <veresp@gmail.com>

P Veres, M Stanbro and C Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 01:05:16.72 UT on 01 October 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 161001A (trigger 496976720 / 161001045) which
was also detected by the Swift/BAT (Page et al., GCN 19967).
The GBM on-ground location is consistent with the Swift position.


The angle from the Fermi LAT boresight at the GBM trigger time is 37
degrees.



The GBM light curve consists of a dominant pulse preceded by weaker emission
with a duration (T90) of about 2.2 s (50-300 keV).
The time-averaged spectrum from T0-1.1 s to T0+2.9 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.89 +/- 0.10 and
the cutoff energy, parameterized as Epeak, is 313 +/- 54 keV.

The event fluence (10-1000 keV) in this time interval is
(2.3 +/- 0.2)E-6 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.2 s in the 10-1000 keV band
is 6.9 +/- 0.3 ph/s/cm^2.


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


GRB_name: GRB161001A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19974
SUBJECT: GRB 161001A, Swift-BAT refined analysis (likely a short GRB)
DATE:    16/10/01 16:29:32 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),

J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC),

H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC),

J. P. Norris (BSU), 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-274 to T+962 sec from the recent telemetry downlink,

we report further analysis of BAT GRB 161001A (trigger #714404)

(Page, et al. GCN Circ. 19967).  The BAT ground-calculated position is

RA, Dec = 71.923, -57.261 deg which is

  RA(J2000)  =  04h 47m 41.5s

  Dec(J2000) = -57d 15' 39.8"

with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).

The partial coding was 78%.


The mask-weighted light curve shows several overlapping pulses

that stars at ~T-0.3, and ends at ~T+3 s. The highest peak occurs at

~ T+1.6 s. T90 (15-350 keV) is 2.6 +- 0.4 sec (estimated error including

systematics).


The time-averaged spectrum from T-0.2 to T+3.1 sec is best fit by a simple

power-law model.  The power law index of the time-averaged spectrum is

1.14 +- 0.09.  The fluence in the 15-150 keV band is 6.7 +- 0.4 x 10^-7 erg/cm2.

The 1-sec peak photon flux measured from T+1.40 sec in the 15-150 keV band

is 3.5 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence

level.


Using a 16-ms binned light curve, the lag analysis finds a lag of

7 (+/- 13) ms for the 100-350 keV to 25-50 keV band, and -7.5 (+26, -19) ms

for the 50-100 keV to 15-25 keV band, which is consistent with

those of a short GRB.


The results of the batgrbproduct analysis are available at

http://gcn.gsfc.nasa.gov/notices_s/714404/BA/


GRB_name: GRB161001A
Detection_method: GROND
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19975
SUBJECT: GRB 161001A: GROND afterglow candidate
DATE:    16/10/01 17:51:22 GMT
FROM:    Ting-Wan Chen at MPE  <jchen@mpe.mpg.de>

T.-W. Chen (MPE Garching), S. Klose, A. Nicuesa Guelbenzu (TLS), 
J. Bolmer (MPE Garching and ESO Vitacura), T. Kruehler and 
J. Greiner (both MPE Garching) report on behalf of the GROND team:

We observed the field of GRB 161001A (Swift trigger 714404; Page et
al., GCN #19967) simultaneously in g'r'i'z'JHK with GROND (Greiner
et al. 2008, PASP 120, 405) mounted at the 2.2m MPG telescope at the
ESO La Silla Observatory (Chile).

Observations started at 02:48 UT on 2016-10-01, 1.71 hours
after the GRB trigger. They were performed at an average 
seeing of 2" and at an average airmass of 2.3.

We found a faint singular point source which is south-west 2.2 arcsec 
away from the photometric center of nearby bright DSS2 object
for which Kruehler et al. (GCN #19971) reported X-Shooter spectroscopy.
The position is within the 2.3" Swift-XRT error circle reported by 
Evans et al. (GCN #19968) and also within the 1.9" enhanced XRT position 
(Osborne et al., GCN 19969), at
RA (J2000) = 04 h 47 m 40.57 s   
DEC (J2000) = -57d 15' 39.2
with an uncertainty of 0.5" in each coordinate.

Based on images with 36 min of total exposure in g'r'i'z'
and 30 min in JHK at a mid-time of 03:58 UT on 2016-10-01,
we derive the following preliminary magnitudes and upper limits
(all in the AB system):

g' = 23.1 +- 0.2 mag,
r' = 22.5 +- 0.1 mag,
i' = 21.6 +- 0.1 mag,
z' = 21.5 +- 0.1 mag,
J > 21.3 mag,
H > 20.3 mag, and
K > 18.7 mag.

Second-epoch observations were performed at a mean time 
of 09:19 UT at an average seeing 1.1" and at an average airmass of 1.1.
At that time the source seems to have faded to:

r' = 22.9 +- 0.1 mag

Given magnitudes are calibrated against USNO as well as 2MASS
field stars and are not corrected for the expected Galactic foreground
extinction corresponding to a reddening of E_(B-V) = 0.01 mag in the
direction of the burst (Schlafly & Finkbeiner 2011).


GRB_name: GRB161001A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19976
SUBJECT: GRB 161001A: MASTER-OAFA and MASTER-SAAO early optical observations
DATE:    16/10/02 10:08:33 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

R.Podesta, C.Lopez, F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA)

H. Levato, C. Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

D.Buckley, S. Potter,
South African Astronomical Observatory

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

R. Rebolo, M. Serra Ricart, N. Lodieu, G. Israelian
The Instituto de Astrofisica de Canarias

K.Ivanov, J.Rabinovich, N.M.Budnev,
Irkutsk State University

A. Tlatov, V.Senik, D. Dormidontov, A.Parkhomenko
Kislovodsk Solar Station of the Pulkovo Observatory

V.Yurkov, Yu.Sergienko, A.Gabovich
Blagoveschensk Educational State University, Blagoveschensk

MASTER-OAFA  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in OAFA was pointed to the  GRB161001A 29 sec after notice 
time and 41 sec after trigger time at 2016-10-01 01:05:57UT. On our 
first (10s exposure)  set we  not found OT within 6 square degrees 
field around  SWIFT BAT  error-box (Page et al., GCN 19967; Markwardt et 
al.,GCN 19974 ) brighter then 16.7  unfiltered magnitude.

MASTER-SAAO  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in SAAO was pointed to the  GRB161001A 167 sec after notice time 
and 176 sec after trigger time at 2016-10-01 01:08:17 UT. On our first 
(40s exposure)  set we haven't found optical transient  within SWIFT 
error-box.

The 5-sigma upper limit has been about 18.4 mag

We found optical object at first hour coadded images  by both MASTERs 
telescopes at coordinates Ra 04:47:40.83 Dec -57:15:38.07 (+-0.7 arcsec 
error) with unfiltered magnitude:

0.8R +0.2B = 20.6 (+0.1 -0.4)

with respect to USNO B stars. We  have archival images in MASTER SAAO 
DataBase at 2016-04-09  with 20.9 3-SIGMA limit. We see same object at 
same position.

We note that our scale is 1 pix ~ 2 arcsec . So the DSS2 object  (Kruehler 
et al., GCN 19971)  and GROND afterglow candidate (Chen et al., GCN 19975) 
are inside the our pixel.

The message may be cited.


GRB_name: GRB161001A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19977
SUBJECT: Konus-Wind observation of GRB 161001A (short/hard ?)
DATE:    16/10/02 11:46:33 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

D. Frederiks, S. Golenetskii, R.Aptekar, P. Oleynik, M. Ulanov,
D. Svinkin, A. Tsvetkova, A.Lysenko, A. Kozlova, and T. Cline,
on behalf of the Konus-Wind team, report:

GRB 161001A (Swift/BAT detection: Page et al., GCN 19967;
Fermi GBM observation: Veres et al., GCN 19973)
triggered Konus-Wind at T0=3919.479 s UT (01:05:19.479).

The light curve shows a short pulse with a total duration
of ~0.5 s.
The emission is seen up to ~5 MeV.

As observed by Konus-Wind, the burst had a fluence of
(1.8 Â± 0.5)x10^-6 erg/cm2 and a 16-ms peak energy flux,
measured from T0-0.016, of (8.0 Â± 3.5)x10^-6 erg/cm2
(both in the 20 keV - 10 MeV energy range).

The spectrum of the burst (measured from T0 to T0+0.256 s)
is best fit in the 20 keV - 10 MeV range by a cutoff power-law
(CPL) function with the following model parameters:
the photon index alpha = -0.46(-0.36,+0.48),
and the peak energy Ep = 437(-117,+190) keV,
chi2 = 30.0/36 dof.
Fitting this spectrum with the GRB (Band) function yields
the same alpha and Ep with only an upper limit on beta of -2.1,
chi2 = 30.0/35 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB161001_T03919/

All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.


GRB_name: GRB160927A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19978
SUBJECT: GRB 160927A: 15 GHz upper limits from AMI
DATE:    16/10/03 18:47:50 GMT
FROM:    Kunal Mooley at Oxford U  <kunal.mooley@physics.ox.ac.uk>

K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson 
(Curtin), T. Cantwell (Manchester), D. Titterington, S. H. Carey, J. 
Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), K. 
Grainge, A. Scaife (Manchester)

The AMI Large Array robotically triggered on the Swift alert for the 
short/hard GRB 160927A (Gibson et al., GCN 19952) as part of the 4pisky 
program, and subsequent follow up observations were obtained up to 3 
days post-burst. Our observations at 15 GHz on 2016 Sep 27.79, Sep 
28.70, and Sep 29.70 (UT; 1 hour, 23 hours, and 47 hours post-burst 
respectively) do not reveal any radio source at the XRT location (Page 
et al., GCN 19958), with 3sigma upper limits of 132 uJy, 119 uJy, and 
110 uJy respectively. The 3sigma upper limit from the first two epochs 
combined is 80 uJy.

We thank the AMI staff for scheduling these observations. The AMI-GRB 
database is a log of all GRB follow up observations with the AMI, and is 
available at http://4pisky.org/ami-grb/.


GRB_name: GRB161004A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19979
SUBJECT: GRB 161004A: Swift detection of a burst with a possible optical counterpart
DATE:    16/10/04 13:10:14 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

P.A. Evans (U Leicester), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), A. A. Breeveld (UCL-MSSL),
D. N. Burrows (PSU), A. D'Ai (INAF-IASFPA), V. D'Elia (ASDC),
J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC),
F. E. Marshall (NASA/GSFC), B. Mingo (U Leicester),
K. L. Page (U Leicester), P. Romano (INAF-IASFPA), T. Sakamoto (AGU),
B. Sbarufatti (INAF-OAB/PSU) and E. Troja (NASA/GSFC/UMCP) report on
behalf of the Swift Team:

At 12:58:28 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 161004A (trigger=715084).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 263.171, -0.928, which is 
   RA(J2000)  =  17h 32m 41s
   Dec(J2000) = -00d 55' 41"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a couple of peaks
with a total duration of about 5 sec.  The peak count rate
was ~1800 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 12:59:49.3 UT, 80.7 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 263.15298, -0.94831 which is equivalent
to:
   RA(J2000)  = 17h 32m 36.72s
   Dec(J2000) = -00d 56' 53.9"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 97 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 in excess of the Galactic value (1.88 x
10^21 cm^-2, Willingale et al. 2013), with an excess column of 4.1
(+3.92/-2.99) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 85 seconds after the BAT trigger. There is a candidate afterglow in
the list of sources generated on-board at
  RA(J2000)  = 17:32:36.59 = 263.15244
  DEC(J2000) = -00:57:02.2  =  -0.95061
with a 90%-confidence error radius of about 1.10 arc sec. This position is 6.6
arc sec. from the center of the XRT error circle. The estimated magnitude is
19.03. No correction has been made for the expected extinction corresponding to
E(B-V) of 0.25. 

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: GRB161004A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19980
SUBJECT: GRB 161004A: TSHAO optical observations
DATE:    16/10/04 17:44:41 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI), I. Reva (Fesenkov Astrophysical Institute), A. Kusakin 
(Fesenkov Astrophysical Institute),  A. Volnova (IKI), A. Pozanenko 
(IKI) report on behalf of larger GRB follow-up collaboration:

We observed the field of GRB 161004A  (Evans  et al., GCN 19979)  with 
Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical Observatory. 
We obtained several images in R filter starting on Oct. 04 (UT) 
13:36:52.  In the XRT error circle we do not detect any new object. Wa 
do not detect also candidate afterglow (Evans  et al., GCN 19979). 
Preliminary photometry of a combined image is following

Date       UT start   t-T0   Filter   Exp.  OT     Err.  UL
                       (mid, days)     (s)
2016-10-04 13:36:52 0.04321  R       15*180 n/d    n/d   21.9

Photometry is based on nearby SDSS-DR9 stars (Lupton transformations):
SDSS-DR9_id         R(Lupton)
J173243.09-005731.3 17.04
J173250.91-005842.7 16.77
J173251.94-005803.2 15.75
J173253.88-005801.6 15.62
J173253.02-005938.3 16.02
J173232.00-005640.3 16.34
J173227.11-005646.8 16.41
J173227.04-005816.8 16.51
J173227.48-005856.9 16.62
J173236.27-010018.1 16.96
J173241.54-005823.1 16.26

A finding chart can be found at 
http://grb.rssi.ru/GRB161004A/GRB161004A_TSHAO_161004_XRT_UVOT.png


GRB_name: GRB161004A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19981
SUBJECT: GRB 161004A: Bassano Bresciano Observatory upper limit
DATE:    16/10/04 19:14:38 GMT
FROM:    Ulisse Quadri at Bassano Bresciano Obs  <oabb@ulisse.bs.it>

U.Quadri, L.Strabla and R.Girelli report:

We imaged the field of GRB 161004A detected by SWIFT(trigger 715084)
with the robotic telescope of (IAU station 565) Bassano Bresciano 
Observatory, Italy. Member of: 
AAVSO - American Association of Variable Star Observers.
ISSP - Italian Supernovae Search Project.
UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili.

The observations started 4.90 hour after the GRB trigger, at the end of twilight, 
with our Newton telescope D=250 mm F/D=4.8.

Weather conditions were good.

We co-added 3 series of 10 exposures of 60 sec each.

Start T0+      End T0+      Vlim
4.9 hour       5.5 hour        18

We did not found any optical counterpart in the error box of the XRTcandidate.
P.A. Evans (U Leicester), S. D. Barthelmy (GSFC), et al.

Magnitudes were estimated with the UCAC4 cat. and 
are not corrected for galactic dust extinction.

Reference:
http://www.osservatoriobassano.org/GRB.asp

The message may be cited.


GRB_name: GRB161004A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19983
SUBJECT: GRB 161004A: Enhanced Swift-XRT position
DATE:    16/10/04 20:50:17 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 4971 s of XRT Photon Counting mode data and 10 UVOT
images for GRB 161004A, 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 = 263.15236, -0.95067 which is equivalent
to:

RA (J2000): 17h 32m 36.57s
Dec (J2000): -00d 57' 02.4"

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: GRB161004A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19984
SUBJECT: GRB 161004A: Swift/UVOT Detection
DATE:    16/10/04 21:15:33 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 161004A
85 s after the BAT trigger (Evans et al., GCN Circ. 19979).
A source consistent with the enhanced XRT position (Beardmore et al., 
GCN Circ. 19983) is detected in the initial UVOT exposures in the white 
and u filters only.

The preliminary UVOT position is:
     RA  (J2000) =  17:32:36.54 = 263.15224 (deg.)
     Dec (J2000) = -00:57:02.7  =  -0.95075 (deg.)
with an estimated uncertainty of 0.56 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               85          235          147         19.47 Â± 0.16
v                  627         6121          432        >20.1
b                  552        10926         1144        >21.8
u                  297          547          246         19.55 Â± 0.29
w1                 848         6531          413        >20.2
m2                4690         6326          393        >20.3
w2                 602        12506         1063        >20.8

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening of E(B-V) = 0.25 in the direction of the 
burst (Schlegel et al. 1998).


GRB_name: GRB161004A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  19985
SUBJECT: GRB 161004A: Swift-XRT refined Analysis
DATE:    16/10/04 21:47:28 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), B. Sbarufatti (INAF-OAB/PSU),
D.N. Burrows (PSU), T.G.R. Roegiers (PSU), A.P. Beardmore (U.
Leicester), S.L. Gibson (U. Leicester), A. D'Ai (INAF-IASFPA) and P.A.
Evans report on behalf of the Swift-XRT team:

We have analysed 6.1 ks of XRT data for GRB 161004A (Evans et al. GCN
Circ. 19979), from 84 s to 18.2 ks after the  BAT trigger. The data
comprise 112 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Beardmore et al. (GCN Circ. 19983).

The late-time light curve (from T0+4.3 ks) can be modelled with a
power-law decay with a decay index of alpha=1.3 (+0.5, -0.4).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.94 (+0.11, -0.09). The
best-fitting absorption column is  consistent with the Galactic value
of 1.9 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has
a photon index of 1.59 (+0.18, -0.16) and a best-fitting absorption
column of 2.2 (+0.9, -0.4) x 10^21 cm^-2. The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum  is 4.6 x 10^-11 (5.5 x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      2.2 (+0.9, -0.4) x 10^21 cm^-2
Galactic foreground: 1.9 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.59 (+0.18, -0.16)

If the light curve continues to decay with a power-law decay index of
1.3, the count rate at T+24 hours will be 1.1 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.9 x
10^-14 (5.9 x 10^-14) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00715084.

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


