# GCN_circulars

GRB_name: GRB170519A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21114
SUBJECT: GRB 170519A: Swift-XRT refined Analysis
DATE:    17/05/19 16:20:48 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

S. J. LaPorte (PSU), K.L. Page (U. Leicester), B. Mingo (U. Leicester),
A.P. Beardmore (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri
(INAF-OAB), P. D'Avanzo (INAF-OAB), J.A. Kennea (PSU), B. Sbarufatti
(INAF-OAB/PSU) and T.N. Ukwatta report on behalf of the Swift-XRT team:

We have analysed 9.5 ks of XRT data for GRB 170519A (Ukwatta et al. GCN
Circ. 21106), from 73 s to 23.1 ks after the  BAT trigger. The data
comprise 291 s in Windowed Timing (WT) mode (the first 6 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Beardmore
et al. (GCN Circ. 21107).

The late-time light curve (from T0+4.1 ks) can be modelled with a
power-law decay with a decay index of alpha=0.94 (+/-0.08).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.62 (+/-0.05). The
best-fitting absorption column is  1.78 (+0.12, -0.11) x 10^21 cm^-2,
in excess of the Galactic value of 2.4 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.98 (+/-0.10) and a
best-fitting absorption column of 1.20 (+0.29, -0.27) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 3.4 x 10^-11 (4.3 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.20 (+0.29, -0.27) x 10^21 cm^-2
Galactic foreground: 2.4 x 10^20 cm^-2
Excess significance: 5.8 sigma
Photon index:      1.98 (+/-0.10)

If the light curve continues to decay with a power-law decay index of
0.94, the count rate at T+24 hours will be 0.030 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.0 x
10^-12 (1.3 x 10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00753445.

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


GRB_name: GRB170519A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21115
SUBJECT: GRB 170519A: KAIT Optical Observations
DATE:    17/05/19 18:44:38 GMT
FROM:    Weikang Zheng at UC Berkeley  <weikang@berkeley.edu>

WeiKang Zheng, Max Genecov, and Alex Filippenko (UC Berkeley) report on
behalf of the KAIT GRB team:

The 0.76-m Katzman Automatic Imaging Telescope (KAIT) at
Lick Observatory responded to Swift GRB 170519A (Ukwatta et al.,
GCN 21106) starting at 05:14:24 UT, 262s after the burst.
Observations were performed with an automatic sequence in the
V, I, and clear (roughly R) filters, and the exposure time was
20 s per image, observations lasted about 2 hours.
The optical afterglow (Ukwatta et al., GCN 21106; Izzo et al.,
GCN 21108; Butler et al., GCN 21109; Guidorzi et al., GCN 21110;
Xu et al., GCN 21111; Hentunen & Nissinen, GCN 21113) was well
detected in our V, I and clear filter images. A preliminary
analysis shows that the afterglow rises at early time and peaked
around 1 ks. After 3 ks after the burst, the light curve can be
fitted by a power law with index of -0.83.
A preliminary light curve is posted at:
http://astro.berkeley.edu/~zwk/grb/GRB170519A/GRB170519A_kait.png


GRB_name: GRB170519A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21117
SUBJECT: GRB 170519A: BOOTES-5/JGT early optical detection
DATE:    17/05/19 22:58:31 GMT
FROM:    Alberto Castro-Tirado at Inst.de Astro. de Andalucia  <ajct@iaa.es>

A. J. Castro-Tirado (IAA-CSIC & ISA-UMA), J. C. Tello, R. Cunniffe, 
B.-B. Zhang, Y. Hu and A. Gonzalez-Rodriguez (IAA-CSIC), A. Castellon 
(Univ. de Malaga), D. Hiriart, W. H. Lee (UNAM), S. Jeong and I. H. Park (SKKU)
and P. Kubanek (Inst. of Physics, CZ) on behalf of a larger collaboration, report:

The 60 cm BOOTES-5/Javier Gorosabel Telescope at Observatorio 
AstronÃ³mico Nacional in San Pedro MÃ¡rtir (MÃ©xico) automatically 
responded to the Swift trigger of GRB 170519A (Ukwatta et al., GCN 
21106). The first unfiltered images (60 s exposures) were obtained at 
05:15:08.9 UT (5 min after the burst). At the position of the Swift 
X-ray afterglow, we confirm the optical afterglow detected by UVOT, at a 
magnitude of 16.6+/-0.1 when compared to the GSC2.3 catalog, and fading 
during the late-time BOOTES-5/JGT observation.

We thank the staff at Observatorio AstronÃ³mico Nacional in San Pedro 
MÃ¡rtir for its excellent support.

[GCN OPS NOTE(19may17),  At the request of the author, the last 3 authors
were added.]


GRB_name: GRB170519A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21118
SUBJECT: GRB170519A, Swift-UVOT Detection
DATE:    17/05/19 23:24:09 GMT
FROM:    Sam LaPorte at PSU  <sjl5346@psu.edu>

GRB 170519A: Swift/UVOT Detection

S. J. LaPorte (PSU) and T. N. Ukwatta (LANL)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 170519A
93 s after the BAT trigger (Ukwatta et al., GCN Circ. 21106).
A fading source consistent with the XRT position
(Beardmore et al. GCN Circ. 21107)
is detected in all initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  10:53:42.45 = 163.42688 (deg.)
    Dec (J2000) = +25:22:27.5  =  25.37431 (deg.)
with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).

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

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

white              5315          5515         196          17.22+-0.03  
white               582           773          38          16.25+-0.04
white                89           239         147          16.91+-0.03
v                    68          5926         421          17.46+-0.08  
b                   557          6594         282          17.66+-0.05
u                   302           552         245          16.00+-0.04   
uvw1                680          6337         412          16.76+-0.05 
uvm2               5932          6131         196          17.13+-0.11   
uvw2                607           627          19          16.45+-0.20  

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


GRB_name: GRB170519A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21119
SUBJECT: GRB 170519A: Redshift from GTC/OSIRIS
DATE:    17/05/19 23:43:59 GMT
FROM:    Luca Izzo at IAA-CSIC  <Luca.Izzo@ICRA.it>

L. Izzo (IAA-CSIC), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), D.A. Kann (IAA-CSIC), C.C. Thoene (IAA-CSIC), P. Pessev (GTC, IAC) and A. Tejero (GTC) report on behalf of a larger collaboration:

We observed the afterglow of the GRB 170519A (Ukwatta et al., GCN 21106) using OSIRIS on the 10.4m GTC at the Roque de los Muchachos observatory (La Palma, Spain). The observation consisted of 3x1200s exposures using the R1000B grism, covering the range between 3700 and 7800 AA. The first spectrum started at 21:23 UT (16.22 hr after the burst).

We detect clear absorption features due to Mg II, Mg I, Fe II, Fe II* and Ca II H&K lines at the common redshift of z = 0.818, which we identify as the redshift of the GRB.


GRB_name: GRB170519A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21120
SUBJECT: GRB 170519A: NOT optical observations
DATE:    17/05/19 23:53:45 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), D. Xu (NAOC), 
D. Malesani (DARK/NBI), K.E. Heintz (DARK/NBI), 
D. Gandolfi (Univ. Turin), and J. Telting (NOT) report on behalf 
of a larger collaboration,

We have observed the field of GRB 170519A (Ukwatta et al., 
GCN 21106) with the 2.5m Nordic Optical Telescope at La 
Palma (Spain). The observations consisted of 3x120s in V-band 
and 5x120s in Sloan i-band. The GRB afterglow is well detected in 
all the individual frames. On an image starting at 21:51 UT (16.68 hr 
after the burst) we detect the optical afterglow at i(AB) = 19.7 mag, 
as compared to SDSS field stars. This confirms the t^(-0.8) decay 
reported by Butler et al. (GCN 21109) and by Zheng et al. 
(GCN 21115) that started 900 s after the GRB trigger.


GRB_name: GRB170519A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21121
SUBJECT: GRB 170519A: MITSuME Okayama Optical Observation
DATE:    17/05/20 05:01:54 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 (Subaru, NAOJ), K. Ohta (Kyoto)
and N. Kawai(Tokyo Tech)
report on behalf of the MITSuME and OISTER collaboration:

We observed the field of GRB 170519A (Ukwatta et al., GCNC 21106)
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 2017-05-19 11:03:26 UT (~5.9 h after
the burst). We detected the previously reported afterglow (Ukwatta
et al., GCNC 21106; Izzo et al., GCNC 21108) in all the three bands.

Photometric results of the OT are listed below. We used SDSS-DR8
catalog for flux calibration.

#T0+[day]  MID-UT    T-EXP[sec]   g'  g'_err  Rc  Rc_err  Ic  Ic_err
------------------------------------------------------------------
0.26646    11:33:44    3120.0    19.1  0.2   18.7 0.2   18.1  0.2
------------------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]


GRB_name: GRB170519A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21122
SUBJECT: GRB 170519A: Continued RATIR Optical and NIR Observations
DATE:    17/05/20 14:32:57 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), JesÃºs
GonzÃ¡lez (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM), Harvey Moseley (GSFC), John
Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:

We observed the field of GRB 170519A (Ukwatta,, et al., GCN 21106) 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 2017/05 20.16 to 2017/05 20.32 UTC (22.66 to
26.62 hours after the BAT trigger), obtaining a total of 2.49 hours
exposure in the r and i bands and 0.97 hours exposure in the Z, Y, J, and H
bands.

In comparison with the SDSS DR9 and 2MASS catalogs, we obtain the following
detections of the optical transient:

  r = 20.57 +/- 0.01
  i = 20.39 +/- 0.01
  Z = 20.05 +/- 0.04
  Y = 20.15 +/- 0.05
  J = 20.02 +/- 0.06
  H = 19.72 +/- 0.07

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
Martir.


GRB_name: GRB170519A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21123
SUBJECT: GRB 170519A: Watcher optical observations
DATE:    17/05/20 18:31:58 GMT
FROM:    Antonio Martin-Carrillo at UCD,Space Science Group  <antonio.martin-carrillo@ucd.ie>

A. Martin-Carrillo (UCD), D. Murphy (UCD), L. Hanlon (UCD), H. J. van Heerden (UFS), B. van Soelen (UFS) and P. J. Meintjes (UFS)

We observed the field of GRB 170519A (Ukwatta, et al., GCN 21106 using the 40cm UCD Watcher telescope at Boyden Observatory in South Africa.

Observations started on May 19th at 16:30 UT (T0+11.5h) and consisted of a series of 20s exposures in SDSS râ€™ filter for a total monitoring time of 3 hours. Based on combined images with mid-time at 17:00 UT, we derive a preliminary magnitude of râ€™=19.3 +/- 0.3 (AB system).

Magnitudes were calibrated using 2 nearby APASS stars. No correction for Galactic extinction in the direction of the GRB has been applied.


GRB_name: GRB170519A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21124
SUBJECT: GRB 170519A: MITSuME Akeno Optical Observation
DATE:    17/05/22 06:07:27 GMT
FROM:    Taketoshi Yoshii at Tokyo Tech  <yoshii.t.ac@m.titech.ac.jp>

K. Morita, Y. Saito, R. Itoh, T. Yoshii, Y. Tachibana, S. Harita, Y. Muraki, 
T. Ozawa, K. Shiraishi, H. Mamiya, Y. Yatsu, and N. Kawai
(Tokyo Tech)

report on behalf of the MITSuME collaboration:

We searched for the optical counterpart of GRB 170519A (T. N. Ukwatta et al., GCN Circular #21106) 
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 2017-05-19 11:03:14 UT (21192 sec after the burst).
We detected the optical counterpart (T. N. Ukwatta et al., GCN Circular #21106) in g', Rc and Ic band.
The measured magnitudes were listed as follows.

T0+[hour]  MID-UT    T-EXP[sec]     g'         Rc              Ic   
----------------------------------------------------------------------------
~5.9       11:34:54  4278  $B!!!!(B19.14+/-0.15     18.48+/-0.11    18.13+/-0.13
----------------------------------------------------------------------------

T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.


GRB_name: GRB170514A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21125
SUBJECT: GRB 170514A CALET Gamma-Ray Burst Monitor detection
DATE:    17/05/22 11:59:25 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

S. Matsukawa, A. Yoshida, T. Sakamoto, Y. Kawakubo, M. Moriyama,
Y. Yamada, A. Tezuka (AGU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
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), A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long-duration GRB 170514A (Bissaldi et al., GCN Circ. 21094;
Konus-Wind trigger time on 04:18:42.056 UT) triggered the CALET
Gamma-ray Burst Monitor (CGBM) at 04:19:59.08 on 14 May 2017.
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.  Note that the CGBM
triggered at the 2nd bright burst episode which was ~1 min after the
initial peak.

The light curve of the SGM shows two separated peaks.  The initial peak,
which triggered Fermi-GBM and Konus-Wind, shows the emission around T-70 sec.
The 2nd peak starts from T-1 sec, peaks at T+0 sec and ends at T+10 sec.
The T90 duration measured by the SGM data is 7.8 +- 0.6 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1178770293/

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


GRB_name: GRB170522A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21126
SUBJECT: GRB 170522A: Fermi GBM detection
DATE:    17/05/23 00:30:48 GMT
FROM:    Matthew Stanbro at UAH/Fermi  <mcs0001@uah.edu>

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

"At 15:45:35.28 UT on 22 May 2017, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 170522A (trigger 517160740 / 170522657).
The on-ground calculated location, using the GBM trigger
data, is RA = 135.45, DEC = 27.12, with an uncertainty
of 1.0 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 50 degrees.

The GBM light curve consists of 1 peak
with a duration (T90) of about 7 s (50-300 keV).
The time-averaged spectrum from T0-0.00 s to T0+8.32 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.41 +/- 0.02 and
the cutoff energy, parameterized as Epeak, is 344 +/- 8 keV.

The event fluence (10-1000 keV) in this time interval is
(2.31 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+3.58 s in the 10-1000 keV band
is 23.35 +/- 0.37 ph/s/cm^2.

A Band function fits the spectrum equally well
with Epeak= 314 +/- 11 keV, alpha = -0.36 +/- 0.03 and beta = -2.63 +/-
0.15.


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


GRB_name: GRB170522A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21127
SUBJECT: GRB 170522A: Fermi-LAT detection
DATE:    17/05/23 01:46:11 GMT
FROM:    Judith Racusin at GSFC  <judith.racusin@nasa.gov>

M. Arimoto (Waseda University) and J. L. Racusin (NASA/GSFC) report on behalf 
of the Fermi-LAT team:

At 15:45:35.28 on May, 22, 2017 Fermi-LAT detected high-energy emission from GRB 
170522A, which was also detected by Fermi-GBM (trigger 517160740 / 170522657, 
Stanbro et al., GCN 21126). 

The best LAT on-ground location is found to be
RA, Dec = 139.34, 25.67 (J2000)
with an error radius of 0.19 deg (90 % containment, statistical error only). 

This was 50 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 GBM trigger with 
high significance.  The highest-energy photon is a 3.7 GeV event which is observed 8 
seconds after the GBM trigger.

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: GRB170522A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21128
SUBJECT: GRB 170522A: Tiled Swift observations
DATE:    17/05/23 02:43:18 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift has initiated a series of observations, tiled on the sky, of the
Fermi/LAT GRB 170522A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00068

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.


GRB_name: GRB170522A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21129
SUBJECT: Konus-Wind observation of GRB 170522A
DATE:    17/05/23 10:54:42 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 long GRB 170522A (Fermi-GBM detection: Stanbro & Meegan,
GCN 21126; Fermi-LAT detection: Arimoto & Racusin, GCN 21127)
triggered Konus-Wind at T0=56735.921 s UT (15:45:35.921)

The burst light curve shows a multi-peaked pulse with
a total duration of ~7.4 s.
The emission is seen up to ~10 MeV.

As observed by Konus-Wind, the burst had a fluence of
(3.8 Â± 0.4)x10^-5 erg/cm2 and a 64-ms peak energy flux,
measured from T0+2.048 s of (1.41 Â± 0.14)x10^-5 erg/cm2
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+13.568 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.48 (-0.20,+0.22),
the high energy photon index beta = -2.42 (-0.38,+0.20),
the peak energy Ep = 289 (-37,+49) keV,
chi2 = 97/97 dof.

The spectrum near the peak count rate (measured from T0 to T0+5.376 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.39 (-0.17,+0.20),
the high energy photon index beta = -2.49 (-0.31,+0.19),
the peak energy Ep = 312 (-36,+42) keV,
chi2 = 88/97 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB170522_T56735/

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


GRB_name: GRB170522B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21130
SUBJECT: IPN Triangulation of GRB 170522B (long/intense)
DATE:    17/05/23 14:48:31 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,

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 long-duration, intense GRB 170522B has been detected by
Konus-Wind, Mars-Odyssey (HEND), and INTEGRAL (SPI-ACS),
so far, at about 84124 s UT (23:22:04).

We have triangulated it to a preliminary,
3 sigma error box whose coordinates are:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
   159.268 (10h 37m 04s) -34.716 (-34d 42' 56")
  Corners:
   158.845 (10h 35m 23s) -35.550 (-35d 32' 58")
   158.818 (10h 35m 16s) -35.346 (-35d 20' 45")
   159.689 (10h 38m 45s) -33.872 (-33d 52' 21")
   159.715 (10h 38m 52s) -34.080 (-34d 04' 47")
  ---------------------------------------------
The error box area is 644 sq. arcmin, and its maximum
dimension is 1.82 deg (the minimum one is 6.6 arcmin).
The Sun distance was 109 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB170522_T84124/IPN/

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


GRB_name: GRB170522B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21131
SUBJECT: Konus-Wind observation of GRB 170522B
DATE:    17/05/23 14:58:06 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 long/intense GRB 170522B (IPN triangulation:
Hurley et al., GCN 21130) triggered Konus-Wind
at T0=84124.494 s UT (23:22:04.494)

The burst light curve shows a weak count rate increase (from
~T0-187s to ~T0-167s) followed by a bright, multi-peaked pulse
which started at ~T0-30 s an had a total duration of ~87 s.
The emission is seen up to ~10 MeV.

As observed by Konus-Wind, the burst had a fluence of
(1.75 Â± 0.11)x10^-4 erg/cm2 and a 64-ms peak energy flux,
measured from T0+8.640 s of (2.36 Â± 0.24)x10^-5 erg/cm2
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+55.040 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -1.16 (-0.05,+0.06),
the high energy photon index beta = -2.15 (-0.09,+0.07),
the peak energy Ep = 252 (-24,+26) keV,
chi2 = 89/97 dof.

The spectrum near the peak count rate (measured from T0+8.448
to T0+9.472 s) is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.68 (-0.15,+0.16),
the high energy photon index beta = -2.29 (-0.31,+0.16),
the peak energy Ep = 343 (-53,+79) keV,
chi2 = 75/72 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB170522_T84124/

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


GRB_name: GRB170522A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21132
SUBJECT: GRB 170522A: Global MASTER-Net job 
DATE:    17/05/23 18:17:37 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, D.Kuvshinov, A.V.Krylov,
I.Gorbunov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University, Sternberg Astronomical Institut of MSU

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

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

R.Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA) , 
National University of San Juan, Argentina

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

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

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

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

MASTER Tunka  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in Tunka was pointed to the  GRB170522A  36 sec after notice time 
and 136 sec after trigger time at 2017-05-22 15:47:51 UT. On our first 
(30s exposure)  set we  do not OT within GBM 
FERMI  error-box  (ra=135.417 dec=27.0394 r=1.26 see Stanbro and Meegan 
GCN #21126 ) brighter then 16.2.

Unfortunately this observation was outside of the future Fermi LAT 
(Arimoto and  Racusin, GCN #21127) error box.

Fortunatelly, we have MASTER Very Wide field cameras on all telescopes 
(5-10 
sec exposure on  2x380 square degrees FOV) and we have images with future 
Fermi LAT (Arimoto and  Racusin, GCN #21127) error box.  There is no OT 
brighter ~12 mag inside the future Fermi LAT error box.

The observations made on zenit distance = 66 degrees, galaxy latitude b = 
40 degree. The moon (14 % bright part) below the horizon (The altitude of 
the Moon is  -32 degree ). Observations started at twilight.
The sun  altitude  is -15.9 degree.
The area can be observed till sunrise at 2017-05-22 21:04:48

MASTER SAAO  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in SAAO was automaticaly starting survey on the FERMI  GRB170522A 
error-box (ra=09 01 47 dec=+27 07 12 r=1 Fermi GBM error box Stanbro and 
Meegan GCN #21126 )  3186 sec after 
notice time and 3740 sec  after trigger time at 2017-05-22 16:47:55 UT. 
The 5-sigma upper limit on  our first (60s exposure)  set is about 18.7mag
No OT brighter 19.5 detected in SAAO.

The observations made on zenit distance = 62 degrees, galaxy latitude b = 
40 degree.
The moon (14 % bright part) below the horizon (The altitude of the Moon is 
-39 degree ).
Observations started at twilight.
The sun  altitude  is -13.9 degree.
The object can be observed till sunrise at 2017-05-23 05:22:11

Unfortunately this observation was outside of the future Fermi LAT
(Arimoto and  Racusin, GCN #21127) error box.

MASTER-OAFA   robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in OAFA automaticaly was pointed to the  GRB170522A 247 sec after 
FERMI LAT notice time (Arimoto and Racusin, GCN #21127)  and 35103 
sec after trigger time at 2017-05-23 01:30:38 UT .
But zenit distance was very high and we received dark images.

On  our 4-th image (923 sec after FERMI
LAT notice time (Arimoto and Racusin, GCN #21127)  and 35779
sec after trigger time at 2017-05-23 01:41:54 UT.)  we 
found 1 short optical transient within LAT 
error-box  (ra=139.338 dec=25.67 r=0.19) brighter then 14.5 .


  T-Tmid      Date      Time       Expt.        Ra                Dec           Mag
---------|---------------------|-------|-----------------|-----------------|-------
    35869   2017-05-23 01:41:54     180   (  9h 16m 35.3s , +25d 41m 07.4s)    13.72


This object was found only on the one image.
The 5-sigma upper limit has been about 14.5 mag
We did not find OT brighter 18.5 on the next images.

The observations made on zenit distance = 80 degrees, galaxy latitude b = 
43 degree. The moon (11 % bright part) below the horizon (The altitude of 
the Moon is -63 degree ). The sun  altitude  is -50.3 degree.
The object can be observed till 2017-05-23 02:44:45 .



The message may be cited.


GRB_name: GRB170522A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21133
SUBJECT: GRB 170522A: Swift-XRT observations
DATE:    17/05/24 13:51:04 GMT
FROM:    Sarah Gibson at U.of Leicester  <slg44@leicester.ac.uk>

B. Mingo (U. Leicester), A.P. Beardmore (U. Leicester), 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) 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 170522A (Arimoto et al. GCN Circ. 21127)
in a series of observations tiled on the sky. The total exposure time
is 4.7 ks, distributed over 5 tiles; the maximum exposure at a single
sky location was 3.3 ks. The data were collected between T0+39.4 ks and
T0+51.3 ks, and are entirely in Photon Counting (PC) mode. 

Four uncatalogued X-ray sources have been detected, however none of
them is above the RASS limit or shows definitive signs of fading.
Therefore, at the present time we cannot identify which, if any, is the
afterglow. Details of these sources are given below:

Source 1:
  RA (J2000):  139.1534  =  09:16:36.82
  Dec (J2000): +25.4844  =  +25:29:03.9
  Error: 3.8 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: (9.7 [+3.1, -2.6])e-3 ct s^-1   
  Distance: 901 arcsec from Fermi/LAT position.
  Flux: (4.2 [+1.3, -1.1])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 2:
  RA (J2000):  139.2381  =  09:16:57.13
  Dec (J2000): +25.4737  =  +25:28:25.5
  Error: 6.0 arcsec (radius, 90% conf.)
  Count-rate: (6.7 [+3.3, -2.5])e-3 ct s^-1   
  Distance: 780 arcsec from Fermi/LAT position.
  Flux: (4.4 [+2.2, -1.6])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 3:
  RA (J2000):  139.1099  =  09:16:26.38
  Dec (J2000): +25.8756  =  +25:52:32.2
  Error: 6.5 arcsec (radius, 90% conf.)
  Count-rate: (6.6 [+2.9, -2.2])e-3 ct s^-1   
  Distance: 1050 arcsec from Fermi/LAT position.

Source 4:
  RA (J2000):  139.0535  =  09:16:12.85
  Dec (J2000): +25.6179  =  +25:37:04.5
  Error: 10.2 arcsec (radius, 90% conf.)
  Count-rate: (5.6 [+3.1, -2.3])e-3 ct s^-1   
  Distance: 948 arcsec from Fermi/LAT position.

The results of the XRT-team automatic analysis of the tiled XRT
observations, including a position-specific upper limit calculator, are
available at http://www.swift.ac.uk/xrt_products/TILED_GRB00068.

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


GRB_name: GRB170522A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21134
SUBJECT: GRB 170522A: LCO McDonald observations
DATE:    17/05/24 14:52:51 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

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

We began observing Fermi-LAT GRB 170522A (Arimoto et al. GCN 21127; 
Stanbro et al. GCN 21126; Lipunov et al. GCN 21132) on May 23, 03:07 UT 
(11.4 hours since the GRB) with the 1-m LCO unit at the LCO McDonald 
observatory with the SDSS i filter. Within the LAT error circle we do 
not detect any uncatalogued source down to i~19 mag in a 3x120s stacked 
frame, as calibrated against nearby SDSS stars.
Although all of the four X-ray sources reported by Swift-XRT (Mingo et 
al. GCN 21133) lie outside the LAT error circle, three of them (Sources 
1, 2, 3) happen to lie within our field of view. We did not find 
uncatalogued counterparts in any of the corresponding error circles down 
to the same limit.


GRB_name: GRB170524A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21135
SUBJECT: GRB 170524A: Swift detection of a burst (or possible new SGR)
DATE:    17/05/24 20:06:28 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

J.G. Gropp (PSU), S. D. Barthelmy (GSFC), C. Gronwall (PSU),
J. A. Kennea (PSU), H. A. Krimm (NSF/USRA), N. P. M. Kuin (UCL-MSSL),
A. Y. Lien (GSFC/UMBC) and D. M. Palmer (LANL) report on behalf of the
Swift Team:

At 19:49:15 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 170524A (trigger=754322).  Swift slewed immediately to the source. 
The BAT on-board calculated location is 
RA, Dec 319.456, +48.587, which is 
   RA(J2000)  =  21h 17m 49s
   Dec(J2000) = +48d 35' 15"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a single peak
with a duration of about 0.25 sec.  The peak count rate
was ~3000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 19:50:16.0 UT, 60.7 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 319.4869, 48.6065 which
is equivalent to:
   RA(J2000)  = 21h 17m 56.86s
   Dec(J2000) = +48d 36' 23.4"
with an uncertainty of 4.1 arcseconds (radius, 90% containment). This
location is 101 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 does not constrain the column density. 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 67 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. 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. 

We note that this is a short burst, close to the Galactic plane 
(lat = -0.5 degrees), although far from the Galactic center
(lon = 91 degrees).  Thus there is a possibility that this
is a previously unknown Soft Gamma Repeater (SGR). 
However, the preliminary 4-energy lightcurve shows more
flux above 100 keV than is typical for an SGR burst. 

Burst Advocate for this burst is J.G. Gropp (jdg44 AT 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: GRB170524A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21136
SUBJECT: GRB 170524A: Enhanced Swift-XRT position
DATE:    17/05/25 03:30:05 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Using 467 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 170524A, 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 = 319.48641, +48.60687 which is equivalent
to:

RA (J2000): 21h 17m 56.74s
Dec (J2000): +48d 36' 24.7"

with an uncertainty of 4.3 arcsec (radius, 90% confidence).

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

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


GRB_name: GRB170511A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21137
SUBJECT: GRB 170511A: MAXI/GSC detection
DATE:    17/05/25 03:48:58 GMT
FROM:    Motoko Suzuki at RIKEN  <motoko@crab.riken.jp>

Y. Takao, M. Serino, S. Nakahira (RIKEN), S. Sugita (Tokyo Tech), H. Negoro (Nihon U.),
S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N. Isobe (JAXA),
T. Mihara, M. Sugizaki, W. Iwakiri, M. Shidatsu, M. Matsuoka (RIKEN),
N. Kawai, T. Yoshii, Y. Tachibana, S. Harita, Y. Muraki, K. Morita (Tokyo Tech),
A. Yoshida, T. Sakamoto, Y. Kawakubo, Y. Kitaoka, T. Hashimoto (AGU),
H. Tsunemi, T. Yoneyama (Osaka U.),
M. Nakajima, T. Kawase, A. Sakamaki (Nihon U.),
Y. Ueda, T. Hori, A. Tanimoto, S. Oda (Kyoto U.),
Y. Tsuboi, Y. Nakamura, R. Sasaki (Chuo U.),
M. Yamauchi, C. Hanyu, K, Hidaka (Miyazaki U.),
T. Kawamuro (NAOJ),
K. Yamaoka (Nagoya U.)
report on behalf of the MAXI team:

At 2017-05-11T06:00 UT, the MAXI/GSC detected an uncatalogued X-ray
transient source.
The position reported to the MAXI new-transient mailing list was not accurate
due to an error of attitude determination.
With the corrected attitude information, we update the source
position assuming a constant source flux over the scan transit to be

 (R.A., Dec) = (300.633 deg, 33.315 deg) = (20 02 31, +33 18 53) (J2000)

with a statistical 90% C.L. elliptical error region
with long and short radii of 0.29 deg and 0.25 deg, respectively.
The roll angle of long axis from the north direction is 170.0 deg counterclockwise.
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).

The position and the time of the burst are consistent with a burst detected
by Fermi/GBM (trigger #516175156). Thus, we consider this event to be a GRB.
According to a quick-look light curve of Fermi/GBM, MAXI/GSC observed a tail 
part of the GRB.

The averaged X-ray flux was 228 +- 35 mCrab (4-10 keV). 
There were no significant excess fluxes at the previous
and followed scan transits at 2017/05/11 04:27 UT and 07:33 UT, 
respectively, with an upper limit of 20 mCrab for each.


GRB_name: GRB170522A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21138
SUBJECT: IPN Triangulation of GRB 170522A
DATE:    17/05/25 10:46:13 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,

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

and

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

The long duration GRB 170522A
(Fermi-GBM detection: Stanbro and Meegan, GCN Circ. 21126;
Fermi-LAT detection: Arimoto and Racusin, GCN Circ. 21127;
Konus-Wind observation: Frederiks et al., GCN Circ. 21129)
was detected by Fermi (GBM trigger 517160740), Konus-Wind,
INTEGRAL (SPI-ACS), Mars-Odyssey (HEND), and Swift (BAT),
at about 56735 s UT (15:45:35).
The burst was outside the coded field of view of the BAT.

We have triangulated it to a GBM-HEND annulus centered at 
RA(2000)=80.195 deg (05h 20m 47s) Dec(2000)=+23.945 deg (+23d 56' 40"), 
whose radius is 53.106 +/- 0.070 deg (3 sigma).

The LAT position reported by Arimoto and Racusin (GCN Circ. 21127)
is consistent with the annulus. The annulus combined with
the LAT (90 % containment, statistical-only) error circle
gives the following error box:
---------------------------------------------
  RA(2000), deg  Dec(2000), deg
---------------------------------------------
Center:
     139.1949    +25.6971
Corners:
     139.1335    +25.7084
     139.2170    +25.5157
     139.2562    +25.6856
     139.2950    +25.8556
---------------------------------------------
The error box area is 101.5 sq. arcmin
(a factor of 4 smaller that that of LAT error circle).

This box may be improved.

None of the Swift-XRT sources reported by Mingo et al. (GCN Circ. 21133)
are consistent with the box, and only Source 1 is consistent
with the annulus.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB170522_T56735/IPN


GRB_name: GRB170524A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21139
SUBJECT: GRB 170524A: Swift-XRT refined Analysis
DATE:    17/05/25 10:53:11 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), P. D'Avanzo
(INAF-OAB), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), B. Sbarufatti
(INAF-OAB/PSU), D.N. Burrows (PSU), A. Cholden-Brown (PSU), S.L. Gibson
(U. Leicester) and J.G. Gropp report on behalf of the Swift-XRT team:

We have analysed 9.9 ks of XRT data for GRB 170524A (Gropp et al. GCN
Circ. 21135), from 69 s to 46.6 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. 21136). There is
evidence that the source may be fading, however we cannot constrain the
decay at the current time

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00754322.

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


GRB_name: GRB170524A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21140
SUBJECT: GRB 170524A: D50 optical observation and limit
DATE:    17/05/25 10:57:36 GMT
FROM:    Martin Jelinek at Astro.Inst-AVCR,Ondrejov  <martin.jelinek@asu.cas.cz>

Jan Å trobl, RenÃ© Hudec and Martin JelÃ­nek (ASÃš CAS, OndÅ™ejov, CZ)

We observed the location of the recently discovered GRB 170524A (Gropp et
al., GCNC 21135) with the 0.5m robotic telescope D50 located in OndÅ™ejov,
Czech Republic. The unfiltered CCD observations started 4 hours after the
trigger, once the position got available above local horizon, and had to be
interrupted after 20 minutes because of passing clouds. The sum of all
images obtained has a mean exposure time 00:02:23UT, i.e. 4.22h after the
GRB, and a limiting magnitude of R>20.2. No object was detected within the
XRT errorbox (Evans et al., GCNC 21136).


GRB_name: GRB170524A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21141
SUBJECT: GRB 170524A: Swift/UVOT Upper Limits
DATE:    17/05/25 12:37:02 GMT
FROM:    Sam Emery at MSSL-UCL  <samuel.emery.15@ucl.ac.uk>

S.W.K. Emery (UCL-MSSL) and J.G. Gropp (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 170524A
67 s after the BAT trigger (Gropp et al., GCN Circ. 21135).
No optical afterglow consistent with the XRT position
(Evans et al. GCN Circ. 21136)
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          217          147         >20.4
u_FC               280          529          246         >19.5
white               67         1007          334         >20.6
v                  610         1058           58         >17.9
b                  535         1157           58         >18.7
u                  280         1132          285         >19.5
w1                 660         1107           58         >18.3
m2                1063         1082           19         >17.3
w2                 586         1033           58         >18.6

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 2.82 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB170524B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21142
SUBJECT: GRB 170524B: Swift detection of a burst 
DATE:    17/05/25 18:29:03 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

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

At 10:40:40 UT on 2017-05-24, the Swift Burst Alert Telescope (BAT) triggered on
GRB 170524B (trigger=754265).  However, on-board analysis was truncated by
a pre-planned slew to a scheduled target.  Subsequent ground analysis
using data from T+2 to T+101 s finds the source at a location of
RA, Dec 90.864, -17.086, which is
RA(J2000)  =  06h 03m 27s
Dec(J2000) = -17d 05' 11"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty).

The BAT light curve shows a complex structure about 50 seconds long.
The raw peak count rate was ~18000 counts/sec (15-350 keV), at ~7 sec after
the trigger. T90 (15-350 keV) estimated using the raw light curve is 46.4 +- 1.6 sec
(estimated error including systematics).

The time-averaged spectrum from T+1.8 to T+49.6 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.15 +- 0.06.  The fluence in the 15-150 keV band is (6.6 +/- 0.2) x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+6.70 sec in the 15-150 keV band
is 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

This event was also detected by CALET, KONUS-Wind, and INTEGRAL SPI ACS.

A Swift Target of Opportunity observation has been requested.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/00753445006/BA/


GRB_name: GRB170524A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21143
SUBJECT: GRB 170524A: Swift-BAT refined analysis 
DATE:    17/05/25 18:53:59 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), J.G. Gropp (PSU),
H. A. Krimm (NSF/USRA), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):

Using the data set from T-61 to T+242 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 170524A (trigger #754322)
(Gropp et al., GCN Circ. 21135).  The BAT ground-calculated position is
RA, Dec = 319.488, 48.603 deg which is
  RA(J2000)  =  21h 17m 57.2s
  Dec(J2000) = +48d 36' 12.5"
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 96%.

The mask-weighted light curve shows a double peaked structure
with the first pulse from ~T0 to ~T+0.05, and second pulse from ~T+0.05 to ~T+0.1.
T90 (15-350 keV) is 0.10 +- 0.02 sec (estimated error including systematics).

The time-averaged spectrum from T+0.00 to T+0.12 sec fit by a simple
power-law model shows the power law index of 1.07 +- 0.24 (chi squared 47.68 for 57 d.o.f.).
The fluence in the 15-150 keV band is 3.7 +- 0.6 x 10^-8 erg/cm2.
The 1-sec peak photon flux measured from T-0.44 sec in the 15-150 keV band
is 0.5 +- 0.1 ph/cm2/sec.

A single blackbody fit to the time-averaged spectrum shows the blackbody
temperature of 21.09 +- 3.99 keV (chi squared 51.91 for 57 d.o.f.).
A thermal bremsstrahlung model fit shows the temperature of 199.36 +- -80.44 keV
(chi squared 57.87 for 57 d.o.f.).  A double blackbody fit shows the lower temperature
of 5.84 (error not unconstrained) keV and the higher temperature of 25.96 +15.56 keV
(chi squared 45.99 for 55 d.o.f.).  All the quoted errors are at the 90% confidence level.

The photon index of ~ 1 using the simple power-law model is consistent with those from
the BAT-detected short GRBs (Lien & Sakamoto et al. 2016), and harder than
the spectra of many BAT-detected SGRs, which have photon index ~ 3.
In addition, the double-peaked structure seen in this burst is not commonly observed in
the BAT light curves of SGRs (with time bins >= 2 ms).

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/754322/BA/


GRB_name: GRB170524B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21144
SUBJECT: GRB 170524B: Swift ToO observations
DATE:    17/05/25 19:51:17 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift has initiated a ToO observation of the Swift/BAT GRB 170524B. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020775

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

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

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


GRB_name: GRB170524A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21145
SUBJECT: GRB 170524A: TSHAO and CrAO optical observations
DATE:    17/05/25 20:28:02 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI), S. Nazarov (CrAO), 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 the Swift GRB 170524A (trigger=754322) (Gropp 
et al., GCN 21135)  with Zeiss-1000 (East) of Tien Shan Astronomical 
Observatory and AZT-8 telescope of CrAO. We obtained several images in R 
filter. The TSHAO observations started on 2017-05-24 (UT) 20:31:45 under 
not optimal weather conditions.  Observations in CrAO started on 
2017-05-25 (UT) 00:18:50. Within enhanced XRT position (Evans et al. GCN 
21136)  we did not detect any  optical source in the first epoch. In the 
second epoch (CrAO observation) we detected an object which is on the 
edge of the  enhanced XRT position. The object has coordinates (J2000) 
21:17:56.30 +48:36:27.9 with uncertainties of about 1 arcsec in each 
coordinate and brightness of R=20.10 +/- 0.15 at 0.1992 days after the 
Swift trigger. For now we can not say anything about the object 
variability. However the object is barely visible in DSS2 (Red).
The preliminary results of field photometry are as follows

Date       UT start   t-T0   Filter  Exp.      UL(3 sigma)
                       (mid, days)    (s)

2017-05-24 20:31:45 0.06857  R       46*120    20.3
2017-05-25 00:18:50 0.19920  R       10*180    21.5

Photometry is based on nearby USNO-B1.0 stars

USNO-B1.0_id    R2

1386-0392957 16.69

1385-0394718 17.29

1386-0392907 17.11


The finding chart of the object can be found at
http://grb.rssi.ru/GRB170524A/GRB170524A_CrAO_170524.png


GRB_name: GRB170511A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21146
SUBJECT: GRB 170511A CALET Gamma-Ray Burst Monitor detection
DATE:    17/05/26 08:50:40 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

K. Yamaoka (Nagoya U), A. Yoshida, T. Sakamoto, Y. Kawakubo,
M. Moriyama, Y. Yamada, A. Tezuka, S. Matsukawa (AGU), S. Nakahira (RIKEN),
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), A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long-duration GRB 170511A (Takao et al., GCN Circ. 21137;
Fermi-GBM trigger #516175156) was detected by the CALET
Gamma-ray Burst Monitor (CGBM).  The burst signal was only seen
by the SGM instrument.  Since the detection significance is less than
7 sigma in the CGBM data, no on-board trigger occurred for this event.

The light curve of the SGM shows two separated peaks.  The initial peak
starts at T+25 sec, peaks at T+28 sec and ends at T+33 sec (T is the trigger
time of Fermi-GBM).  The second peak starts at T+35 sec, peaks at T+38 sec
and ends at T+40 sec.  The T90 duration measured by the SGM data is
12.5 +- 1.0 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1178517128/

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


GRB_name: GRB170524B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21147
SUBJECT: GRB 170524B: MASTER-OAFA  observations 
DATE:    17/05/26 09:42:12 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),
National University of San Juan, Argentina

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

V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, D.Kuvshinov, A.V.Krylov,
I.Gorbunov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University, Sternberg Astronomical Institut of MSU

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

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

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

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

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


MASTER   robotic telescope (6 square degrees) 
located in OAFA was pointed to the  GRB170525B (Barthelmy et al., GCN 
#21142) 15191 sec after notice 
time and 43294 sec after trigger time at 2017-05-25 22:42:14 UT. On our 
first (180s exposure)  set we haven't found optical transient  within 
Master error-box (ra=90.8625 dec=-17.0861 r=0.1).

The 5-sigma upper limit has been about 18.3 mag

There is no OT at added images brighter 19.9 at Swift XRT position 
(Barthelmy et al., GCN #21142; Evans, GCN #21144 ).

The observations made on zenit distance = 59 degrees, galaxy latitude b = 
-18 degree.
The moon ( 0 % bright part) below the horizon (The altitude of the Moon is 
-8 degree ).
Observations started at twilight. The sun  altitude  is -12.7 degree.
The object can be observed till 2017-05-26 01:12:20

The message may be cited.


GRB_name: GRB170524B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21148
SUBJECT: Konus-Wind observation of GRB 170524B
DATE:    17/05/26 11:33:22 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 long GRB 170524B (Swift/BAT detection: Barthelmy et al., GCN 21142)
triggered Konus-Wind at T0=38438.475 s UT (10:40:38.475).

The KW light curve shows a multi-peaked emission with a total duration
of ~24 s.
The emission is seen up to ~10 MeV.

As observed by Konus-Wind, the burst had a fluence of
(5.7 Â± 0.4)x10^-5 erg/cm2 and a 64-ms peak energy flux,
measured from T0+1.644, of (1.44 Â± 0.10)x10^-5 erg/cm2
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+21.760 s)
is best fit in the 20 keV - 15 MeV range by a cutoff power-law
(CPL) function with the following model parameters:
the photon index alpha = -0.85(-0.06,+0.06),
and the peak energy Ep = 766(-74,+87) keV,
chi2 = 93/98 dof.
Fitting this spectrum with the GRB (Band) function yields
the same alpha and Ep, and an upper limit on beta of -2.5,
chi2 = 93/97 dof.

The spectrum near the peak count rate (measured from T0 to T0+5.376 s)
is best fit in the 20 keV - 15 MeV range by the CPL function
with the following model parameters:
the photon index alpha = -0.72(-0.06,+0.06),
and the peak energy Ep = 860(-73,+83) keV,
chi2 = 111/98 dof.
Fitting this spectrum with the GRB (Band) function yields
the same alpha and Ep, and an upper limit on beta of -2.7,
chi2 = 110/97 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB170524_T38438/

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


GRB_name: GRB170526A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21149
SUBJECT: GRB 170526A: Swift detection of a burst
DATE:    17/05/26 13:51:22 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

B. Sbarufatti (INAF-OAB/PSU), S. D. Barthelmy (GSFC),
S. B. Cenko (GSFC), C. Gronwall (PSU), J. A. Kennea (PSU),
N. P. M. Kuin (UCL-MSSL), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL)
and M. H. Siegel (PSU) report on behalf of the Swift Team:

At 13:35:08 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 170526A (trigger=754549).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 4.708, +1.240 which is 
   RA(J2000)  =  00h 18m 50s
   Dec(J2000) = +01d 14' 22"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a single peak
with a duration of about 8 sec.  The peak count rate
was ~1200 counts/sec (15-350 keV), at ~5 sec after the trigger. 

The XRT began observing the field at 13:37:13.2 UT, 124.3 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 4.7074, 1.2773 which is
equivalent to:
   RA(J2000)  = 00h 18m 49.79s
   Dec(J2000) = +01d 16' 38.1"
with an uncertainty of 4.9 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.  We cannot determine whether the source is
fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 3.16
x 10^20 cm^-2 (Willingale et al. 2013). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 127 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 0.03. 

Burst Advocate for this burst is B. Sbarufatti (boris.sbarufatti 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: GRB170524B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21150
SUBJECT: GRB 170524B: Swift-XRT observations
DATE:    17/05/26 15:05:52 GMT
FROM:    Aaron Cholden-Brown at PSU/Swift  <aaronb@swift.psu.edu>

A. Cholden-Brown (PSU), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A.
Melandri (INAF-OAB), D.N. Burrows (PSU), S. J. LaPorte (PSU), S.L.
Gibson (U. Leicester), J.P. Osborne (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
Swift/BAT-detected burst GRB 170524B (Barthelmy et al. GCN Circ.
21142), collecting 2.1 ks of Photon Counting (PC) mode data between
T0+119.5 ks and T0+126.8 ks. 

One uncatalogued X-ray source has been detected consistent with being
within 296 arcsec of the Swift/BAT position, it is below the RASS limit
and shows no definitive signs of fading. Therefore, at the present time
we cannot confirm this as the afterglow. Details of this source are
given below:

Source 1:
  RA (J2000):  90.86806  =  06:03:28.33
  Dec (J2000): -17.08282  =  -17:04:58.2
  Error: 2.3 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: 0.0240 +/- 0.0038 ct s^-1   
  Distance: 18 arcsec from Swift/BAT position.
  Flux: (7.1 +/- 1.1)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
http://www.swift.ac.uk/ToO_GRBs/00020775.

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


GRB_name: GRB170526A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21151
SUBJECT: GRB 170526A: Enhanced Swift-XRT position
DATE:    17/05/26 16:27:05 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 350 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 170526A, 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 = 4.70720, +1.27700 which is equivalent
to:

RA (J2000): 00h 18m 49.73s
Dec (J2000): +01d 16' 37.2"

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: GRB170524A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21152
SUBJECT: GRB 170524A: RATIR Optical and NIR Observations
DATE:    17/05/26 19:08:59 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), JesÃºs
GonzÃ¡lez (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM), Harvey Moseley (GSFC), John
Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:

We observed the field of GRB 170524A (Gropp, et al., GCN 21135) 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 2017/05 25.40 to 2017/05 25.46 UTC (13.79 to
15.29 hours after the BAT trigger), obtaining a total of 1.06 hours
exposure in the r and i bands and 0.36 hours exposure in the Z, Y, J, and H
bands.

We again observed from 2017/05 26.32 to 2017/05 26.47 UTC (35.77 to 39.48
hours after the BAT trigger), obtaining a total of 2.42 hours exposure in
the r and i bands and 1.01 hours exposure in the Z, Y, J, and H bands.

For a source within the Swift-XRT error circle (Evans, et al., GCN 21136),
in comparison with the USNO-B1 and 2MASS catalogs, we obtain the following
upper limits (3-sigma):

     5/25      5/26
  r  > 24.45   > 25.66
  i  > 23.25   > 24.52
  Z  > 21.72   > 23.00
  Y  > 21.26   > 22.57
  J  > 18.16   > 21.25
  H  > 17.83   > 21.50

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: GRB170526A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21154
SUBJECT: GRB 170526A: Swift-XRT refined Analysis
DATE:    17/05/27 04:29:59 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB),
A. Cholden-Brown (PSU), S. J. LaPorte (PSU), J.A. Kennea (PSU), S.L.
Gibson (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester) and B. Sbarufatti report on behalf of the Swift-XRT team:

We have analysed 6.5 ks of XRT data for GRB 170526A (Sbarufatti et al.
GCN Circ. 21149), from 132 s to 46.4 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. 21151).

The light curve can be modelled with a power-law decay with a decay
index of alpha=0.87 (+0.14, -0.12).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.8 (+/-0.5). The
best-fitting absorption column is  1.9 (+2.3, -1.6) x 10^21 cm^-2,
consistent with the Galactic value of 3.2 x 10^20 cm^-2 (Willingale et
al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux
conversion factor deduced from this spectrum  is 4.0 x 10^-11 (5.0 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.9 (+2.3, -1.6) x 10^21 cm^-2
Galactic foreground: 3.2 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.8 (+/-0.5)

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 1.0 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.0 x
10^-14 (5.1 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/00754549.

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


GRB_name: GRB170526A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21155
SUBJECT: GRB 170526A: Swift/UVOT Upper Limits 
DATE:    17/05/27 13:28:48 GMT
FROM:    Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>

S. R. Oates (Uni. of Warwick) and B. Sbarufatti (INAF-OAB/PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 170526A
128 s after the BAT trigger (Sbarufatti et al., GCN Circ. 21149).
No optical afterglow consistent with the XRT position
(Goad et al. GCN Circ. 21151) 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           128          278          147         >19.9
white              128         4127          344         >20.4
v                4338         4537          197         >18.5
b                 3722         5197          235         >19.7
u                  286         5152          404         >19.4
w1                4748         4947          196         >19.1
m2                4542         4742          197         >19.3
w2                4133         4333          197         >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: GRB170526A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21156
SUBJECT: GRB 170526A, Swift-BAT refined analysis
DATE:    17/05/27 18:52:59 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL),
T. Sakamoto (AGU), B. Sbarufatti (INAF-OAB/PSU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):

Using the data set from T-327 to T+1275 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 170526A (trigger #754549)
(Sbarufatti et al., GCN Circ. 21149).  The BAT ground-calculated position is
RA, Dec = 4.723, 1.277 deg which is
  RA(J2000)  =  00h 18m 53.6s
  Dec(J2000) = +01d 16' 35.7"
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 94%.

The mask-weighted light curve shows a weak pulse structure that starts
at ~T0, peaks at ~ T+1 s, and ends at ~ T+10 s. T90 (15-350 keV) is 7.9 +- 1.6 sec
(estimated error including systematics).

The time-averaged spectrum from T+1.1 to T+10.0 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.25 +- 0.42.  The fluence in the 15-150 keV band is 1.6 +- 0.4 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+1.10 sec in the 15-150 keV band
is 0.3 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/754549/BA/


GRB_name: GRB170527A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21157
SUBJECT: GRB 170527A: Fermi GBM detection
DATE:    17/05/27 20:09:57 GMT
FROM:    C. Michelle Hui at MSFC/Fermi-GBM  <c.m.hui@nasa.gov>

M. Stanbro (UAH), C. M. Hui (NASA/MSFC), C. Meegan (UAH)
and A. von Kienlin (MPE) report on behalf of the Fermi GBM Team:

At 11:31:02.37 UT on 27 May 2017, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 170527A (trigger 517577467 / 170527480).

The on-ground calculated location, using the GBM trigger
data, is RA = 195.19 , DEC = +0.94  (J2000 degrees,
equivalent to 13h 00m, +0d 54.0'), with an uncertainty
of 1.00 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 is 37.00 degrees.

The GBM light curve shows a sharp peak with multiple sub-structures
with a duration (T90) of about 49.2 s (50-300 keV).
The time-averaged spectrum from T0+1.1 s to T0+50.3 s is 
adequately fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.03 +/- 0.01 and
the cutoff energy, parameterized as Epeak, is 1001.00 +/- 33.50 keV

The event fluence (10-1000 keV) in this time interval is
(8.430 +/- 0.003)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.8 s in the 10-1000 keV band is 
22.19 +/- 0.36 ph/s/cm^2.

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


GRB_name: GRB170511A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21161
SUBJECT: GRB 170511A: Fermi GBM observation
DATE:    17/05/29 14:00:55 GMT
FROM:    Elisabetta Bissaldi at U.Innsbruk/IAPP  <Elisabetta.Bissaldi@uibk.ac.at>

E. Bissaldi (Politecnico & INFN Bari), O.J. Roberts (USRA/NASA)
and C. Meegan (UAH) report on behalf of the Fermi GBM Team:


"At 05:59:11.92 UT on 11 May 2017, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 170511A (trigger 516175156 / 170511249),
which was also detected by MAXI/GSC (Takao et al. 2017, GCN 21137)
and by the CALET GBM (Yamaoka et al. 2017, GCN 21146).
The GBM on-ground location is consistent with the MAXI position.
The angle from the Fermi LAT boresight at the GBM trigger time is 85 degrees.

The GBM light curve consists of multiple peaks
with a duration (T90) of about 40 s (50-300 keV).
The time-averaged spectrum from T0 to T0+40 s is
best fit by a Band function with Epeak = 82 +/- 3 keV,
alpha = -0.90 +/- 0.03, and beta = -2.41 +/- 0.05.
The event fluence (10-1000 keV) in this time interval is
(2.80 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+34.5 s in the 10-1000 keV bandbis 30.1 +/- 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: GRB170519A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21162
SUBJECT: GRB 170519A: ISON/Multa optical observations
DATE:    17/05/29 18:41:18 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI), A. Krylov (KIAM), Yu. Krylova (KIAM), S. Schmalz 
(KIAM), A. Volnova (IKI), A. Pozanenko (IKI) report on behalf of larger 
GRB follow-up collaboration:

We observed the field of GRB 170519A (Ukwatta et al., GCN 21106) with 
22cm SSS-220 telescope of ISON/Multa observatory(* starting on May 19 
(UT) 16:02:54. We took 120 unfiltered frames with 60 s exposure. The 
optical transient (Ukwatta et al., GCN 21106; Izzo, et al., GCN 21108) 
is clearly detected in a combined image.

Preliminary photometry of the combined image is following

Date        UT start  t-T0     Filter  Exp.   OT     err   UL
                       (mid, days)      (s)               (3sigma)
2017-05-19  16:02:54  0.53936  CR      120*60 18.92  0.28 19.0 

The photometry is based on nearby SDSS stars:

SDSS-DR9_id         R(Lupton)
J105316.02+252545.1 16.75
J105332.97+252127.3 16.22
J105336.13+251707.2 15.46
J105322.03+251651.0 15.91
J105339.27+251620.6 16.66
J105338.87+252621.2 16.00

*) The ISON/Multa observatory is located in Altai, N 50d 10â€² 07â€³ E 85d 
57â€² 25â€³. The SSS-220  telescope (22 cm, f/2.3) is equipped with CCD 
camera ML 11002.


GRB_name: GRB170511A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21163
SUBJECT: GRB 170511A: AstroSat CZTI detection
DATE:    17/05/30 09:20:19 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

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

Analysis of Astrosat data showed the CZTI detection of a bright GRB 170511A which was also detected by MAXI/GSC (Takao et al., GCN 21137), CALET GBM (Yamaoka et al., GCN 21146) and Fermi GBM (E. Bissaldi et al., GCN 21161).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks emission with the strongest peak at 05:59:40.920 UT, ~30 s after the Fermi Trigger. The measured peak count rate is 515.9 cts/s above the background in combined data of four quadrants, with a total of 5191 cts. The local mean background count rate was 373 cts/s. Using cumulative rates, we measure a T90 of 36.6 s.

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: GRB170527A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21164
SUBJECT: IPN Triangulation of GRB 170527A
DATE:    17/05/30 15:11:47 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, 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 170527A (Stanbro et al.,GCN 21157)
was detected by Fermi(GBM), Konus-Wind, and
Mars-Odyssey(HEND), at about 41467 s UT (11:31:07).

We have triangulated it to a preliminary, 3 sigma error box whose
coordinates are:
 ---------------------------------------------
  RA(2000), deg       Dec(2000), deg
 ---------------------------------------------
 Center:
   192.3245             -1.4883
 Corners:
   192.3882             -1.5179
   197.2538             +8.1347
   196.7137             +7.4412
   192.2608             -1.4588
   188.2675            -10.5805
   188.0687            -11.4344
 ---------------------------------------------
The error box area is 2.9 sq. deg, and its maximum
dimension is 21.6 deg (the minimum one is 8.4 arcmin).
The Sun distance was about 125 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB170527_T41466/IPN/

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


GRB_name: GRB170529A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21165
SUBJECT: IPN Triangulation of GRB 170529A (long)
DATE:    17/05/30 15:36:18 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,

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

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

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

A long-duration, GRB 170529A has been detected by
Konus-Wind, Mars-Odyssey (HEND), INTEGRAL (SPI-ACS), and Swift (BAT),
so far, at about 25538 s UT (07:05:38).
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:
   164.499 (10h 58m 00s) -17.934 (-17d 56' 01")
  Corners:
   163.130 (10h 52m 31s) -20.393 (-20d 23' 34")
   163.049 (10h 52m 12s) -20.800 (-20d 48' 01")
   165.951 (11h 03m 48s) -15.216 (-15d 12' 59")
   166.065 (11h 04m 15s) -14.719 (-14d 43' 08")
  ---------------------------------------------
The error box area is 2644 sq. arcmin, and its maximum
dimension is 6.7 deg (the minimum one is 7.1 arcmin).
The Sun distance was 103 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB170529_T25541/IPN/

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


GRB_name: GRB170527A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21166
SUBJECT: Konus-Wind observation of GRB 170527A
DATE:    17/05/30 16:11:27 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 long GRB 170527A (IPN localization: Hurley et al., GCN 21164)
triggered Konus-Wind at T0=41466.714 s UT (11:31:06.714).

The KW light curve shows a multi-peaked emission with a total duration
of ~57 s. The emission is seen up to ~5 MeV.

As observed by Konus-Wind, the burst had a fluence of
(8.9 Â± 0.6)x10^-5 erg/cm2 and a 64-ms peak energy flux,
measured from T0+0.640, of (1.79 Â± 0.13)x10^-5 erg/cm2
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+48.128 s)
is best fit in the 20 keV - 15 MeV range by a cutoff power-law
(CPL) function with the following model parameters:
the photon index alpha = -0.71(-0.09,+0.09),
and the peak energy Ep = 571(-47,+55) keV,
chi2 = 103/98 dof.
Fitting this spectrum with the GRB (Band) function yields
the same alpha and Ep and an upper limit on beta of -2.5,
chi2 = 102/97 dof.

The spectrum near the peak count rate (measured from T0 to T0+7.168 s)
is best fit in the 20 keV - 15 MeV range by the CPL function
with the following model parameters:
the photon index alpha = -0.23(-0.10,+0.10),
and the peak energy Ep = 714(-44,+48) keV,
chi2 = 113/98 dof.
Fitting this spectrum with the GRB (Band) function yields
the same alpha and Ep, and an upper limit on beta of -3.9,
chi2 = 113/97 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB170527_T41466/

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


GRB_name: GRB170529A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21167
SUBJECT: Konus-Wind observation of GRB 170529A
DATE:    17/05/30 16:22:19 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 GRB 170529A
(IPN triangulation: Hurley et al., GCN 21165)
triggered Konus-Wind at T0=25541.567 s UT (07:05:41.567).

The burst light curve shows two separate multipeaked episodes: the first
from ~T0-6 s to ~T0+52 s and the second weaker/softer
from ~T0+176 s to ~T0+220 s. The total duration of the burst is ~226 s.
The emission is seen up to 20 MeV.

As observed by Konus-Wind, the burst
had a fluence of 1.73(-0.40,+0.62)x10^-4 erg/cm2,
and a 64-ms peak flux, measured from T0+7.504 s,
of 1.54(-0.27,+0.28)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+222.464 s)
is best fit in the 20 keV - 20 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.96(-0.16,+0.46),
the high energy photon index beta = -2.23(-1.36,+0.41),
the peak energy Ep = 422(-188,+142) keV
(chi2 = 89/98 dof).

The spectrum near the maximum count rate
(measured from T0+6.656 to T0+11.008 s)
is best fit in the 20 keV - 20 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.49(-0.10,+0.11),
the high energy photon index beta = -2.41(-0.28,+0.18),
the peak energy Ep = 486(-54,+59) keV
(chi2 = 75/87 dof).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB170529_T25541/

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


GRB_name: GRB170524B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21168
SUBJECT: GRB 170524B: Swift-UVOT/XRT Confirmation of Afterglow
DATE:    17/05/30 19:07:35 GMT
FROM:    Jeffrey Gropp at PSU  <jdg44@psu.edu>

J.D. Gropp (PSU), M.H. Siegel (PSU), J.A. Kennea (PSU), A.
Cholden-Brown (PSU) reporting on behalf of the Swift team.


The Swift-UVOT and XRT began settled observations of the field of GRB
170524B 120 ks after the

BAT trigger (Barthelmy et al., GCN Circ. 21142). A fading source
consistent with the XRT position

is detected in the UVOT exposures.

Swift-XRT performed follow-up observations of the
Swift/BAT-detected burst GRB 170524B (Barthelmy et al. GCN Circ.21142),
collecting an additional 3ks (5.1 total) of Photon Counting (PC) mode data.

One uncatalogued X-ray source has been detected consistent with being
within 296 arcsec of the Swift/BAT position. There is also evidence of fading,

which is confirmed with UVOT analysis.

XRT light curve can be modeled with a power-law decay with a decay
index alpha = 1.3


The preliminary UVOT position is:
    RA  (J2000) =  06:03:28.49 =  90.86872 (deg.)
    Dec (J2000) = -17:04:58.7  = -17.08297 (deg.)
with an estimated uncertainty of 0.4 arc sec. (radius, 90% confidence).

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

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

white            120431        126833        1297          19.89+-0.08
white            274703        286595        2027          21.11+-0.23

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.19 in the direction of the burst.

The decay inferred from the UVOT white data suggests a slope of
approximately -1.3.

This circular is an official product of the Swift team.


GRB_name: GRB170519A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21169
SUBJECT: GRB 170519A: CrAO optical observations
DATE:    17/05/30 20:33:55 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

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

We observed the field of the GRB 170519A (Ukwatta et al., GCN 21106)
with AZT-11 telescope of CrAO observatory starting on May 19 (UT)
19:07:44, and with Zeiss-1000/Koshka telescope of Simeiz branch of CrAO
observatory starting on May 19 (UT) 19:28:57. We took several images in 
filter R with exposures of 180 s. We clearly detect the afterglow 
(Ukwatta et al., GCN 21106; Izzo et al., GCN 21108) in combined images.

Preliminary photometry of the combined images is following

UT start    t-T0   Filter       Exp.     OT      err    UL    Telescope
            (mid, days)       (s)                       (3sigma)


19:07:44   0.58810 R 6*180    19.17   0.11   20.9  AZT-11
19:26:08   0.59878 R 4*180    19.23   0.12   20.7  AZT-11
19:41:28   0.61473 R 9*180    19.58   0.12   21.1  AZT-11
19:28:57   0.59751 R 1*180    19.05   0.10   20.4  Zeiss-1000
19:31:58   0.60066 R 2*180    19.12   0.10   21.1  Zeiss-1000
19:38:02   0.60592 R 3*180    19.52   0.14   20.3  Zeiss-1000
19:47:08   0.61224 R 3*180    19.52   0.16   20.3  Zeiss-1000
19:56:13   0.62065 R 5*180    19.64   0.14   21.3  Zeiss-1000

The photometry is based on nearby SDSS stars:

SDSS-DR9_id     R(Lupton)
J105339.53+252259.9 17.32
J105332.97+252127.3 16.22  
J105348.21+252041.2 17.03   
J105341.14+252534.0 16.18    
J105353.70+252400.0 15.30


GRB_name: GRB170531A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21170
SUBJECT: GRB 170531A: Swift detection of a burst
DATE:    17/05/31 20:33:44 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

P.A. Evans (U Leicester), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF/USRA), N. P. M. Kuin (UCL-MSSL),
A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester), D. M. Palmer (LANL), M. H. Siegel (PSU) and
T. N. Ukwatta (LANL) report on behalf of the Swift Team:

At 20:07:32 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 170531A (trigger=755343).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 121.261, -14.033 which is 
   RA(J2000)  =  08h 05m 03s
   Dec(J2000) = -14d 01' 57"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  As is typical for image triggers, there is nothing
significant in the real-time light curve.  We note that this trigger occurred
while coming out of the SAA. 

The XRT began observing the field at 20:09:35.5 UT, 122.6 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 121.25380, -14.02292 which
is equivalent to:
   RA(J2000)  = 08h 05m 00.91s
   Dec(J2000) = -14d 01' 22.5"
with an uncertainty of 4.5 arcseconds (radius, 90% containment). This
location is 44 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 2.92e-10 erg cm^-2 s^-1 (0.2-10
keV). 

No UVOT data are available at this time. 

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: GRB170531B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21171
SUBJECT: GRB 170531B: Swift detection of a burst
DATE:    17/05/31 22:23:52 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

P.A. Evans (U Leicester), A. P. Beardmore (U Leicester),
D. N. Burrows (PSU), A. Cholden-Brown (PSU), A. Y. Lien (GSFC/UMBC),
K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of
the Swift Team:

At 22:02:09 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 170531B (trigger=755354).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 286.895, -16.426 which is 
   RA(J2000) = 19h 07m 35s
   Dec(J2000) = -16d 25' 34"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a complex
structure with a duration of at least 50 sec.  The peak count rate
was ~2000 counts/sec (15-350 keV), at ~6 sec after the trigger. 

The XRT began observing the field at 22:04:30.1 UT, 140.9 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source with an enhanced position: RA, Dec 286.8835,
-16.4196 which is equivalent to:
   RA(J2000)  = 19h 07m 32.03s
   Dec(J2000) = -16d 25' 10.4"
with an uncertainty of 2.3 arcseconds (radius, 90% containment). This
location is 45 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 1.41
x 10^21 cm^-2 (Willingale et al. 2013). 

The initial flux in the 2.5 s image was 2.73e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 152 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 0.19. 

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: GRB170531A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21172
SUBJECT: GRB 170531A: Swift/UVOT Observations
DATE:    17/05/31 23:04:56 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@swift.psu.edu>

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

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 3522 seconds after the BAT trigger. No credible afterglow candidate
has been found in the initial data products. The 2.7'x2.7' sub-image covers
100% of the XRT error circle. The typical 3-sigma upper limit has been about
19.6 mag. The coverage of the XRT error circle by the 8'x8' region for the list
of sources generated on-board is uncertain because the large number of sources
filled the available telemetry. The list of sources is typically complete to
about 18 mag. No correction has been made for the expected extinction
corresponding to E(B-V) of 0.09. 


GRB_name: GRB170531B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21173
SUBJECT: GRB 170531B: MASTER Net  OT detection 
DATE:    17/05/31 23:19:01 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, N.Tyurina, E.Gorbovskoy, D.Kuvshinov, A.V.Krylov,
I.Gorbunov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University, Sternberg Astronomical Institut of MSU

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

N.M.Budnev, O.Gres, O. Ershova 
Irkutsk State University

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

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

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

R.Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA),
National University of San Juan, Argentina

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


MASTER-Kislovodsk robotic telescope (2x4 square degrees, MASTER-Net: 
http://observ.pereplet.ru)  was pointed to the  GRB170531B (Evans et al.,
GCN #21171)  12 sec after notice time and 452 sec after trigger 
time on 2017-05-31 22:09:44 UT.
There is marginally seen optical transient at the position 19h 07m 32.03s 
-16d 25' 10.4" with m_OT~19.0+-0.5

The 5-sigma upper limit is about 18.5mag
The message may be cited.


====================================================================



The observations made on zenit distance = 64 degrees, galaxy latitude b = -11 degree.
The moon (44 % bright part) below the horizon (The Moon altitude is -6 degree).
The sun  altitude  is -22.7 degree.
The object can be observed till sunrise at 2017-06-01 01:30:50 .



The message may be cited.


GRB_name: GRB170531B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21174
SUBJECT: GRB 170531B:  CrAO confirmation of the afterglow
DATE:    17/06/01 00:11:21 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

A. Pozanenko (IKI), D. Chestnov (ISON), A. Novichonok (ISON), A. Mokhnatkin 
(ISON)   report on behalf of larger GRB follow-up collaboration:

We observed the field of the GRB 170531B (Evans et al.,GCN  21171) with 
with Zeiss-1000/Koshka telescope  starting on May 31 (UT) 22:32:32, i.e. ~30 
minutes after burst onset.  We took several images in  filter R with 
exposures of 180 s. Near the border of XRT error circle (Evans et al.,GCN 
21171)  we  detect the source in coordinates (J2000) 19:07:31.67 -16:25:09.3 
with uncertainity of 0.5 arcsec in both coordinates. The source is probably 
coincedent with the object reported by (Lipunov et al., GCN  21172). The 
source is fading from R=19.1 at (UT) 22:32:32 down to R=19.5 at  (UT) 
23:30:56. Most probably the source is an afterglow of  GRB 170531B. 


GRB_name: GRB170531B
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21175
SUBJECT: GRB 170531B: Enhanced Swift-XRT position
DATE:    17/06/01 00:59:47 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 1160 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 170531B, 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 = 286.88369, -16.41911 which is equivalent
to:

RA (J2000): 19h 07m 32.09s
Dec (J2000): -16d 25' 08.8"

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

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

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


GRB_name: GRB170531A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21176
SUBJECT: GRB 170531A: ePESSTO NTT observations
DATE:    17/06/01 01:29:05 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>

G. Pignata (Univ. Andres Bello), L. Wang (CASSACA), P. D'Avanzo (INAF-OAB), D. Malesani (Dark/NBI), L. Izzo (IAA-CSIC), S. Campana (INAF OAB), J. Anderson (ESO), R. Cartier (Southampton), L. Galbany (Univ. de Chile), C. Inserra (QUB), E. Kankare (QUB), K. Maguire (ESO), S. Smartt (QUB), K. W. Smith (QUB), M. Sullivan (Southampton), S. Valenti (UC Davis), O. Yaron (Weizmann), D. Young (QUB), I. Manulis (Weizmann)

We observed GRB 170531A (Evans et al., GCN 21170) under the extended Public ESO Spectroscopic Survey for Transient Objects (ePESSTO; see Smartt et al. 2015, A&A, 579, 40 http://www.pessto.org ). The observations were performed on the ESO New Technology Telescope at La Silla with the EFOSC2 instrument in imaging mode starting from 2017-05-31 at 23:12:07 UT (i.e. 3.1 hours from the burst).

We obtained two consecutive images each one lasting 150s with the r filter. No optical afterglow is detected in the coadded image within the XRT error circle (http://www.swift.ac.uk/xrt_positions/) down to a limiting magnitude of r > 23 (AB; 3sigma c.l.). The photometric calibration was carried out assuming r=17.07 (AB) for the star at RA(J2000), Dec(J2000) = 08:05:00.30, -14:01:21.3, as reported in the PANSTARRS catalogue. 


GRB_name: GRB170531B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21177
SUBJECT: GRB 170531B: Redshift from GTC/OSIRIS
DATE:    17/06/01 06:34:45 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 (IAA-CSIC), C.C. Thoene (IAA-CSIC), Z. Cano 
(IAA-CSIC), J.P.U. Fynbo (DARK/NBI), D. Garcia Alvarez 
(GTC, IAC), D. Perez Valladares (GTC), A. NuÃ±ez (GTC), M. Huertas (GTC)
report on behalf of a larger collaboration:

We observed the afterglow of GRB 170531B (Evans et al. GCN 
21171, Lipunov et al. GCN 21173, Pozanenko et al. GCN 21174) 
using OSIRIS at the 10.4 m GTC telescope in La Palma (Spain). 
Observation consisted in 3x900s exposures using the R1000B 
grism, covering the range between 3700 and 7880 AA. The mean 
epoch of the combined spectrum is 03:09:29 UT (5.12 hr after the 
GRB onset). Additionally, g, r, i, and z-band observations were 
obtained. We note that the coordinates of the afterglow are 
19:07:32.09, -16:25:05.8 (J2000 +/-0.5â€), which places the GRB 
approximately 5â€ away from those of the source identified by 
Lipunov et al. (GCN 21173) and Pozanenko et al. (GCN 21174). 
The afterglow can be also detected in the early Swift/UVOT 
images. In the acquisition image we measure a magnitude of 
r_AB = 21.9 for the afterglow, as compared to PANSTARRS 
catalogue field stars.

The afterglow spectrum shows continuum throughout the 
wavelength range and several strong absorption features 
corresponding to Lyman-alpha, SiII, OI, CII, SiIV, CIV, AlII and AlII 
at a common redshift of 2.366, which we identify as the redshift of 
the GRB.

[GCN OPS NOTE(01jun17): Per author's request, authors DPV, AN, & MH
were added to the list.]


GRB_name: GRB170531B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21178
SUBJECT: GROND observations of  GRB 170531B
DATE:    17/06/01 09:42:36 GMT
FROM:    Patricia Schady at MPE/Swift  <pschady@mpe.mpg.de>

P. Schady and T. Kruehler (both MPE) report

We observed the field of GRB 170531B (Swift trigger 755354; Evans et al.,
GCN #21171) 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 03:55 UT on 01-06-2017, 5.9 hours the GRB trigger.
They were performed at an average seeing of 1.3" and at an average airmass
of 1.3.

We detect a point source within the 1.8" enhanced Swift/XRT error circle
(Osborne et al., GCN #21175), and consistent with the afterglow position
reported by Ugarte Postigo et al. (GCN #21177).

Based on a total exposure of 54 min in g'r'i'z' and 45 min in JHK, we
estimate preliminary magnitudes (all in AB) of

g' = 22.65 +/- 0.04
r' = 22.15 +/- 0.04
i' = 21.99 +/- 0.05
z' = 21.84 +/- 0.06
J = 21.8 +/- 0.3
H = 21.5 +/- 0.3
K > 19.9

Given magnitudes are calibrated against PanSTARRS and 2MASS field stars
and are not corrected for the expected Galactic foreground extinction
corresponding to a reddening of E_(B-V)=0.16 mag in the direction of the
burst (Schlafly & Finkbeiner 2011).

We acknowledge the excellent support provided by the Chilean observer at
the telescope, and the support astronomer, Sam Kim, in obtaining these
data.


GRB_name: GRB170531B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21179
SUBJECT: GRB 170531B: MASTER Net  optical counterpart refind position and magnitude
DATE:    17/06/01 11:21:45 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

N.Tyurina, V. Lipunov, V.Kornilov, E.Gorbovskoy,  I.Gorbunov, D.Kuvshinov, 
A.V.Krylov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University, Sternberg Astronomical Institut of MSU

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

N.M.Budnev, O.Gres, O. Ershova
Irkutsk State University

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

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

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

R.Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA),
National University of San Juan, Argentina

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


MASTER-Kislovodsk robotic telescope (2x4 square degrees, MASTER-Net: 
http://observ.pereplet.ru)  was pointed to the  GRB170531B (Evans et al.,
GCN #21171)  12 sec after notice time and 452 sec after trigger time on 
2017-05-31 22:09:44 UT (Lipunov et al., GCN #21173).


Id      Date      time   Exp  Proc.type     Limit*  Tube  OT   Err
                        UT    sec                5sigma

1240587  2017-05-31 22:09:44  90 Alert (SWIFT)  18.3   EAST  18.3  0.5
1240589  2017-05-31 22:11:23 110 Alert (SWIFT)   18.4   EAST  18.4  0.5
1240591  2017-05-31 22:13:24 130 Alert (SWIFT)   18.5   EAST  18.4  0.5
1240593  2017-05-31 22:15:44 160 Alert (SWIFT)   18.5   EAST  18.5  0.5
1240596  2017-05-31 22:18:35 180 Alert (SWIFT)   18.5   EAST  18.5  0.5
1240652  2017-05-31 22:09:44 490 SumAlert(SWIFT) 19.1  EAST  18.3  0.2 
1240597  2017-05-31 22:21:59 180 Alert (SWIFT)   18.3   EAST   no    -
1240599  2017-05-31 22:25:24 180 Alert (SWIFT)   18.5   EAST   no    - 
.................................................................
1240629  2017-05-31 23:16:43 180 Alert (SWIFT)   18.5   EAST   no    -

* - unfiltered magnitude with respect to USNO B1.0 stars reference stars 
m=0.2B + 0.8R

We refind OT preliminary astrometric position  (Lipunov et al., GCN 
#21173) which was done visually.
Our refind position are:

RA,DEC = 19 07 32.19 -16 25 06.9

3 sigma error = (+/-)2 arcsec (the source is marginaly visible). Our pixel 
is 2 arcsec.

The offset from X-ray Swift position (Osborne at all) is 1.9 arcsec .

The position of the Postigo et al. ( GCN 21177) is inside our error box 
(offset ~ 1.9 arcsec).

The  possible OT position Pozanenko et al.( GCN #21174) offset ~ 8.2 arc 
sec.

The OT detection image is available.

The message may be cited.

====================================================================


The observations made on zenit distance = 64 degrees, galaxy latitude b = -11 
degree.
The moon (44 % bright part) below the horizon (The Moon altitude is -6 degree).
The sun  altitude  is -22.7 degree.
The object can be observed till sunrise at 2017-06-01 01:30:50 .



The message may be cited.


GRB_name: GRB170531A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21180
SUBJECT: GRB 170531A: Swift-XRT refined Analysis
DATE:    17/06/01 11:33:02 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), S. J. LaPorte (PSU),
J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), J.P. Osborne (U.
Leicester), K.L. Page (U. Leicester), B. Mingo (U. Leicester), V.
D'Elia (ASDC) and P.A. Evans report on behalf of the Swift-XRT team:

We have analysed 6.2 ks of XRT data for GRB 170531A (Evans et al. GCN
Circ. 21170), from 254 s to 44.6 ks after the  BAT trigger. The data
are entirely in Photon Counting (PC) mode. The best available XRT
position  (using the promptly downlinked event data, the XRT-UVOT
alignment and matching UVOT field sources to the USNO-B1 catalogue) is
RA, Dec = 121.2524, -14.0227 which is equivalent to:

RA (J2000): 08 05 00.57
Dec(J2000): -14 01 21.8

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=0.62 (+0.20, -0.16).

If the light curve continues to decay with a power-law decay index of
0.62, the count rate at T+24 hours will be 1.3 x 10^-3 count s^-1

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00755343.

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


GRB_name: GRB170531A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21181
SUBJECT: GRB 170531A: MASTER Net job
DATE:    17/06/01 12:23:54 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, N.Tyurina, E.Gorbovskoy, D.Kuvshinov, A.V.Krylov,
I.Gorbunov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University, Sternberg Astronomical Institut of MSU

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

D.Buckley
South African Astronomical Observatory


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

N.M.Budnev, O.Gres, O. Ershova
Irkutsk State University

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

R.Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA),
National University of San Juan, Argentina

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

MASTER-SAAO  robotic telescope (MASTER-Net: http://observ.pereplet.ru)
located in SAAO was pointed to the  GRB170531.84 25 sec after notice time
and 99 sec after trigger time at 2017-05-31 20:09:15 UT. On our first (20s
exposure)  set we haven't found optical transient  within SWIFT error-box
(ra=121.258 dec=-14.0328 r=0.05).
The 5-sigma upper limit has been about 15.5mag


The observations made on zenit distance = 84 degrees, galaxy latitude b =
10 degree.
The moon (43 % bright part) is 19 degrees above the horizon. The distance
between  moon and  object is 41
The sun  altitude  is -56.5 degree.


MASTER-IAC robotic telescope (2x4 square degrees, MASTER-Net: 
http://observ.pereplet.ru)  was pointed to the  GRB170531A (Evans et al.,
GCN #21170; Siegel et al. GCN #21172) 895 sec after notice time and 2115 
sec after trigger time on the 2017-05-31 20:42:48 UT.

The observations were made on zenit distance = 74 degrees during 
the twilight. The sun  altitude  was  -9.6 degree.
The moon (43 % bright part) is 58 degrees above the horizon. The distance 
between  moon and  object is 41deg.

On our 5-th (180s exposure)  set we haven't found optical 
transient  within SWIFT error-box (ra=121.258 dec=-14.0328 r=0.1).
The 5-sigma upper limit m~13.9mag (unfiltered) on the first image and


MASTER-OAFA  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in OAFA was pointed to the  GRB170531.84 15674 sec after notice 
time and 15751 sec after trigger time at 2017-06-01 00:30:03 UT. On our 
first (180s exposure)  set we haven't found optical transient  within 
Master error-box (ra=121.25 dec=-14.0225 r=0.1).
The 5-sigma upper limit has been about 18mag
The message may be cited.


The observations made on zenit distance = 63 degrees, galaxy latitude b = 
10 degree.
The moon (45 % bright part) is 38 degrees above the horizon. The distance 
between  moon and  object is 43
The sun  altitude  is -35.4 degree.
The object can be observed till 2017-06-01 02:41:37.


GRB_name: GRB170531B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21182
SUBJECT: GRB 170531B: Swift-XRT refined Analysis
DATE:    17/06/01 13:55:38 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

We have analysed 6.8 ks of XRT data for GRB 170531B (Evans et al. GCN
Circ. 21171), from 129 s to 52.1 ks after the  BAT trigger. The data
comprise 303 s in Windowed Timing (WT) mode (the first 10 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. 21175).

The late-time light curve (from T0+5.5 ks) can be modelled with a
power-law decay with a decay index of alpha=1.18 (+0.25, -0.20).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.45 (+/-0.04). The
best-fitting absorption column is  6.5 (+2.7, -2.5) x 10^21 cm^-2, at a
redshift of 2.366, in addition to the Galactic value of 1.4 x 10^21
cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index
of 2.07 (+0.13, -0.12) and a best-fitting absorption column consistent
with the Galactic value. The counts to observed (unabsorbed) 0.3-10 keV
flux conversion factor deduced from this spectrum  is 3.4 x 10^-11 (4.7
x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Galactic foreground: 1.4 x 10^21 cm^-2
Intrinsic column:    1.4 (+2.2, -0.0) x 10^21 cm^-2 at z=2.366
Photon index:      2.07 (+0.13, -0.12)

If the light curve continues to decay with a power-law decay index of
1.18, the count rate at T+24 hours will be 3.3 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x
10^-13 (1.6 x 10^-13) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00755354.

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


GRB_name: GRB170531B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21183
SUBJECT: GRB 170531B: LCO observations
DATE:    17/06/01 15:49:04 GMT
FROM:    Antonino Cucchiara at UVI  <antonino.cucchiara@uvi.edu>

A. Cucchiara, D. Morris (U. of Virgin Islands), C. Guidorzi
(U. Ferrara), reports on behalf of a larger collaboration:


"On June 1.00 UT  (T_0 +2.0h) we began observing the center
of the field of GRB 170531B (Evans et al. GCN 211171)
using the Las Cumbres Observatory 1m Sutherland facility.
We performed a series of 10x60s observations in R and I band
for a total of 10 minutes on sky in each filter. Seeing
conditions were poor.

We identified no optical counterpart within the center of
Swift-XRT refined position (Evans et al. GCN 21175), or at
the location of the identified  counterpart (Lipunov et al.
GCN 21173, Pozanenko et al. GCN 21174, Schady et al. GCN 21178)
at the following 3-sigma limits:

R > 19.9 mag
I > 19.6 mag

These magnitude are calibrated against nearby USNO-B1 sources,
and are not corrected for Galactic extinction."


GRB_name: GRB170531A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21184
SUBJECT: GRB 170531A: Swift/UVOT Upper Limits
DATE:    17/06/01 16:02:44 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@swift.psu.edu>

M. H. Siegel (PSU) 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 170531A
3523 s after the BAT trigger (Evans et al., GCN Circ. 21170).
No optical afterglow consistent with the XRT position
(Melandri et al., GCN Circ. 21180) is detected in the initial UVOT exposures.
We note that the XRT position is 3.5 away from a known USNO-B1 source, which
we detect. There is no indication of a second source within the error circle.
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          3523         3673          147         >18.1
white             3523         4292          344         >18.2
v                 4502         4702          197         >17.5
b                 3887         4087          197         >18.2
u                 3682         3881          197         >18.0
w2                4298         4497          197         >19.4

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.09 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB170531B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21186
SUBJECT: GRB 170531B: Swift-BAT refined analysis
DATE:    17/06/01 16:18:59 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

T. Sakamoto (AGU), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), P. A. Evans (U Leicester),
H. A. Krimm (NSF/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 170531B (trigger #755354)
(Evans et al., GCN Circ. 21171).  The BAT ground-calculated position is
RA, Dec = 286.901, -16.414 deg which is
  RA(J2000)  =  19h 07m 36.3s
  Dec(J2000) = -16d 24' 51.6"
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 96%.

The mask-weighted light curve shows a multi-peaked structure that starts
at ~T0 and ends at ~T+180 s. T90 (15-350 keV) is 164.13 +- 8.82 sec
(estimated error including systematics).

The time-averaged spectrum from T+0.55 to T+181.67 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.95 +- 0.14.  The fluence in the 15-150 keV band is 2.0 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+42.71 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/755354/BA/


GRB_name: GRB170531B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21187
SUBJECT: GRB 170531B: SMARTS optical/IR observations
DATE:    17/06/01 18:25:15 GMT
FROM:    Bethany Cobb at GWU  <bcobb@gwu.edu>

B. E. Cobb (GWU), reports:

Using the ANDICAM instrument on the 1.3m telescope at CTIO, we
obtained optical/IR imaging of the error region of GRB 170531B
(GCN 21171, Evans et al.) at two epochs (with mid-exposure times
of 2017-06-01 04:22 UT & 08:19 UT). For each epoch, several
dithered images were obtained with total summed exposure times
amounting to 36 minutes in I and 30 minutes in J.

No source is detected at the position of the X-ray/optical
afterglow (GCN 21175, Osborne et al.; GCN 21174, Pozanenko et al.;
GCN 21177, de Ugarte Postigo et al.; GCN 21178, Schady & Kruehler;
GCN 21179, Tyurina et al.) to the approximate 3-sigma limiting
magnitudes listed below:

mid-exposure
time post-burst
(hours)                I-limit    J-limit
 6.33056             >20.8    >18.5
10.27333            >21.2    >18.7

(Optical photometry is calibrated against USNO-B1.0 stars
and IR photometry is calibrated against 2MASS stars in the
field.)


GRB_name: GRB170531B
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21188
SUBJECT: GRB 170531B: Swift/UVOT Detection
DATE:    17/06/02 04:27:30 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@swift.psu.edu>

M. H. Siegel (PSU) 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 170531B
152 s after the BAT trigger (Evans et al., GCN Circ. 21171).
We detect a possible afterglow consistent with the position given by GTC
(de Ugarte Postigo et al., GCN Circ. 21177) and MASTER (Tyurin et al., 
GCN CIrc. 21179).

The preliminary UVOT position is:
    RA  (J2000) =  19:07:32.10 = 286.88373 (deg.)
    Dec (J2000) = -16:25:05.8  = -16.41829 (deg.)
with an estimated uncertainty of 0.1 arc sec. (radius, 90% confidence).

This position is 3.0 arc sec away from the enhanced XRT position
(Osborne et al. GCN Circ. 21175). Given the fading, detection
by other observatories and lack of matching source in the DSS, we find it
likely to be the GRB afterglow.

Preliminary 3-sigma magnitudes 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)         152          302          147         20.50+-0.29
white              590         1532          244         >21.03
v                  640         1581          116         >18.88
b                  566         1508           97         >19.77
u (fc)             310          560          245         >20.07
u                  713         1643           85         >19.17
uvw1               689         1630           97         >18.91
uvm2               664         1606          116         >18.88
uvw2               615         1557          116         >19.14

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.19 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB170531B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21189
SUBJECT: GRB 170531B: ISON/Terskol optical observations
DATE:    17/06/02 15:22:42 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI),   A. Mokhnatkin (KIAM),  A. Pozanenko (IKI), A. 
Volnova (IKI),   I. Molotov (KIAM)  report on behalf of  larger GRB 
follow-up collaboration:

We observed the field of GRB 170531B (Evans et al.,GCN  21171) with 
K-800 (0.8m) telescope  of ISON/Terskol   observatory starting  on May, 
31 (UT) 22:21:31.  We obtained several unfiltered images of 40 s 
exposure. The optical afterglow (Lipunov et al., GCN 21173 Pozanenko et 
al.  GCN 21174)  is clearly visible in combined images. Preliminary 
photometry of the afterglow is following


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

2017-05-31 22:21:31 0.01810 CR     18*40  18.90 0.10 21.0
2017-05-31 22:35:41 0.02949 CR     21*40  19.10 0.10 21.0

Photometry is based on nearby USNO-B1.0 stars
USNO-B.1_id R2
0736-0718845 16.77
0735-0729626 17.35
0735-0729622 16.96
0735-0729439 16.59
0735-0729327 17.22


GRB_name: GRB170604A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21191
SUBJECT: GRB 170604A: Swift detection of a burst
DATE:    17/06/04 19:29:03 GMT
FROM:    Kim Page at U.of Leicester  <klp5@leicester.ac.uk>

K. L. Page (U Leicester), A. Cholden-Brown (PSU),
N. P. M. Kuin (UCL-MSSL), A. Y. Lien (GSFC/UMBC) and
F. E. Marshall (NASA/GSFC) report on behalf of the Swift Team:

At 19:08:50 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 170604A (trigger=755867).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 342.645, -15.414 which is 
   RA(J2000) = 22h 50m 35s
   Dec(J2000) = -15d 24' 50"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a complex
structure with a duration of about 25 sec.  The peak count rate
was ~2400 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 19:10:55.1 UT, 124.7 seconds after
the BAT trigger. No source was detected in the 2.5-s promptly available
image. However, the XRT TDRSS light curve suggests the presence of a bright,
fading  source; since no Photon Counting mode data were collected, no prompt 
source localisation can be performed. We are waiting for the full dataset to 
detect and localise the XRT counterpart. 

No results from UVOT are available at 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: GRB170604A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21192
SUBJECT: GRB 170604A: optical observations
DATE:    17/06/04 20:17:53 GMT
FROM:    Luca Izzo at IAA-CSIC  <Luca.Izzo@ICRA.it>

L. Izzo, A. de Ugarte Postigo, Z. Cano, D.A. Kann (IAA-CSIC) report on behalf of a larger collaboration,

We observed the field of GRB 170604A (Page et al., GCN 21191) with the T27 (Plane Wave CDK 0.70m) of the iTelescope.Net (http://www.itelescope.net) located at Siding Spring, AU.  
A single image of 300 s each was taken in the R and in the V filters, starting at 19:32:07 UT, ~ 1400s after the GRB trigger. We detect a source not visible in PanSTARRS images at RA = 22:50:37.54 DEC = -15:24:44.4 (+- 0.5â€) with a preliminary magnitude of R ~ 17.5 (as compared to USNO-B 1.0 field stars), which we consider to be the afterglow. 

An image of the field can be seen at http://goo.gl/Rjmsk6


GRB_name: GRB170604A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21195
SUBJECT: GRB 170604A: Swift-BAT refined analysis
DATE:    17/06/05 02:19:40 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

M. Stamatikos (OSU), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
K. L. Page (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-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 170604A (trigger #755867)
(Page et al., GCN Circ. 21191).  The BAT ground-calculated position is
RA, Dec = 342.645, -15.406 deg which is
  RA(J2000)  =  22h 50m 34.9s
  Dec(J2000) = -15d 24' 20.1"
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 8%.

The mask-weighted light curve shows several overlapping pulses that start
at ~ T-12 s and end at ~T+20 s. The main peak occurs at ~T+3 s.
T90 (15-350 keV) is 26.70 +- 6.21 sec (estimated error including systematics).

The time-averaged spectrum from T-11.66 to T+22.58 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.31 +- 0.12.  The fluence in the 15-150 keV band is 5.1 +- 0.4 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+2.66 sec in the 15-150 keV band
is 4.2 +- 0.9 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/755867/BA/


GRB_name: GRB170604A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21196
SUBJECT: GRB 170604A: Enhanced Swift-XRT position
DATE:    17/06/05 08:03:35 GMT
FROM:    Kim Page at U.of Leicester  <klp5@leicester.ac.uk>

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

Using 4539 s of XRT Photon Counting mode data and 10 UVOT images, we find
an astrometrically corrected X-ray position (using the XRT-UVOT alignment
and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec =
342.65623, -15.41233 which is equivalent to:

RA (J2000):  22 50 37.49
Dec (J2000): -15 24 44.4

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 is an official product of the Swift-XRT team.


GRB_name: GRB170604A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21197
SUBJECT: GRB 170604A: GTC spectroscopic redshift
DATE:    17/06/05 08:04:01 GMT
FROM:    Zach Cano at U of Iceland  <zewcano@gmail.com>

L. Izzo, Z. Cano (IAA-CSIC), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), D.
A. Kann (IAA-CSIC), C. C. Thoene (IAA-CSIC), A. Marante (GTC) and S. Geier
(GTC, IAC) report on behalf of a larger collaboration:

We observed the afterglow of GRB 170604A (Page et al., GCN Circ. 21191)
using OSIRIS at the 10.4 m GTC telescope at La Palma (Spain). The
observation consisted of 2x900s and 1x1200s exposures using the R1000B
grism, which covers a wavelength range of 3700-7880 AA.  Observations began
at 04:14:19 UT on the morning of 05 June, 2017, at a mean epoch of +9.51
hrs from the GRB detection.  The afterglow candidate (Izzo et al, GCN Circ.
21192) is detected in the r-band acquisition image, where we measure r =
20.3 +- 0.1 relative to nearby PANSTARRS standards in the GRB field of
view.

The afterglow spectrum shows a continuum through the observed wavelength
range, and we identify absorption features corresponding to MgII, MgI, and
FeII at a common redshift of z=1.329, which we identify as the redshift of
GRB 170604A.


GRB_name: GRB170604A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21198
SUBJECT: GRB 170604A: Swift-XRT refined Analysis
DATE:    17/06/05 08:21:54 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), A. Cholden-Brown
(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 K.L. Page report on behalf of the Swift-XRT
team:

We have analysed 7.6 ks of XRT data for GRB 170604A (Page et al. GCN
Circ. 21191), from 110 s to 39.1 ks after the  BAT trigger. The data
comprise 308 s in Windowed Timing (WT) mode (the first 7 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. Using 4539 s of PC mode data and 10 UVOT images, we find an
enhanced XRT position (using the XRT-UVOT alignment and matching UVOT
field sources to the USNO-B1 catalogue): RA, Dec = 342.65623, -15.41233
which is equivalent to:

RA (J2000): 22h 50m 37.49s
Dec(J2000): -15d 24' 44.4"

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

The late-time light curve (from T0+3.8 ks) can be modelled with a
power-law decay with a decay index of alpha=0.98 (+/-0.05).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.27 (+/-0.04). The
best-fitting absorption column is  1.95 (+/-0.11) x 10^21 cm^-2, in
excess of the Galactic value of 3.8 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.85 (+/-0.09) and a
best-fitting absorption column of 6.9 (+2.3, -2.2) x 10^20 cm^-2. The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 3.6 x 10^-11 (4.0 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      6.9 (+2.3, -2.2) x 10^20 cm^-2
Galactic foreground: 3.8 x 10^20 cm^-2
Excess significance: 2.3 sigma
Photon index:      1.85 (+/-0.09)

If the light curve continues to decay with a power-law decay index of
0.98, the count rate at T+24 hours will be 0.046 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.6 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/00755867.

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


GRB_name: GRB170604A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21200
SUBJECT: GROND observations of GRB170604A
DATE:    17/06/05 11:20:22 GMT
FROM:    Patricia Schady at MPE/Swift  <pschady@mpe.mpg.de>

P. Schady (MPE) reports:

We observed the field of GRB 170604A (Swift trigger 755867; Page et al.,
GCN #21191) 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 06:15 UT on 05-06-2017, 11.1 hours the GRB
trigger. They were performed at an average seeing of 1.3" and at an
average airmass
of 2.

We detect a point source within the 1.4" enhanced Swift/XRT error circle
(Page et al., GCN 21196), and consistent with the afterglow position
reported by Izzo et al. (GCN #21192).

Based on a total exposure of 4.6 min in g'r'i'z' and 4 min in JHK, we
estimate preliminary magnitudes (all in AB) of

g' = 20.75 +/- 0.08
r' = 20.46 +/- 0.05
i' = 20.35 +/- 0.06
z' = 20.21 +/- 0.08
J = 19.6 +/- 0.1
H = 19.6 +/- 0.3
K > 19.6

Given magnitudes are calibrated against PanSTARRS and 2MASS field stars
and are not corrected for the expected Galactic foreground extinction
corresponding to a reddening of E_(B-V)=0.03 mag in the direction of the
burst (Schlafly & Finkbeiner 2011).

We acknowledge the excellent support provided by Simona Ciceri in
obtaining these data.


GRB_name: GRB170522A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21201
SUBJECT: GRB 170522A: confirmation of the X-ray afterglow
DATE:    17/06/05 14:08:44 GMT
FROM:    Kim Page at U.of Leicester  <klp5@leicester.ac.uk>

K.L. Page and S.L. Gibson (U. Leicester) report on behalf of the Swift-XRT
team:

Swift has performed further observations of the field of the
Fermi/LAT-detected burst GRB 170522A (Arimoto et al., GCN Circ. 21127). An
additional 3.5 ks of data were collected between 987 ks and 999 ks after
the Fermi trigger.

Source 1, initially reported by Mingo et al. (GCN Circ. 21133), is no
longer detected to a 3-sigma upper limit of 4.3e-3 ct s^-1. We therefore
conclude that this source is likely the X-ray afterglow of GRB 170522A.

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


GRB_name: GRB170604A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21203
SUBJECT: GRB 170604A: AbAO optical observations
DATE:    17/06/05 15:48:31 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI),  R. Inasaridze (AbAO), A. Pozanenko (IKI), A. Volnova 
(IKI),  V. Ayvazian  (AbAO),  O. Kvaratskhelia (AbAO), G. Inasaridze 
(AbAO), I. Molotov (KIAM), report on behalf of larger GRB follow-up 
collaboration:

We observed the field of the Swift  GRB 170604A (Page et al., GCN 21191) 
  with AS-32 (0.7m) telescope of Abastumani Observatory starting on 
June, 04 (UT)  23:52:07. We obtained several unfiltered images of the 
field.   Within enhanced XRT error circle  (Page et al., GCN   21196) we 
detected the afterglow (Izzo et al, GCN 21192; Izzo et al, GCN 21197; 
Schady, , GCN 21200). Preliminary photometry of the afterglow is following

Date        UT start   t-T0     Filter Exp.   OT   Err UpLim (3 sigma)
                       (mid, days)       (s)

2017-06-04 23:52:07   0.19950   CR     5*60  19.13 0.18  21.0
2017-06-05 00:00:50   0.20675   CR     7*60  19.23 0.16  21.1
2017-06-05 00:13:02   0.21885   CR    13*60  19.30 0.22  20.6

Photometry is based on nearby USNO-B1.0 stars (R2 magnitudes)
USNO-B.1_id    R2
0746-0830331 14.71
0746-0830367 14.76
0746-0830438 15.14
0746-0830455 14.77
0747-0821123 14.60

[GCN OPS NOTE(05jun17):  Per author's request, the duplicate text
of this circular was removed.]


GRB_name: GRB170604A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21204
SUBJECT: GRB 170604A: RATIR Optical and NIR Observations
DATE:    17/06/05 16:48:58 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), JesÃºs
GonzÃ¡lez (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM), Harvey Moseley (GSFC), John
Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:

We observed the field of GRB 170604A (Page, et al., GCN 21191) 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 2017/06 5.39 to 2017/06 5.45 UTC (14.19 to
15.70 hours after the BAT trigger), obtaining a total of 0.84 hours
exposure in the r and i bands and 0.42 hours exposure in the Z and Y bands.

For a source within the Swift-XRT error circle (Page, et al., GCN 21196),
in comparison with the USNO-B1 and 2MASS catalogs, we obtain the following
detections:

  r = 20.42 +/- 0.06
  i = 20.65 +/- 0.07
  Z = 20.45 +/- 0.13
  Y = 20.40 +/- 0.30

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: GRB170529A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21205
SUBJECT: GRB 170529A: AstroSat CZTI detection
DATE:    17/06/05 17:42:58 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

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

Analysis of Astrosat data showed the CZTI detection of a long bright GRB 170529A, which was also detected by IPN triangulation(Hurley et al., GCN 21165) and Konus-wind(Kozlova A., GCN 21167).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks emission with the strongest peak at 07:05:48.567 UT, ~7 s after the Konus-wind Trigger. The measured peak count rate is 1508.5 cts/s above the background in combined data of four quadrants, with a total of 17280 cts. The local mean background count rate was 390.5 cts/s. Using cumulative rates, we measure a T90 of 33.5 s.

It was clearly detected in the CsI anticoincidence detector (Veto) also as in the 100-500 keV energy range.

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: GRB170519A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21206
SUBJECT: GRB 170519A: Mondy optical observations
DATE:    17/06/05 19:07:17 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

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

We observed the field of GRB 170519A (Ukwatta et al., GCN 21106) with
AZT-33IK telescope of Sayan observatory (Mondy) starting on May 20 (UT) 
16:27:01. We took several images in R-filter with exposures of 120 s. 
The optical afterglow (Ukwatta et al., GCN 21106; Izzo, et al., GCN 
21108) is clearly visible in single images.

We continued our observations on May 27 (UT) 16:28:02, i.e., ~8.5 days
after the BAT trigger. We took several R-filtered images. We do not 
detect the optical counterpart in the enhanced XRT error circle 
(Beardmore et al., GCN 21107).

Preliminary photometry of the afterglow is following:

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

2017-05-20 16:27:01  1.47708  R   10*120  19.99 0.03 22.8
2017-05-20 17:07:02  1.50487  R   10*120  19.99 0.03 22.6
2017-05-27 16:28:02  8.49905  R   39*120  n/d   n/d  22.6

The photometry is based on nearby SDSS stars reported by
Mazaeva et al. (GCN 21169).


GRB_name: GRB170604A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21207
SUBJECT: GRB 170604A: Swift/UVOT Observations
DATE:    17/06/05 19:10:10 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@swift.psu.edu>

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

The Swift/UVOT began settled observations of the field of GRB 170604A
128 s after the BAT trigger (Page et al., GCN Circ. 21191).
We detect a fading afterglow consistent with the position given by XRT
(Page et al., GCN Circ 21196) and ground-based optical detections
(Izzy et al., GCN Circ 21197; Schady, GCN Circ. 21200; Mazaeva et al., 
GCN Circ 21203).

The preliminary UVOT position is:
    RA  (J2000) =  22:50:37.52 = 342.65632 (deg.)
    Dec (J2000) = -15:24:43.9  = -15.41220 (deg.)
with an estimated uncertainty of 0.1 arc sec. (radius, 90% confidence).

Preliminary magnitudes and 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)         128          278          147          15.81+-0.03
white             3968         5603          393          18.72+-0.06
white            39053        39959          885          20.57+-0.18
v                 4378         6013          393          18.94+-0.31
v                34480        44756         1268         >19.89
b                 3763         5398          393          19.26+-0.15
b                38141        39048          885         >20.86
u (fc)             287          429          279          15.70+-0.03
u                 4993         5193          196          18.51+-0.16
u                28543        29132          576         >19.72
uvw1              4788         4988          196          18.47+-0.19
uvw1             23318        46354         1633          20.20+-0.27
uvm2              4583         6169          344          18.58+-0.18
uvm2             44762        45661          885         >20.37
uvw2              4174         5809          393          19.53+-0.26
uvw2             32392        40613         1700         >20.86

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.04 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB170519A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21208
SUBJECT: GRB 170519A: TShAO and AbAO optical observations
DATE:    17/06/05 19:41:04 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI), A. Pozanenko (IKI), A. Kusakin (Fesenkov Astrophysical 
Institute),  R. Inasaridze (AbAO), I. Reva (Fesenkov Astrophysical 
Institute), A. Volnova (IKI),  V. Ayvazian  (AbAO),  O. Kvaratskhelia 
(AbAO), G. Inasaridze (AbAO), I. Molotov (KIAM) report on behalf of 
larger GRB follow-up collaboration:

We observed the field of GRB 170519A (Ukwatta et al., GCN 21106) with 
Zeiss-1000 1-m telescope of Tien Shan Astronomical Observatory
starting on May 20 (UT) 18:42:38. We took several images in R-filter
with exposures of 120 s during this night and 2 subsequent nights.
The optical afterglow (Ukwatta et al., GCN 21106; Izzo, et al.,
GCN 21108) is visible in stacked images.

We also observed this field with AS-32 (0.7m) telescope of Abastumani
Observatory on May 21 (UT) 17:22:33. We took several unfiltered frames
with 60 s exposure. In the enhanced XRT error circle (Beardmore et al.,
GCN 21107) we do not detect the afterglow.

Preliminary photometry of the afterglow is following:

Date       UT start   t-T0    Filter Exp.   OT   Err. UL    Telescope
                      (mid, days)     (s)              (3 sigma)

2017-05-20 18:42:38  1.58414  R    24*120  20.06 0.06 21.4 Zeiss-1000
2017-05-21 15:58:25  2.48340  R    39*120  20.95 0.14 21.6 Zeiss-1000
2017-05-22 15:27:05  3.46168  R    39*120  22.20 0.40 21.9 Zeiss-1000
2017-05-21 17:22:33  2.52050  CR   20*60   n/d   n/d  20.8 AS-32

The photometry is based on nearby SDSS stars, reported by
Mazaeva et al. (GCN 21169).

The  light curve of the GRB 170519A afterglow based on our observations 
  (GCNs 21162, 21169, 21206)  can be found at
http://grb.rssi.ru/GRB170519A/GRB170519A_lc.png


GRB_name: GRB170531B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21209
SUBJECT: GRB 170531B: WHT spectroscopy
DATE:    17/06/07 09:17:35 GMT
FROM:    Klaas Wiersema at U Leicester  <kw113@leicester.ac.uk>

K. Wiersema, N. Tanvir (Leicester), A. Levan (Warwick) report:

We observed the afterglow of GRB 170531B (Evans et al. GCN 21171; Lipunov et al. GCN 21173; 
Pozanenko et al. GCN 21174) with the 4.2m William Herschel Telescope on La Palma, using the 
ACAM instrument. We obtained a spectrum, consisting of 4x900 seconds exposure time, starting 
at 02:55 UT on 1 June 2017. Our wavelength coverage is ~4500 - 9500 A. We detect a small 
number  metal lines (at low S/N) at a redshift consistent with that obtained by de Ugarte-Postigo 
et al. (GCN 21177).

We warmly thank the staff of ING, in particular Raine Karjalainen, for their assistance.


GRB_name: GRB170531B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21210
SUBJECT: GRB 170531B: Zeiss-1000/CrAO optical observations
DATE:    17/06/07 21:38:36 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI), A. Pozanenko (IKI),  D. Chestnov (ISON), A. Novichonok 
(ISON), V. Agletdinov (KIAM), I. Nikolenko (CrAO),  A. Volnova (IKI), 
report on behalf of larger GRB follow-up collaboration:

We report refined analysis of Zeiss-1000/CrAO observations. Results 
reported below supersede GCN cir. 21174.
We observed the field of the GRB 170531B (Evans et al., GCN  21171) with 
Zeiss-1000/Koshka (CrAO) telescope  between May 31 (UT) 22:32:32 and 
June 01 (UT)  00:58:11. We took several unfiltered images with
exposure of 180 s. The afterglow  (Lipunov et al. GCN 21173;
Pozanenko et al. GCN 21174) is clearly visible in each image in first 
initial images, and detected later in combined images. The finding chart 
of the combined image can be found at
http://grb.rssi.ru/GRB170531B/GRB170531B_Koshka_170531_sources.png

The coordinates of the afterglow (source A in the finding chart) are 
(J2000) 19:07:32.10 -16:25:06.0 with uncertainty of 0.5 arcsec in both 
coordinates. The coordinates are consistent with the position reported 
by  de Ugarte Postigo et al., GCN 21177, Tyurina et al., GCN   21179, 
and Siegel et al., GCN 21188.


Preliminary photometry of the afterglow can be found in the light curve at
http://grb.rssi.ru/GRB170531B/GRB170531B_light_curve_v2.png

The photometry is based on nearby USNO-B1.0 stars, calibrated against to 
R2 magnitudes
USNO-B.1_id  R2
0736-0718845 16.77
0735-0729622 16.96
0735-0729439 16.59
0735-0729327 17.22

Due to presence of sources in near vicinity to the afterglow the 
photometry of wide FOV telescopes might be affected by the sources. In 
particular our photometry reported in GCN 21189 is apparently biased by 
the two sources C and D (see the finding chart). We report coordinates 
and brightness of the nearby sources.

Source  coordinates(J2000)          AG distance  filter  mag.   err.
C       19:07:32.34 -16:25:09.1     4.6"         CR      20.46  0.04
D       19:07:31.83 -16:25:05.6     3.9"         CR      20.47  0.04


GRB_name: GRB170519A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21211
SUBJECT: GRB 170519A: 15 GHz upper limits from AMI
DATE:    17/06/07 22:36:01 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 
170519A (Ukwatta et al., GCN 21106) 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 May 19.61, May 20.84, May 
23.74 and May 27.78 (UT) do not reveal any radio source at the XRT 
location (Beardmore et al., GCN 21107), with 3sigma upper limits of 228 
uJy, 190 uJy, 150 uJy, and 100 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: GRB170524A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21212
SUBJECT: GRB 170524A: 15 GHz upper limits from AMI
DATE:    17/06/07 22:38:43 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
170524A (Gropp et al., GCN 21135) 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 May 25.03, May 26.26, May
28.18 and Jun 01.20 (UT) do not reveal any radio source at the XRT
location (Evans et al., GCN 21136), with 3sigma upper limits of 162 uJy,
207 uJy, 120 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: GRB170526A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21213
SUBJECT: GRB 170526A: 15 GHz upper limits from AMI
DATE:    17/06/07 22:39:09 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 
170526A (Sbarufatti et al., GCN 21149) 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 May 27.16, May 30.29, May 
31.33 and Jun 03.28 (UT) do not reveal any radio source at the XRT 
location (Goad et al., GCN 21151), with 3sigma upper limits of 312 uJy, 
117 uJy, 96 uJy and 105 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: GRB170607A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21214
SUBJECT: GRB 170607A: Swift detection of a burst with a bright optical counterpart
DATE:    17/06/07 23:32:47 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

A. D'Ai (INAF-IASFPA), D. N. Burrows (PSU), A. Cholden-Brown (PSU),
V. D'Elia (ASDC), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL),
B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf
of the Swift Team:

At 23:21:33 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 170607A (trigger=756284).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 7.343, +9.238 which is 
   RA(J2000) = 00h 29m 22s
   Dec(J2000) = +09d 14' 16"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single FRED
structure with a duration of about 40 sec.  The peak count rate
was ~4000 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 23:22:47.1 UT, 73.4 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 7.3655, 9.2425 which is equivalent to:
   RA(J2000)  = +00h 29m 27.72s
   Dec(J2000) = +09d 14' 33.0"
with an uncertainty of 4.8 arcseconds (radius, 90% containment). This
location is 81 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 5.32e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 83 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 00:29:27.80 = 7.36582
  DEC(J2000) = +09:14:36.2  = 9.24339
with a 90%-confidence error radius of about 0.61 arc sec. This position is 3.4
arc sec. from the center of the XRT error circle. The estimated magnitude is
15.90 with a 1-sigma error of about  0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.04. 

Burst Advocate for this burst is A. D'Ai (antonino.dai AT ifc.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: GRB170607A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21215
SUBJECT: GRB 170607A: Enhanced Swift-XRT position
DATE:    17/06/08 02:43:48 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 1379 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 170607A, 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 = 7.36612, +9.24329 which is equivalent
to:

RA (J2000): 00h 29m 27.87s
Dec (J2000): +09d 14' 35.8"

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: GRB170607A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21216
SUBJECT: GRB 170607A: Swift-XRT refined Analysis
DATE:    17/06/08 07:07:40 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

D.N. Burrows (PSU), A. Cholden-Brown (PSU), A.P. Beardmore (U.
Leicester), P.A. Evans (U. Leicester), S.L. Gibson (U. Leicester), A.
Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), S. J. LaPorte (PSU) and A.
D'Ai report on behalf of the Swift-XRT team:

We have analysed 7.5 ks of XRT data for GRB 170607A (D'Ai et al. GCN
Circ. 21214), from 63 s to 19.1 ks after the  BAT trigger. The data
comprise 395 s in Windowed Timing (WT) mode (the first 8 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Beardmore
et al. (GCN Circ. 21215).

The late-time light curve (from T0+5.1 ks) can be modelled with a
power-law decay with a decay index of alpha=0.54 (+/-0.09).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.003 (+0.038, -0.019). The
best-fitting absorption column is  consistent with the Galactic value
of 4.4 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has
a photon index of 1.92 (+/-0.08) and a best-fitting absorption column
of 7.1 (+1.9, -1.8) 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 (3.9 x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      7.1 (+1.9, -1.8) x 10^20 cm^-2
Galactic foreground: 4.4 x 10^20 cm^-2
Excess significance: 2.5 sigma
Photon index:      1.92 (+/-0.08)

If the light curve continues to decay with a power-law decay index of
0.54, the count rate at T+24 hours will be 0.13 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.3 x
10^-12 (5.0 x 10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00756284.

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


GRB_name: GRB170607A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21217
SUBJECT: GRB 170607A: NOT optical afterglow detection
DATE:    17/06/08 08:39:04 GMT
FROM:    Kasper Elm Heintz at Univ. of Iceland and DARK/NBI  <heintz@dark-cosmology.dk>

K.E. Heintz (Univ. of Iceland and DARK/NBI), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), and J. Claesen (NOT) report on behalf of a larger collaboration, 

We have observed the field of GRB 170607A (Dâ€™Ai et al., GCN 21214) with the 2.5m Nordic Optical Telescope at La Palma, Spain. The observations consisted of 3x180s in the Sloan g-, r- and i-bands and were carried out at a mid-time of 04:23:59 UT (i.e. 5.03 hr after the burst). The bright afterglow is well detected in all the individual frames. From the reduced and combined images we measure magnitudes of:

g(AB) = 18.57 +/- 0.08 mag
r(AB) = 18.36 +/- 0.06 mag
i(AB) = 18.22 +/- 0.05 mag

calibrated against nearby SDSS field stars.

We also note the presence of a galaxy at a photometric redshift of 0.632 in the SDSS images, close to the location of the burst, which we identify as a host galaxy candidate.


GRB_name: GRB170607A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21218
SUBJECT: GRB 170607A: Fermi GBM observation
DATE:    17/06/08 09:02:25 GMT
FROM:    Elisabetta Bissaldi at U.Innsbruk/IAPP  <Elisabetta.Bissaldi@uibk.ac.at>

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


"At 23:17:59.57 UT on 07 June 2017, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 170607A (trigger 518570284 / 170607971),
which was also detected by the Swift/BAT (D'Ai et al. 2017, GCN 21214).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 100 degrees.

The GBM light curve consists of a sharp peak
with a duration (T90) of about 23 s (50-300 keV).
The time-averaged spectrum from T0-2.4 s to T0+14.0 s is
adequately fit by a power law function with an exponential
high-energy cutoff. The power law index is -1.40 +/- 0.04 and
the cutoff energy, parameterized as Epeak, is 154 +/- 13 keV.

The event fluence (10-1000 keV) in this time interval is
(9.6 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+2.1 s in the 10-1000 keV band
is 15.5 +/- 0.6 ph/s/cm^2.


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


GRB_name: GRB170607A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21219
SUBJECT: GRB 170607A: MASTER-Tavrida  early OT observations
DATE:    17/06/08 11:05:09 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, N.Tyurina, V.Kornilov, E.Gorbovskoy,  A.Kuznetsov, 
V.Vladimirov,  I.Gorbunov, D.Kuvshinov,  A.V.Krylov, P.Balanutsa, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University, Sternberg Astronomical Institut of MSU

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

N.M.Budnev, O.Gres, O. Ershova
Irkutsk State University

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

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

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

R.Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA),
National University of San Juan, Argentina

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

MASTER-Tavrida robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in Crimea Astronomical station of  Lomonosov Moscow State 
University pointed to the FERMI  GRB 170607A  error-box (ra=00 37 55 
dec=+07 46 10  r=1.53, see Hamburg and Meegan GCN #21218)  25 sec after 
Fermi GBM notice time and 63 sec after  Fermi GBM trigger time at 
2017-06-08 23:19:03 UT. This was 150 sec before Swift trigger (D'Ai et 
al., GCN #21214).

MASTER-Tavrida robotic telescope repointed to Swift BAT error box (D'Ai et
al., GCN #21214)  25 sec after Swift Notice Time and 42 sec after Swift 
trigger  at  2017-06-07 23:22:15 UT . We see OT at first image with 10 sec 
exposition.  We have OT light curve starting before maximum (UT_max = ~ 
23h 24m)  up to 2017-06-08 00:40:52 UT:

UT_max = 23:23:45 +/- 10sec

OT unfiltered magnitude (max) = 16.4 +- 0.1

RA,DEC = 00h 29m 27s.8 + 9d 14m 35s.8
Error = 0.5 arcsec

Position is coincide with UVOT position (D'Ai et al., GCN #21214).

We see  rebrighting or plato starting at 2017-06-07 23:52:43 UT (~30 min 
after  Swift  trigger).

The message may be cited.


GRB_name: GRB170607A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21220
SUBJECT: GRB 170607A: Swift/UVOT Detection
DATE:    17/06/08 12:56:36 GMT
FROM:    Sam Emery at MSSL-UCL  <samuel.emery.15@ucl.ac.uk>

S.W.K. Emery (UCL-MSSL) and A. D'Ai (INAF-IASFPA)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 170607A
84 s after the BAT trigger (D'Ai et al., GCN Circ. 21214).
GRB 170607A was also triggered by Fermi GBM
(Hamburg and Meegan GCN Circ. 21218)
We detect a fading afterglow consistent with the position given by XRT
(Beardmore et al., GCN Circ. 21215) and ground-based optical detections
(Heintz et al., GCN Circ. 21217; Lipunov et al., GCN Circ. 21219).

The preliminary UVOT position is:
    RA  (J2000) =  00:29:27.82 =   7.36591 (deg.)
    Dec (J2000) = +09:14:36.0  =   9.24334 (deg.)
with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).

Preliminary detections 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            84          233          147         15.76 +/- 0.02
white              575         5285          461         17.11 +/- 0.03
white             6895         7065          197         17.50 +/- 0.04
v                  625         5696          313         17.51 +/- 0.11
b                  551         1859          132         17.63 +/- 0.09
u_FC               295          545          246         16.14 +/- 0.04
u                  699         6205          210         16.80 +/- 0.06
u                 6454        29372         1601         17.68 +/- 0.04
uvw1               847         6105          313         16.87 +/- 0.06
uvm2              5700         5900          197         16.86 +/- 0.09
uvw2              1720         5491          216         17.04 +/- 0.07


The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.04 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB170607A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21225
SUBJECT: GRB 170607A: Correction on the possible host galaxy identification
DATE:    17/06/08 17:54:18 GMT
FROM:    Kasper Elm Heintz at Univ. of Iceland and DARK/NBI  <heintz@dark-cosmology.dk>

K. E. Heintz (Univ. of Iceland and DARK/NBI), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), and S. Schulze (Weizmann Institute) report on behalf of a larger collaboration, 

In our previous GCN (Heintz et al., GCN 21217) we reported a possible SDSS host galaxy at z=0.632. We note, however, that this identification was incorrect, as this galaxy lies a few arcseconds away from the GRB afterglow. However, further analysis of SDSS and Pan-STARRS images do show a possible host galaxy lying just 0.â€8 of the afterglow position as measured by UVOT, with a faintness around the Pan-STARRS r-band detection limit.


GRB_name: GRB170607A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21230
SUBJECT: GRB 170607A: Swift-BAT refined analysis
DATE:    17/06/09 03:15:15 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), A. D'Ai (INAF-IASFPA),
H. A. Krimm (NSF/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+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 170607A (trigger #756284)
(D'Ai et al., GCN Circ. 21214).  The BAT ground-calculated position is
RA, Dec = 7.358, 9.225 deg which is
  RA(J2000)  =  00h 29m 26.0s
  Dec(J2000) = +09d 13' 30.8"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 57%.

The mask-weighted light curve show two prominent pulses. The first pulse
starts before it came into the BAT FOV at T0-217.9 s during a preplanned
spacecraft slew. It peaks at ~T0-210 s and ends at ~T0-190 s. The second
pulse starts at ~T0-10 s, peaks at T0, and ends at ~T0+40 s, with a tail
lasting till ~T0+140 s.

The time-averaged spectrum from T0-207.896 to T0+144.104 s is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.61 +- 0.07.  The fluence in the 15-150 keV band is 7.5 +- 0.3 x 10^-6 erg/cm2.
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/756284/BA/


GRB_name: GRB170607B
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21232
SUBJECT: GRB 170607B: AstroSat CZTI detection
DATE:    17/06/09 12:09:39 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

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

Routine on-ground analysis of AstroSat CZT Imager data showed the detection of a bright GRB 170607B, which was also detected by Fermi GBM (designation: bn170607946) at 2017-06-07 22:41:58.947 UT.

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with the strongest peak at 22:42:04.947 UT, ~6 s after the Fermi Trigger. The measured peak count rate is 496.1 cts/s above the background in combined data of four quadrants, with a total of 7677 cts. The local mean background count rate was 354.9 cts/s. Using cumulative rates, we measure a T90 of 21.8 s.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

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: GRB170607A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21237
SUBJECT: GRB 170607A: ISON/Terskol optical observations
DATE:    17/06/09 18:33:32 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

A. Volnova (IKI),  A. Pozanenko (IKI), V. Agletdinov (KIAM),  E. Mazaeva 
(IKI), A. Mokhnatkin (KIAM),   I. Molotov (KIAM)  report on behalf of 
larger GRB follow-up collaboration:

We observed the field of GRB 170607A (Dâ€™Ai et al., GCN 21214) with K-800 
(0.8m) telescope  of ISON/Terskol   observatory starting  on June, 08 
(UT) 23:23:04, about 1 day after the burst onset.  We obtained several 
unfiltered images of 20 s exposure. The optical afterglow (Dâ€™Ai et al., 
GCN 21214; Heintz  et al., GCN 21217; Lipunov et al., GCN 21220)  is 
still bright and clearly visible in a combined image. Preliminary 
photometry of the afterglow is following


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

2017-06-08 22:21:31 1.01959 CR      128*20 18.50 0.28 18.90


Photometry is based on nearby SDSS DR9 stars
SDSS id                   R_Lupton
J002930.50+091415.3       16.314
J002920.28+091527.1       15.963
J002925.73+091637.7       14.803


GRB_name: GRB170607B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21238
SUBJECT: GRB 170607B: Fermi GBM detection
DATE:    17/06/09 19:27:07 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007@uah.edu>

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

"At 22:41:58.95 UT on 07 June 2017, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 170607B (trigger 518568123 / 170607946)
which was also detected by the AstroSat CZTI
(Sharma et al. 2017, GCN 21232).

The on-ground calculated location, using the GBM trigger
data, is RA = 257.1, DEC = -35.7, with an uncertainty
of 1.5 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 99
degrees.

The GBM light curve consists of a spiked structure
with a duration (T90) of about 18 s (50-300 keV).
The time-averaged spectrum from T0-5.1 s to T0+22.5 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.77 +/- 0.02 and
the cutoff energy, parameterized as Epeak, is 627 +/- 21 keV.

The event fluence (10-1000 keV) in this time interval is
(5.9 +/- 0.1)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+20.4 s in the 10-1000 keV band
is 12.0 +/- 0.4 ph/s/cm^2.

A Band function fits the spectrum equally well
with Epeak= 619 +/- 22 keV, alpha = -0.76 +/- 0.02 and beta =
-3.5 +/- 0.7.

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


GRB_name: GRB170607A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21240
SUBJECT: GRB 170607A: Redshift from GTC/OSIRIS
DATE:    17/06/10 07:33:46 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), L. Izzo (IAA-CSIC), 
C.C. Thoene (IAA-CSIC), Z. Cano (IAA-CSIC), D. A. Kann (IAA-CSIC), 
R. Scarpa (GTC), and V. Herrera (GTC) report on behalf of a larger 
collaboration:

We observed the afterglow of GRB 170607A (Dâ€™Ai et al. GCN 21214, 
Heintz et al. GCN 21217, Lipunov et al. GCN 21219, Volnova et al. 
GCN 21237) using OSIRIS at the 10.4m GTC telescope. Observation 
consisted of 3x900s using grism R1000R, which covers the range 
between 5100 and 10100 Ã…, at a mean epoch of 10.1955 June 2017 
UT (2.2222 days after the GRB).

The acquisition image still shows a bright afterglow at r(AB) = 20.70 
+/- 0.05 mag, as compared to SDSS field stars. In spite of the strong 
contribution from the afterglow, no clear absorption features can be 
detected in this spectral range. However, there are strong emission 
lines due to [OII], [OIII], and H-beta at a common redshift of 0.557, 
which we identify as the redshift of the GRB.


GRB_name: GRB170607B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21242
SUBJECT: IPN Triangulation of GRB 170607B
DATE:    17/06/10 14:15:43 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 long-duration GRB 170607B (Sharma et al., GCN Circ. 21232;
Hamburg et al., GCN 21238) has been detected by Konus-Wind,
Fermi (GBM), INTEGRAL (SPI-ACS), Mars-Odyssey (HEND), and
AstroSat (CZTI), so far, at about 81720 s UT (22:42:00).

We have triangulated it to a preliminary, 3 sigma error box whose
coordinates are:
---------------------------------------------
  RA(2000), deg                 Dec(2000), deg
 ---------------------------------------------
 Center:
  246.661 (16h 26m 39s) -39.159 (-39d 09' 32")
 Corners:
  245.286 (16h 21m 09s) -37.113 (-37d 06' 45")
  247.857 (16h 31m 26s) -41.075 (-41d 04' 30")
  248.366 (16h 33m 28s) -41.126 (-41d 07' 34")
  245.736 (16h 22m 57s) -37.211 (-37d 12' 39")
 ---------------------------------------------
The error box area is 1.3 sq. deg, and its maximum
dimension is 4.67 deg (the minimum one is 17.8 arcmin).
The Sun distance was 160 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB170607_T81725/IPN/

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


GRB_name: GRB170610A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21243
SUBJECT: GRB 170610A: MAXI/GSC detection
DATE:    17/06/10 23:40:16 GMT
FROM:    Motoko Suzuki at RIKEN  <motoko@crab.riken.jp>

M. Shidatsu, S. Motoko (RIKEN), H. Negoro (Nihon U.), 
S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N. Isobe (JAXA),
T. Mihara, M. Sugizaki, S. Nakahira, W. Iwakiri, M. Matsuoka (RIKEN), 
N. Kawai, S. Sugita, T. Yoshii, Y. Tachibana, S. Harita, Y. Muraki, K. Morita (Tokyo Tech), 
A. Yoshida, T. Sakamoto, Y. Kawakubo, Y. Kitaoka, T. Hashimoto (AGU), 
H. Tsunemi, T. Yoneyama (Osaka U.), 
M. Nakajima, T. Kawase, A. Sakamaki (Nihon U.),
Y. Ueda, T. Hori, A. Tanimoto, S. Oda (Kyoto U.), 
Y. Tsuboi, Y. Nakamura, R. Sasaki (Chuo U.), 
M. Yamauchi, C. Hanyu, K, Hidaka (Miyazaki U.), 
T. Kawamuro (NAOJ), 
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 UT 20:42:58 UT on 2017 June 10. 
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (92.567 deg, -9.420 deg) = (06 10 16, -09 25 11) (J2000)
with a statistical 90% C.L. elliptical error region
with long and short radii of 0.24 deg and 0.2 deg, respectively.
The roll angle of long axis from the north direction is 123.0 deg counterclockwise. 
We estimated a rectangular error box for the transient source with the following corners:
(91.851, -10.701) deg = (06 07 24, -10 42 03) (J2000)
(91.421, -10.332) deg = (06 05 40, -10 19 54) (J2000)
(92.681, -8.737) deg = (06 10 43, -08 44 13) (J2000)
(93.111, -9.105) deg = (06 12 26, -09 06 16) (J2000).
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).

The X-ray flux averaged over the scan was 127 +- 23 mCrab
(4.0-10.0keV, 1 sigma error).
There was no significant excess flux in the previous transit at UT 19:10
and in the next transit at UT 22:15 with an upper limit of 20 mCrab for each.


GRB_name: GRB170607B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21246
SUBJECT: Konus-Wind observation of GRB 170607B
DATE:    17/06/11 13:36:09 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 long GRB 170607B (AstroSat CZTI detection: Sharma et al., GCN 21232;
Fermi GBM detection: Hamburg et al., GCN 21238;
IPN triangulation: Hurley et al., GCN 21242)
triggered Konus-Wind at T0=81725.036 s UT (22:42:05.036).

The burst light curve shows a bright, multi-peaked pulse
which started at ~T0-9 s an had a total duration of ~35 s.
A weak count rate increase is also visible around ~T0+100 s
The emission is seen up to ~10 MeV.

As observed by Konus-Wind, the burst had a fluence of
(7.2 Â± 0.8)x10^-5 erg/cm2 and a 64-ms peak energy flux,
measured from T0+18.752 s of (8.1 Â± 1.2)x10^-6 erg/cm2
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+22.528 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.77 (-0.07,+0.08),
the high energy photon index beta = -2.87 (-1.27,+0.40),
the peak energy Ep = 512 (-50,+49) keV,
chi2 = 105/97 dof.

The spectrum near the peak count rate (measured from T0+14.336
to T0+22.528 s) is best fit in the 20 keV - 5 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.58 (-0.32,+0.38),
the high energy photon index beta = -2.22 (-1.17,+0.22),
the peak energy Ep = 244 (-51,+103) keV,
chi2 = 70/72 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB170607_T81725/

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


GRB_name: GRB170604A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21247
SUBJECT: Konus-Wind observation of GRB 170604A
DATE:    17/06/11 15:27:18 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 long GRB 170604A (Swift-BAT trigger #736407: Page et al.,
GCN 21191; Stamatikos et al., GCN 21195; T0(BAT)=17:08:50.402 UT)
was detected by Konus-Wind (KW) in the waiting mode.

The light curve shows a single peak with a duration of ~30 s.
Modeling the KW 3-channel time-integrated spectrum
(from T0(BAT)-16.155 s to T0(BAT)+10.341 s) by
a power law with exponential cutoff (CPL) model
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha = -1.31(-0.20,+0.26) and Ep = 220(-48,+72) keV.
The energy fluence for this time interval is (1.03 Â± 0.13)x10^-5
erg/cm2, and the peak energy flux, measured on a 2.944 s scale from
T0(BAT)+1.509 s is (6.9 Â± 0.13)x10^-7 erg/cm2/s, both in the
20 keV-10 MeV range.

Assuming the redshift z=1.329 (Izzo et al., GCN 21197)
and a standard cosmology model with H_0 = 70 km/s/Mpc,
Omega_M = 0.30, and Omega_Lambda = 0.70, we estimate the burst
isotropic energy release E_iso to (4.7 Â± 0.6)x10^52 erg,
and the rest-frame peak energy of the time-integrated spectrum,
Ep,z, to 512(-112,+168) keV.

The K-W light curve of this burst is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB170604A/

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


GRB_name: GRB170606A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21254
SUBJECT: GRB 170606A CALET Gamma-Ray Burst Monitor detection
DATE:    17/06/16 03:45:35 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

K. Yamaoka (Nagoya U), A. Yoshida, T. Sakamoto, Y. Kawakubo, M. Moriyama,
Y. Yamada, A. Tezuka, S. Matsukawa (AGU), S. Nakahira (RIKEN), 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),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long-duration GRB 170606A (Fermi-GBM trigger #518483662)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 23:14:14.82
on 6 June 2017.  The burst signal was seen only by the SGM instrument.

The light curve of the SGM shows a single peak.  The emission starts
at T+3 sec, peaks at T+4.5 sec and ends at T+8 sec.  The T90 duration
measured by the SGM data is 3.9 +- 0.4 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1180825585/

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


GRB_name: GRB170614A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21255
SUBJECT: GRB 170614A CALET Gamma-Ray Burst Monitor detection
DATE:    17/06/16 23:00:32 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

I. Takahashi (IPMU), A. Yoshida, T. Sakamoto, Y. Kawakubo,
M. Moriyama, Y. Yamada, A. Tezuka, S. Matsukawa (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), 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),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long-duration GRB 170614A (Fermi-GBM trigger #519133191;
INTEGRAL SPI-ACS trigger #7869; Konus-Wind trigger time on
11:39:55.892) triggered the CALET Gamma-ray Burst Monitor (CGBM)
at 11:39:43.86 on 14 June 2017.  The burst signal was seen by the all
CGBM instruments.

The light curve of the SGM shows multiple peaks.  The entire
burst episode starts at T+~2 sec, peaks at T+~20 sec and ends
at T+~40 sec.  The T90 duration measured by the SGM data is
22 +- 1 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1181475101/

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


GRB_name: GRB170614A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21256
SUBJECT: GRB 170614A: AstroSat CZTI detection
DATE:    17/06/19 10:49:18 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

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

Analysis of Astrosat CZTI data showed the detection of a long-duration GRB 170614A, which was also detected by Fermi-GBM (trigger #519133191), INTEGRAL SPI-ACS (trigger #7869), Konus-Wind (trigger time on 11:39:55.892) and CALET (Takahashi et al, GCN 21255).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks emission with the strongest peak at 11:40:04.89 UT, ~21 s after the CALET Trigger. The measured peak count rate is 593.1 cts/s above the background in combined data of four quadrants, with a total of 5775 cts. The local mean background count rate was 369.9 cts/s. Using cumulative rates, we measure a T90 of 21.4 s.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

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: GRB170616A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21257
SUBJECT: IPN Triangulation of GRB 170616A (short/hard)
DATE:    17/06/19 18:56:30 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,

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, hard-spectrum GRB 170616A was detected by
Konus-Wind, Mars-Odyssey (HEND), and INTEGRAL (SPI-ACS),
at about 57987 s UT (16:06:27).

We have triangulated it to a preliminary, 3 sigma error box whose 
coordinates are:
---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
   113.437 (07h 33m 45s)  -2.244 ( -2d 14' 37")
  Corners:
   114.982 (07h 39m 56s)  -1.242 ( -1d 14' 32")
   114.689 (07h 38m 45s)  -1.669 ( -1d 40' 08")
   111.834 (07h 27m 20s)  -3.158 ( -3d 09' 28")
   112.167 (07h 28m 40s)  -2.763 ( -2d 45' 46")
  ---------------------------------------------
The error box area is 2500 sq. arcmin, and its maximum
dimension is 3.68 deg (the minimum one is 13 arcmin).
The Sun distance was 37 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB170616_T57991/IPN

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


GRB_name: GRB170616A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21258
SUBJECT: Konus-Wind observation of GRB 170616A
DATE:    17/06/19 19:08:27 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 GRB 170616A
(IPN triangulation: Hurley et al., GCN Circ. 21257)
triggered Konus-Wind at T0=57991.385 s UT (16:06:31.385).

The burst light curve shows a single pulse
which starts at ~T0-16 ms and has a total duration of ~42 ms.
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/GRB170616_T57991/

As observed by Konus-Wind, the burst
had a fluence of 3.39(-1.05,+1.14)x10^-6 erg/cm2,
and a 16-ms peak flux, measured from T0-0.014 s,
of 1.14(-0.52,+0.56)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+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 = -0.69(-0.31,+0.42)
and Ep = 2.5(-1.2,+2.7) MeV (chi2 = 5/7 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -1.5
(chi2 = 5/6 dof).

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


GRB_name: GRB170607A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21259
SUBJECT: GRB 170607A CALET Gamma-Ray Burst Monitor detection
DATE:    17/06/20 00:40:51 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

S. Nakahira (RIKEN), A. Yoshida, T. Sakamoto, Y. Kawakubo,
M. Moriyama, Y. Yamada, A. Tezuka, S. Matsukawa (AGU),
K. Yamaoka (Nagoya U), 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),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long-duration GRB 170607A (D'Ai et al., GCN Circ. 21214;
Hamburg et al., GCN Circ. 21218; INTEGRAL SPI-ACS trigger #7864)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 23:17:56.98
on 7 June 2017.  The burst signal was seen only by the SGM instrument.

The light curve of the SGM shows two distinct peaks.  The first
peak starts at T+2 sec, peaks at T+4 sec and ends at T+8 sec.
The second peak starts at T+210 sec, peaks at T+215 sec and
ends at T+230 sec.  The T90 durations of the first peak and the
second peak measured by the SGM data separately are 4.0 +- 0.5 sec
and 10.5 +- 0.8 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1180912206/

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


GRB_name: GRB170626A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21264
SUBJECT: GRB 170626A: Swift detection of a burst
DATE:    17/06/26 09:53:22 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

F. E. Marshall (NASA/GSFC), A. P. Beardmore (U Leicester),
A. A. Breeveld (UCL-MSSL), D. N. Burrows (PSU),
S. W. K Emery (UCL-MSSL), P. A. Evans (U Leicester),
N. P. M. Kuin (UCL-MSSL), K. L. Page (U Leicester),
D. M. Palmer (LANL) and B. Sbarufatti (INAF-OAB/PSU) report on behalf
of the Swift Team:

At 09:37:23 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 170626A (trigger=758766).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 165.414, +56.469 which is 
   RA(J2000) = 11h 01m 39s
   Dec(J2000) = +56d 28' 09"
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 15 sec.  The peak count rate
was ~35000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 09:38:21.6 UT, 58.5 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 165.3927, 56.4759 which is equivalent to:
   RA(J2000)  = +11h 01m 34.25s
   Dec(J2000) = +56d 28' 33.2"
with an uncertainty of 5.3 arcseconds (radius, 90% containment). This
location is 49 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy. 

The initial flux in the 2.5 s image was 1.52e-09 erg cm^-2 s^-1 (0.2-10
keV). 

The XRT position is 5.4 arcmin away from a magnitude 2 star (Merak),
therefore there are no UVOT data for this burst. 

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: GRB170626B
Detection_method: Insight-HXMT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21265
SUBJECT: GRB 170626B: The first GRB detected by the Insight-HXMT X-ray Telescope (revised)
DATE:    17/06/26 16:16:06 GMT    (revised submission 17/06/27 05:32:06 UT)
FROM:    Shaolin Xiong at IHEP  <xiongsl@ihep.ac.cn>

C. Z. Liu, X. Ma, J. Y. Liao, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu,
J. L. Zhao, A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin,
Z. Zhang (THU), X. B. Li, S. L. Xiong, C. K. Li, Y. Huang, Y. P. Chen,
M. Y. Ge, M. Gao (IHEP), T. P. Li (IHEP/THU), G. Li, M. S. Li, H. W. Liu,
F. J. Lu, L. M. Song, W. H. Tao, H. Y. Wang, Y. H. Wang, X. Y. Wen,
M. Wu, H. Xu, Y. P. Xu, C. M. Zhang, F. Zhang, J. Zhang, T. Zhang,
S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team:

The Insight-HXMT (Hard X-ray Modulation Telescope) satellite,
was launched successfully on June 15, 2017. As one of the three
instruments onboard the Insight-HXMT, the High Energy x-ray telescope (HE)
consists of 18 detector modules with a total area of about 5000 cm2.
Each HE module is made of a NaI(Tl)/CsI(Na) PHOSWICH detector.
The CsI detectors can work as a GRB monitor in the energy range of 40 keV
to ~1000 keV in the normal operation mode, or 200 keV to ~3 MeV in the
GRB operation mode, with a large effective area up to about 2000 cm2
on average and a FoV covering nearly the whole sky unblocked by the Earth.

During the commissioning phase, at 2017-06-26T00:57:55.800 (T0),
Insight-HXMT detected the GRB 170626B (trig ID: HEB170626040)
in a routine search of the data, which was also observed by the CALET
(trig# 1182473374) and the Konus-Wind (trig time: 2017-06-26T00:58:02.21).

After comparing the measurements with CALET and Konus-Wind,
we conclude that this is the first confirmed GRB discovered by
the Insight-HXMT Telescope!

The Insight-HXMT light curve mainly consists of two pulses
with a duration (T90) of 6.5 s measured from T0+1.26 s.
The 1-second peak rate, measured from T0+5.0 s, is 4624.5 cnts/sec.
The total counts from this burst is 13919 counts.
All measurements above are made with the CsI detectors in the energy range
of about 80-840 keV. Please note that this is the deposited energy,
rather than the incident photon energy.

URL_LC: http://www.hxmt.org/images/GRB/HEB170626040_lc.jpg

The Insight localization of this GRB gives (J2000):
RA:     241.69   [deg]
DEC:    -54.13   [deg]
Err:     10  [deg]

The statistical error is about 2 deg, however, the systematic error should
dominate at the commissioning phase since the calibration is sill ongoing.
We estimate the total error of location is about 10 deg, as indicated with
the red circle in the following location map.

URL_LOC: http://www.hxmt.org/images/GRB/HEB170626040_loc.jpg

The analysis results presented above are preliminary;
final results will be published elsewhere.

Insight-HXMT is the first Chinese space X-ray telescope, which was funded
jointly by the China National Space Administration (CNSA) and
the Chinese Academy of Sciences (CAS).
More information about this telescope could be found at:
http://www.hxmt.org/index.php/enhome .

[GCN OPS NOTE(27jun17):  Per author's request, this is a revised version
of the original GCN 21265 circular.  The "localization" and "statistical error"
paragraphs were added.]

///////////////////////////Original Distribution///////////////////////
TITLE:   GCN CIRCULAR
NUMBER:  21265
SUBJECT: GRB 170626B: The first GRB detected by the Insight-HXMT X-ray Telescope
DATE:    17/06/26 16:16:06 GMT
FROM:    Shaolin Xiong at IHEP  <xiongsl@ihep.ac.cn>

C. Z. Liu, X. Ma, J. Y. Liao, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu,
J. L. Zhao, A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin,
Z. Zhang (THU), X. B. Li, S. L. Xiong, C. K. Li, Y. Huang, Y. P. Chen,
M. Y. Ge, M. Gao (IHEP), T. P. Li (IHEP/THU), G. Li, M. S. Li, H. W. Liu,
F. J. Lu, L. M. Song, W. H. Tao, H. Y. Wang, Y. H. Wang, X. Y. Wen,
M. Wu, H. Xu, Y. P. Xu, C. M. Zhang, F. Zhang, J. Zhang, T. Zhang,
S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team:

The Insight-HXMT (Hard X-ray Modulation Telescope) satellite,
was launched successfully on June 15, 2017. As one of the three
instruments onboard the Insight-HXMT, the High Energy x-ray telescope (HE)
consists of 18 detector modules with a total area of about 5000 cm2.
Each HE module is made of a NaI(Tl)/CsI(Na) PHOSWICH detector.
The CsI detectors can work as a GRB monitor in the energy range of 40 keV
to ~1000 keV in the normal operation mode, or 200 keV to ~3 MeV in the
GRB operation mode, with a large effective area up to about 2000 cm2
on average and a FoV covering nearly the whole sky unblocked by the Earth.

During the commissioning phase, at 2017-06-26T00:57:55.816 (T0),
Insight-HXMT detected the GRB 170626B (trig ID: HEB170626040)
in a routine search of the data, which was also observed by the CALET
(trig# 1182473374) and the Konus-Wind (trig time: 2017-06-26T00:58:02.21).

After comparing the measurements with CALET and Konus-Wind,
we conclude that this is the first confirmed GRB discovered by
the Insight-HXMT Telescope!

The Insight-HXMT light curve mainly consists of two pulses
with a duration (T90) of 6.3 s measured from T0+2.51 s.
The 1-second peak rate, measured from T0+6.5 s, is 4426.9 cnts/sec.
The total counts from this burst is 13784 counts.
All measurements above are made with the CsI detectors in the energy range
of about 80-840 keV. Please note that this is the deposited energy,
rather than the incident photon energy.

URL_LC: http://newshxmt.ihep.ac.cn/images/GRB/HEB170626040_lc.jpg

The analysis results presented above are preliminary;
final results will be published elsewhere.

Insight-HXMT is the first Chinese space X-ray telescope, which was funded
jointly by the China National Space Administration (CNSA) and
the Chinese Academy of Sciences (CAS).
More information about this telescope could be found at:
http://newshxmt.ihep.ac.cn/index.php/enhome .


GRB_name: GRB170626A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21266
SUBJECT: GRB 170626A: Fermi GBM observation
DATE:    17/06/26 19:12:51 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007@uah.edu>

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

"At 09:37:21.95 UT on 26 June 2017, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 170626A (trigger 520162646 / 170626401)
which was also detected by the Swift/BAT
(Marshall et al. 2017, GCN 21264).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 75
degrees.

The GBM light curve shows one main peak
with a duration (T90) of about 12 s (50-300 keV).
The time-averaged spectrum from T0+0.00 to T0+13.6 s is
best fit by a Band function with Epeak = 94 +/- 2 keV,
alpha = -0.74 +/- 0.03, and beta = -2.7 +/- 0.1.

The event fluence (10-1000 keV) in this time interval is
(1.57 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.09 s in the 10-1000 keV band
is 37.2 +/- 0.5 ph/s/cm^2.

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


GRB_name: GRB170626A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21267
SUBJECT: GRB 170626A: Swift-XRT refined Analysis
DATE:    17/06/26 20:01:54 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. Cholden-Brown (PSU), P.A. Evans (U. Leicester), S.L. Gibson (U.
Leicester), J.P. Osborne (U. Leicester), A. Melandri (INAF-OAB), P.
D'Avanzo (INAF-OAB), V. D'Elia (ASDC), S. J. LaPorte (PSU), J.A. Kennea
(PSU) and F.E. Marshall report on behalf of the Swift-XRT team:

We have analysed 9.4 ks of XRT data for GRB 170626A (Marshall et al.
GCN Circ. 21264), from 51 s to 28.8 ks after the  BAT trigger. The data
comprise 1.2 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 refined XRT position is RA, Dec = 165.3936, +56.4768 which is
equivalent to:

RA (J2000): 11 01 34.46
Dec(J2000): +56 28 36.5

with an uncertainty of 3.5 arcsec (radius, 90% confidence).

The late-time light curve (from T0+5.4 ks) can be modelled with a
power-law decay with a decay index of alpha=1.22 (+/-0.09).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.019 (+/-0.025). The
best-fitting absorption column is  3.2 (+/-0.5) x 10^20 cm^-2, in
excess of the Galactic value of 6.7 x 10^19 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.73 (+/-0.08) and a
best-fitting absorption column of 3.2 (+1.8, -1.7) x 10^20 cm^-2. The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 3.7 x 10^-11 (3.9 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      3.2 (+1.8, -1.7) x 10^20 cm^-2
Galactic foreground: 6.7 x 10^19 cm^-2
Excess significance: 2.4 sigma
Photon index:      1.73 (+/-0.08)

If the light curve continues to decay with a power-law decay index of
1.22, the count rate at T+24 hours will be 0.039 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.4 x
10^-12 (1.5 x 10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00758766.

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


GRB_name: GRB170626A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21268
SUBJECT: GRB 170626A: SAO RAS possible OT detection
DATE:    17/06/26 21:46:26 GMT
FROM:    Moskvitin Alexander at SAO RAS  <mosk@sao.ru>

A. S. Moskvitin report on behalf of larger GRB follow-up team:

We observed the field of the GRB 170626A (Marshall et al., GCNC 21264)
with the 1-m telescope of SAO RAS, Zeiss-1000 on June, 26.
The observations started at 19:57:42 UT.
We obtained several images in Rc band and detected possible OT within
the refined XRT error box (Cholden-Brown et al., GCNC 21267).

The coordinates of object are:
R. A. (2000) =  11:01:34.0
Decl. (2000) = +56:28:35.3
the error is about 0.5".

Preliminary photometry of the object: R = 19.7 +/- 0.2,
T - T0 = 10.575 hours (calibration was done by the nearby SDSS stars,
and Lupton 2005 transformation equations).
Due to absence of the observed object at SDSS we can suggest
that it can be GRB OT.


GRB_name: GRB170626A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21269
SUBJECT: GRB 170626A: Afterglow detection from 1.5m OSN 
DATE:    17/06/26 22:27:03 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), and F. Aceituno,
D.A. Kann, L. Izzo, C. Thoene (IAA-CSIC) report on behalf of 
a larger collaboration:

We observed the field of GRB 170626A (Marshal et al. GCN 21264)
with the 1.5m OSN telescope in Sierra Nevada Observatory (Granada,
Spain). Observation consisted of a series of 240 s R-band exposures,
starting at 20:56:49 UT (11.32 hr after the burst). The afterglow is well 
detected at a position consistent with the one reported by Moskvitin et 
al. (GCN 21268), (J2000, +/-0.5â€):

R.A.: 11:01:34.09
Dec.: +56:28:35.4

In the combination of the first 12x240s exposures we measure a 
magnitude of R(AB) = 20.6+/- 0.2 as compared to SDSS stars.


GRB_name: GRB170626A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21270
SUBJECT: GRB 170626A: TNG optical observations
DATE:    17/06/26 22:28:12 GMT
FROM:    Andrea Melandri at INAF-OAB  <andrea.melandri@brera.inaf.it>

A. Melandri, P. D'Avanzo (INAF-OAB), V. D'Elia (INAF/OAR & ASI/ASDC), D. Carosati, G. Andreuzzi (INAF-TNG) report on behalf of the CIBO collaboration: 

We observed the field of GRB 170626A (Marshall et al., GCN Circ. 21264; Hamburg & Meegan, GCN Circ. 21266) with the 3.6m Telescopio Nazionale Galileo (TNG) equipped with DOLoRes. Observations were carried out in the r-sdss filter. Observations started on Jun 26 at 21:07:35 UT (~11.53 hours after the burst) and consist in a single image lasting 180 seconds.

At the edge of the refined XRT position (Cholden-Brown et al., GCN Circ. 21267) we detect a candidate optical afterglow at the following coordinates: RA(J2000) = 11:01:34.04, Dec(J2000) = +56:28:35.0, with an uncertainty of 0.5". This position is in agreement with the one reported by Moskvitin (GCN Circ. 21268).

The optical afterglow is detected with a magnitude r(AB) = 20.2 +/- 0.2 (calibrated against nearby stars reported in the PAN-STARSS catalogue).


GRB_name: GRB170626A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21271
SUBJECT: GRB 170626A: Swift-BAT refined analysis
DATE:    17/06/27 01:57:25 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

S. D. Barthelmy (GSFC), J. R. Cummings (CPI),
H. A. Krimm (NSF/USRA), 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 the recent telemetry downlink,
we report further analysis of BAT GRB 170626A (trigger #758766)
(Marshall et al., GCN Circ. 21264).  The BAT ground-calculated position is
RA, Dec = 165.409, 56.479 deg which is
  RA(J2000)  =  11h 01m 38.1s
  Dec(J2000) = +56d 28' 45.4"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 96%.

The mask-weighted light curve shows a multi-peaked structure. The main
emission starts at ~ T-1 s, peaks at ~T0, and ends at ~T+12 s. In addition,
there are some weak emissions that start prior to the main pulse at ~T-20 s,
and another weak pulse at ~T+80 s. T90 (15-350 keV) is 12.94 +- 0.34 sec
(estimated error including systematics).

The time-averaged spectrum from T-21.34 to T+17.92 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 1.26 +- 0.14,
and Epeak of 120.9 +- 31.0 keV (chi squared 51.05 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 8.2 +- 0.2 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T-0.06 sec in the 15-150 keV band is
23.6 +- 0.6 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.60 +- 0.03 (chi squared 69.77 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/758766/BA/


GRB_name: GRB170626A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21272
SUBJECT: GRB 170626A: MASTER-Tunka OT detection. 
DATE:    17/06/27 13:49:43 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

O.Gres, N.M.Budnev, O.Ershova
Irkutsk State University

V. Lipunov, E.Gorbovskoy, N.Tyurina, V.Kornilov,  A.Kuznetsov, V.Vladimirov, 
I.Gorbunov, D.Kuvshinov,  A.V.Krylov, P.Balanutsa, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University, Sternberg Astronomical Institut of MSU

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

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

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

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

R.Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA),
National University of San Juan, Argentina

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

MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in Tunka was starting inspection on the Swift  GRB 170626A 
error-box (ra=11 01 34 dec=+56 28 36 r=0.05)  22799 sec after notice time and 24464 
sec after trigger time at 2017-06-26 16:45:56 UT. The 5-sigma upper limit 
on our added image (3x180s exposure)  set is about 19.8  mag .

We see OT with unfiltered magnitude 19.8 +0.2/-0.3 mag at Moskvitin et 
al. (GCN #21268) position (see also A. de Ugarte Postigo et al.,GCN 
#21269; Melandri et al., GCN #21270; ).


The message may be cited.


GRB_name: GRB170626A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21273
SUBJECT: GRB 170626A: OASDG optical observations
DATE:    17/06/27 14:15:22 GMT
FROM:    Luca Izzo at IAA-CSIC  <Luca.Izzo@ICRA.it>

L. Izzo (IAA-CSIC), L. D'Avino, A. Noschese, M. Mollica, L. Morrone, N. Ruocco, A. Vecchione (AC-OASDG) report:

We observed the field of GRB 170626A (Marshall et al. GCN 21264) with the 0.5m telescope of the Osservatorio Astronomico S. Di Giacomo located in Agerola, Italy ( http://acgo.it/oa ).  
We obtained a series of 18x180 s images in the Rc filter, starting at 20:48:16 UT, ~ 11.2 hrs after the GRB trigger. We detect the GRB afterglow (Moskvitin GCN 21268, de Ugarte Postigo et al. GCN 21269, Melandri et al. GCN 21270, Lipunov et al. GCN 21272) and measure a magnitude of R(AB) = 20.1 +- 0.5. 

An image of the field can be seen at http://acgo.it/grb26a


GRB_name: GRB170626A
Detection_method: Insight-HXMT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21274
SUBJECT: GRB 170626A: Insight-HXMT observation
DATE:    17/06/27 15:29:39 GMT
FROM:    Shaolin Xiong at IHEP  <xiongsl@ihep.ac.cn>

Y. P. Xu, M. Y. Ge, S. L. Xiong, C. Z. Liu, X. F. Li, Z. W. Li,
J. Y. Liao, X. B. Li, C. K. Li, Y. Huang, Z. Chang, X. F. Lu,
J. L. Zhao, A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin,
Z. Zhang (THU), Y. P. Chen, M. Gao (IHEP), T. P. Li (IHEP/THU),
G. Li, M. S. Li, H. W. Liu, F. J. Lu, L. M. Song, W. H. Tao, H. Y. Wang,
Y. H. Wang, X. Y. Wen, M. Wu, H. Xu, C. M. Zhang, F. Zhang, J. Zhang,
T. Zhang, S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team:

During the commissioning phase, at 2017-06-26T09:37:22.32 (T0),
Insight-HXMT detected GRB 170626A (trigger ID: HEB170626400)
in a routine search of the data, which was also observed by the Swift/BAT
(Marshall et al. 2017, GCN 21264) and the Fermi/GBM
(Hamburg et al. 2017, GCN 21266).

The Insight-HXMT light curve mainly consists of several pulses
with a duration (T90) of 12.1 s measured from T0-0.43 s.
The 1-second peak rate, measured from T0+0.5 s, is 3275.0 cnts/sec.
The total counts from this burst is 9887 counts.
All measurements above are made with the CsI detectors in the energy range
of about 80-840 keV. Please note that this is the deposited energy,
rather than the incident photon energy.

URL_LC: http://www.hxmt.org/images/GRB/HEB170626400_lc.jpg

The time-averaged spectrum from T0-2.5s to T0+12.5 s is
adequately fit by a Power Law model with spectral index = -1.85 +/- 0.03.
The event fluence (200 -50000 keV) in this time interval is
(1.86 +/- 0.09)E-05 erg/cm^2.

The analysis results presented above are preliminary;
final results will be published elsewhere.

Insight-HXMT is the first Chinese space X-ray telescope, which was funded
jointly by the China National Space Administration (CNSA) and
the Chinese Academy of Sciences (CAS).
More information about this telescope could be found at:
http://www.hxmt.org/index.php/enhome .


GRB_name: GRB170607A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21275
SUBJECT: GRB 170607A: 15 GHz upper limits from AMI
DATE:    17/06/27 15:37:54 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 
170607A (D'Ai et al., GCN 21214) 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 Jun 08.12, Jun 10.29, Jun 
12.28 and Jun 16.24 (UT) do not reveal any radio source at the XRT 
location (Beardmore et al., GCN 21215), with 3sigma upper limits of 318 
uJy, 108 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: GRB170626A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21276
SUBJECT: GRB 170626A: TShAO  optical observations
DATE:    17/06/27 16:50:15 GMT
FROM:    Alexei Pozanenko at IKI  <alex@grb.rssi.ru>

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

We observed the field of the Swift GRB 170626A (Marshall et al., GCN Circ. 21264; Hamburg & Meegan, GCN Circ. 21266) with Zeiss-1000 1-m telescope of Tien Shan Astronomical Observatory starting on May 20 (UT) 18:42:38. We took several images in R-filter with total exposure of 1130 s.  The optical afterglow (Moskvitin et al., GCN 21268; de Ugarte Postigo, et al., GCN 21269) is clearly visible in a stacked image.

Preliminary photometry of the afterglow is following:

Date       UT start   t-T0    Filter Exp. OT     Err. UL     
                     (mid, days)     (s)             (3 sigma)

2016-06-26 16:47:33  0.30832  R    1130   19.87  0.13 21.0  

The magnitude is also compatible with a magnitude of the afterglow reported by Lipunov (GCN 21272) after observation at the same epoch.
Taken into account that between our observation at ~7.4 hours (mid time) and TNG observation at 11.53 hours (Melandri et al., GCN 21270) the magnitude of the aftegrlow did not change one may suggest either flare like activity or plateau phase of the afterglow and the burst can interesting for follow up observations.

The  finding chart can be found at http://grb.rssi.ru/GRB170626A/GRB170626a-fc_TShAO.png

The photometry is based on nearby SDSS stars, part of them already used in Moskvitin et al. (GCN 21169).

SDSS_id              R_Lupton Err
J110107.23 +564104.2 15.987 0.013
J110157.37 +563628.5 15.225 0.013
J110211.15 +563624.1 15.177 0.012
J110206.51 +563744.1 14.808 0.012
J110111.46 +563755.3 15.480 0.012
(GCN 21169)
J110106.88 +563153.7 16.389 0.013
J110125.73 +563134.0 18.332 0.023
J110124.28 +563251.1 17.839 0.017


GRB_name: GRB170626A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21277
SUBJECT: GRB 170626A: SAO RAS confirmation of OT fading
DATE:    17/06/27 22:58:52 GMT
FROM:    Moskvitin Alexander at SAO RAS  <mosk@sao.ru>

A. Moskvitin (SAO RAS), A. Volnova (IKI RAS), A. Pozanenko (IKI RAS),
I. Reva (Fesenkov Astrophysical Institute),
report on behalf of larger GRB follow-up team:

We observed the field of the GRB 170626A (Marshall et al., GCNC 21264)
with the 1-m telescope of SAO RAS, Zeiss-1000 on June, 27.
The OT observed by numerous telescopes (de Ugarte Postigo et al.,
GCNC 21269; Melandri et al., GCNC 21270; Gres et al. GCNC 21272;
Izzo et al., GCNC 21273; Volnova et al., GCNC 21276)
is approx. 0.9 magnitude fainer than in previous SAO epoch.
F ~ (t-T0)^ alpha. The decay slope alpha is about -0.7.
ftp://ftp.sao.ru/pub/grb/GRB170626A/GRB170626A_2epochs.png

The result of the first SAO epoch (GCNC 21268) were checked with the
full 1.5 hour stack obtained during the first night.
The stacked frames of both epochs were re-calibrated
against all standards mentioned by Volnova et al. (GCNC 21276).
The results are presented in the following table.
The errors are statistical only.


Date       UT start   T_mid - T0, d  Filter Exp., s   mag_OT   Err.

2016.06.26 19:57:42   0.4695         Rc     18 x 300  19.83 +/- 0.04 (GCNC
21268)
2016.06.27 18:50:27   1.4079         Rc     12 x 300  20.68 +/- 0.07


GRB_name: GRB170626A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21278
SUBJECT: Konus-Wind observation of GRB 170626A
DATE:    17/06/28 12:47:29 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 GRB 170626A (Swift-BAT trigger #758766:
Marshall et al., GCN 21264; Barthelmy et al., GCN 21271;
Fermi GBM observation: Hamburg et al., GCN 21266;
Insight-HXMT observation: Xu et al., GCN 21274)
triggered Konus-Wind at T0=34640.048 s UT (09:37:20.048).

The burst light curve shows a multipeaked structure
started at ~T0-0.4 s with a total duration of ~12.8 s.
The emission is seen up to ~10 MeV.

As observed by Konus-Wind, the burst
had a fluence of 1.22(-0.05,+0.05)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+0.576 s,
of 6.70(-0.97,+0.98)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+15.360 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 = -1.23(-0.10,+0.11)
and Ep = 110(-7,+8) keV (chi2 = 92/99 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
the high energy photon index beta = -3.3 (-0.9,+0.4)
(chi2 = 90/98 dof)

The spectrum near the maximum count rate
(measured from T0+0.256 to T0+7.168 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model
with  alpha = -1.17(-0.10,+0.11)
and Ep = 123(-8,+9) keV (chi2 = 78/95 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
the high energy photon index beta = -3.5 (-3.1,+0.4)
(chi2 = 77/94 dof)

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB170626_T34640/

All the quoted errors are at the 90% confidence level,
except for beta errors, which are at the 68% confidence level.
All the quoted values are preliminary.


GRB_name: GRB170626B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21279
SUBJECT: IPN Triangulation of GRB  170626B
DATE:    17/06/28 14:16:58 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

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

K. Hurley, on behalf of the IPN,

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

The long-duration GRB 170626B was detected by Insight (HXMT),
Konus-Wind, CALET (CGBM), and Swift (BAT) at about 3482 s UT (00:58:02).
The burst was outside the coded field of view of the BAT.

We have triangulated it to a Konus-BAT annulus centered at
RA(2000)=289.789 deg (19h 19m 09s)  Dec(2000)=-19.171 deg (-19d 10' 15"),
whose radius is 4.975 Â± 4.975 deg (3 sigma).

This annulus is inconsistent with the HXMT position reported
by Liu et al. (GCN 21265); also, the KW ecliptic latitude response
implies the source position close to the ecliptic plane, which
is ~30 deg from the HXMT localization.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB170626_T03482/IPN/

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


GRB_name: GRB170626B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21280
SUBJECT: Konus-Wind observation of GRB 170626B
DATE:    17/06/28 14:20:04 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 GRB 170626B
(Insight-HXMT observation: Liu et al., GCN 21265;
IPN triangulation: Kozlova et al., GCN 21279)
triggered Konus-Wind at T0=3482.215 s UT (00:58:02.215).

The burst light curve shows a multipeaked structure
started at ~T0-6.1 s with a total duration of ~16.8 s.
The emission is seen up to ~10 MeV.

As observed by Konus-Wind, the burst
had a fluence of 4.12(-0.20,+0.22)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+4.256 s,
of 1.03(-0.18,+0.18)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+14.592 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(-0.13,+0.14)
and Ep = 423(-38,+45) keV (chi2 = 87/99 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 = 87/98 dof)

The spectrum near the maximum count rate
(measured from T0+0.256 to T0+6.400 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model
with  alpha = -0.45(-0.11,+0.12)
and Ep = 429(-30,+35) keV (chi2 = 91/92 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.8
(chi2 = 91/91 dof)

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB170626_T03482/

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


GRB_name: GRB170626B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21282
SUBJECT: GRB 170626B CALET Gamma-Ray Burst Monitor detection
DATE:    17/06/29 06:12:38 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

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

The long-duration GRB 170626B (Liu et al., GCN Circ. 21265; Konus-Wind
trigger time on 00:58:02.21 UT) triggered the CALET Gamma-ray Burst
Monitor (CGBM) at 00:57:56.28 on 26 June 2017.  The burst signal was
seen by the all CGBM instruments.

The light curve of the SGM shows two overlapping peaks.  The emission
starts at T+1 sec, peaks at T+2.5 sec (the first peak) and T+5.5 sec
(the second peak), and ends at T+10 sec.  The T90 duration measured by
the SGM data is 5.0 +- 0.4 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1182473374/

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


GRB_name: GRB170629A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21283
SUBJECT: GRB 170629A: Swift detection of a burst
DATE:    17/06/29 13:22:45 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

A. Cholden-Brown (PSU), A. A. Breeveld (UCL-MSSL),
S. W. K Emery (UCL-MSSL), J. A. Kennea (PSU),
N. P. M. Kuin (UCL-MSSL), A. Y. Lien (GSFC/UMBC),
P. T. O'Brien (U Leicester), K. L. Page (U Leicester),
D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and
M. H. Siegel (PSU) report on behalf of the Swift Team:

At 12:53:33 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 170629A (trigger=759159).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 130.016, -46.587 which is 
   RA(J2000) = 08h 40m 04s
   Dec(J2000) = -46d 35' 11"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve is incomplete at this
time due to lost telemetry, but was still rising at 8 sec after 
the trigger with a count rate of ~1500 counts/sec. 

The XRT began observing the field at 12:54:56.0 UT, 82.9 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 129.98653, -46.57155 which
is equivalent to:
   RA(J2000)  = 08h 39m 56.77s
   Dec(J2000) = -46d 34' 17.6"
with an uncertainty of 4.7 arcseconds (radius, 90% containment). This
location is 91 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper.  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 5.16e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of  90 seconds with the UVW2 filter
 starting  86 seconds after the BAT trigger. No credible afterglow 
candidate has been  found in the initial data products. Analysis is
complicated because of a nearby bright star (b Vel). Full  results
will have to await the full dataset. 

Burst Advocate for this burst is A. Cholden-Brown (aaronb 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: GRB170629A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21285
SUBJECT: GRB 170629A: Fermi GBM observation
DATE:    17/06/29 22:03:09 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007@uah.edu>

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

"At 12:53:31.63 UT on 29 June 2017, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 170629A (trigger 520433616 / 170629537),
which was also detected by the Swift/BAT
(Cholden-Brown et al. 2017, GCN 21283).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 24
degrees.

The GBM light curve consists of a single emission episode
with a duration (T90) of about 28 s (50-300 keV).
The time-averaged spectrum from T0-0.00 s to T0+12.29 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 126 +/- 10 keV.

The event fluence (10-1000 keV) in this time interval is
(3.3 +/- 0.1)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+8.70 s in the 10-1000 keV band
is 6.0 +/- 0.3 ph/s/cm^2.

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


GRB_name: GRB170629A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21286
SUBJECT: GRB 170629A: Enhanced Swift-XRT position
DATE:    17/06/29 22:08:21 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 75 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 170629A, 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 = 129.98383, -46.57073 which is equivalent
to:

RA (J2000): 08h 39m 56.12s
Dec (J2000): -46d 34' 14.6"

with an uncertainty of 2.8 arcsec (radius, 90% confidence).

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

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


GRB_name: GRB170629A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21287
SUBJECT: GRB 170629A: Swift-BAT refined analysis
DATE:    17/06/30 12:57:07 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

J. R. Cummings (CPI), S. D. Barthelmy (GSFC),
A. Cholden-Brown (PSU), H. A. Krimm (NSF/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 170629A (trigger #759159)
(Cholden-Brown et al., GCN Circ. 21283).  The BAT ground-calculated position is
RA, Dec = 129.963, -46.585 deg which is 
  RA(J2000)  =  08h 39m 51.0s 
  Dec(J2000) = -46d 35' 06.3" 
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 17%.

The mask-weighted light curve shows a multi-peaked structure that starts 
at ~ T-1 s and ends at ~T+40 s. There are roughly two overlapping 
pulses with peaks at ~ T+1 s and ~ T+5 s, respectively.  The burst location 
went out of the FOV at around T+240 s. T90 (15-350 keV) is 34.4 +- 12.7 sec 
(estimated error including systematics).

The time-averaged spectrum from T-1.21 to T+39.32 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.66 +- 0.12.  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+4.96 sec in the 15-150 keV band
is 4.1 +- 0.6 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/759159/BA/


GRB_name: GRB170629A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21288
SUBJECT: GRB 170629A: Swift-XRT refined Analysis
DATE:    17/06/30 14:12:14 GMT
FROM:    Kim Page at U.of Leicester  <klp5@leicester.ac.uk>

A. Cholden-Brown (PSU) reports on behalf of the Swift-XRT team:

We have analysed 2.0 ks of XRT data for GRB 170629A (Cholden-Brown et
al. GCN Circ. 21283), from 97 s to 5.9 ks after the  BAT trigger. The
data comprise 140 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Evans et al. (GCN Circ. 21286).

The light curve can be modelled with a power-law decay with a decay
index of alpha=0.72 (+0.09, -0.12).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.8 (+0.6, -0.3). The
best-fitting absorption column is  1.11 (+0.79, -0.20) x 10^22 cm^-2,
consistent with the Galactic value of 9.1 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 5.3 x 10^-11 (8.5 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.11 (+0.79, -0.20) x 10^22 cm^-2
Galactic foreground: 9.1 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.8 (+0.6, -0.3)

If the light curve continues to decay with a power-law decay index of
0.72, the count rate at T+24 hours will be 0.014 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.2 x
10^-13 (1.2 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/00759159.

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


GRB_name: GRB170705A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21289
SUBJECT: GRB 170705A: Swift detection of a burst with an optical counterpart
DATE:    17/07/05 03:08:15 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

R. L. C. Starling (U Leicester), A. Cholden-Brown (PSU),
J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC),
F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester),
D. M. Palmer (LANL) and M. Stamatikos (OSU/NASA/GSFC) report on behalf
of the Swift Team:

At 02:45:47 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 170705A (trigger=760064).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 191.705, +18.293 which is 
   RA(J2000) = 12h 46m 49s
   Dec(J2000) = +18d 17' 35"
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 ~17000 counts/sec (15-350 keV), at ~13 sec after the trigger. 

The XRT began observing the field at 02:46:59.3 UT, 72.3 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 191.70472, 18.30811 which
is equivalent to:
   RA(J2000)  = 12h 46m 49.13s
   Dec(J2000) = +18d 18' 29.2"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 54 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (1.46 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 4.6
(+3.03/-2.52) x 10^21 cm^-2 (90% confidence). 

The initial flux in the 2.5 s image was 1.57e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 81 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 12:46:48.97 = 191.70406
  DEC(J2000) = +18:18:26.2  =  18.30727
with a 90%-confidence error radius of about 0.76 arc sec. This position is 3.7
arc sec. from the center of the XRT error circle. The estimated magnitude is
18.65 with a 1-sigma error of about  0.15. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.02. 

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: GRB170705A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21290
SUBJECT: GRB 170705A: Enhanced Swift-XRT position
DATE:    17/07/05 05:26:47 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 569 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 170705A, 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 = 191.70427, +18.30741 which is equivalent
to:

RA (J2000): 12h 46m 49.02s
Dec (J2000): +18d 18' 26.7"

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

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

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


GRB_name: GRB170705A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21291
SUBJECT: GRB 170705A: MASTER-OAFA  early OT observations 
DATE:    17/07/05 09:26:46 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, D.Kuvshinov, A.V.Krylov,
I.Gorbunov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University, Sternberg Astronomical Institut of MSU

R.Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA),
National University of San Juan, Argentina

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

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

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

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

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

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

MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in OAFA was pointed to the  GRB170705A (Starling et al.,GCN #21289)
24 sec after notice time  and 38 sec after trigger time at 2017-07-05 
02:46:27 UT  at high zenit distance.
On our first (10s  exposure)  unfiltered exposition we haven't found 
optical transient  within SWIFT error-box  (ra=191.704 dec=18.2928 r=0.05)
brighter than 15.0.


We marginally found OT at Swift UVOT position (Starling et al.,GCN #21289) 
on coaded image ID=79921 with m ~ 17.0.

  ID       DATE      UT     Exp      Type         Limit        Note

79817 2017-07-05 02:46:27  10    Alert (SWIFT)   15.0          no
79921 2017-07-05 02:46:27 190 SumAlert (SWIFT)   16.9 79817+79825+79820+79818 
79818 2017-07-05 02:47:20  20    Alert (SWIFT)   15.8         yes
79819 2017-07-05 02:48:24  30    Alert (SWIFT)   15.9          no
79820 2017-07-05 02:49:38  50    Alert (SWIFT)   16.2         yes
79822 2017-07-05 02:51:13  60    Alert (SWIFT)   16.3          no
79824 2017-07-05 02:52:57  90    Alert (SWIFT)   16.5          no
79825 2017-07-05 02:55:11 110    Alert (SWIFT)   16.4         yes
79826 2017-07-05 02:57:46 140    Alert (SWIFT)   16.4          no
79827 2017-07-05 03:00:48 180    Alert (SWIFT)   16.7          no
79829 2017-07-05 03:04:32 180    Alert (SWIFT)   16.3          no 
79830 2017-07-05 03:08:12 180    Alert (SWIFT)   16.0          no

The unfiltered magnitude is about ~17 m .
The big differences with UVOT magnitude may be connected with high GRB
redshift because our CCD is more red.

The observations made on zenit distance = 79 degrees, galaxy latitude b = 
81 degree. The moon (86 % bright part) is 66 degrees above the horizon. 
The distance between  moon and  object is 56
The sun  altitude  is -63.1 degree.
The object can be observed till 2017-07-05 03:46:20 .

The message may be cited.


GRB_name: GRB170705A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21292
SUBJECT: GRB 170705A: Swift-XRT refined Analysis
DATE:    17/07/05 10:34:21 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), S. J. LaPorte (PSU), J.A. Kennea (PSU), B. Sbarufatti
(INAF-OAB/PSU) and R.L.C. Starling report on behalf of the Swift-XRT
team:

We have analysed 8.4 ks of XRT data for GRB 170705A (Starling et al.
GCN Circ. 21289), from 62 s to 22.1 ks after the  BAT trigger. The data
comprise 424 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. 21290).

The late-time light curve (from T0+4.6 ks) can be modelled with a
power-law decay with a decay index of alpha=0.83 (+/-0.09).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.53 (+/-0.03). The
best-fitting absorption column is  8.4 (+1.1, -1.0) x 10^20 cm^-2, in
excess of the Galactic value of 1.5 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.87 (+0.09, -0.08)
and a best-fitting absorption column of 1.29 (+0.26, -0.24) x 10^21
cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.6 x 10^-11 (4.5 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.29 (+0.26, -0.24) x 10^21 cm^-2
Galactic foreground: 1.5 x 10^20 cm^-2
Excess significance: 7.7 sigma
Photon index:      1.87 (+0.09, -0.08)

If the light curve continues to decay with a power-law decay index of
0.83, the count rate at T+24 hours will be 0.11 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.0 x
10^-12 (5.0 x 10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00760064.

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


GRB_name: GRB170705A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21293
SUBJECT: GRB 170705A: RATIR Optical and NIR Observations
DATE:    17/07/05 14:58:02 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), JesÃºs
GonzÃ¡lez (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM), Harvey Moseley (GSFC), John
Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:

We observed the field of GRB 170705A (Starling, et al., GCN 21289) 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 2017/07 5.17 to 2017/07 5.26 UTC (1.34 to 3.41
hours after the BAT trigger), obtaining a total of 1.42 hours exposure in
the r and i bands and 0.59 hours exposure in the Z, Y, J, and H bands.

We detect the optical transient found by Swift and observed MASTER-OAFA
(Lipunov, et al., GCN 21291).  In comparison with the SDSS DR9 and 2MASS
catalogs, we obtain the following detections:

 r = 18.60 +/- 0.01
 i = 18.30 +/- 0.01
 Z = 18.03 +/- 0.01
 Y = 17.79 +/- 0.01
 J = 17.79 +/- 0.01
 H = 17.56 +/- 0.01

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.  The source fades as in time as
t^(-0.4) during our observation.

We note that the Swift-UVOT detection makes this GRB unlikely to be at very
high redshift.  Our photo-z calculations, using RATIR data alone, suggest
z<4.

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


GRB_name: GRB170705A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21294
SUBJECT: GRB 170705A: Swift/UVOT Detection
DATE:    17/07/05 15:08:53 GMT
FROM:    Sam Emery at MSSL-UCL  <samuel.emery.15@ucl.ac.uk>

S.W.K. Emery (UCL-MSSL) and R. L. C. Starling (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 170705A
82 s after the BAT trigger (Starling et al., GCN Circ. 21289).
We detect a fading source consistent with the XRT position
(Goad et al., GCN Circ. 21290) and the MASTER (Lipunov et al., GCN Circ. 21291)
and RATIR (Butler et al., GCN Circ. 21293) detections in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  12:46:48.97 = 191.70404 (deg.)
    Dec (J2000) = +18:18:26.4  =  18.30733 (deg.)
with an estimated uncertainty of 0.45 arc sec. (radius, 90% confidence).

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            82          231          147         18.55 +/- 0.06
white              573         1020          186         19.23 +/- 0.11
u                  294          543          246         19.43 +/- 0.19
v                  623         1070           58        >18.3
b                  549          741           39         18.92 +/- 0.26
uvw1               672          692           19        >18.1
uvm2              4617        12950          996        >20.7
uvw2              5644        11420         1137        >21.0

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: GRB170705A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21295
SUBJECT: GRB 170705A: MITSuME Akeno Optical Observation
DATE:    17/07/05 15:27:51 GMT
FROM:    Taketoshi Yoshii at Tokyo Tech  <yoshii.t.ac@m.titech.ac.jp>

S. Harita, Y. Saito, R. Itoh,  Y. Tachibana, T. Yoshii, 
K. Morita, T. Ozawa, H. Mamiya, K. Shiraishi, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:

We searched for the optical counterpart of GRB 170705A (R. L. C. Starling et al.,
GCN Circular #21289) with the optical three color (g', Rc, and Ic) CCD cameras 
attached to the MITSuME 50cm telescope of Akeno Observatory, Yamanashi, Japan.

The observation started on 2017-07-05 11:21:20.84 UT. 
We did not find any new point source within XRT circle in all three bands. 
We obtained following limits for the magnitudes.

T0+[hour]    MID-UT      T-EXP[sec]         g'              Rc                    Ic
-------------------------------------------------------------------------------------------------------
~8.59       12:29:51            1320          >18.5        >17.9                >17.8
-------------------------------------------------------------------------------------------------------

T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.


GRB_name: GRB170705A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21296
SUBJECT: GRB 170705A: Swift-BAT refined analysis
DATE:    17/07/05 16:14:33 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

H. A. Krimm (NSF/USRA), S. D. Barthelmy (GSFC), 
J. R. Cummings (CPI), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), 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 170705A (trigger #760064)
(Starling et al., GCN Circ. 21289).  The BAT ground-calculated position is
RA, Dec = 191.708, 18.298 deg which is 
  RA(J2000)  =  12h 46m 50.0s 
  Dec(J2000) = +18d 17' 51.3" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 83%.

The mask-weighted light curve shows a multi-peaked structure that starts
at ~ T0 and ends at ~ T+300 s. The main emission occurs at ~ T0 to ~ T+40 s, 
with the major peak at ~ T+14 s. T90 (15-350 keV) is 217.3 +- 18.0 sec 
(estimated error including systematics).

The time-averaged spectrum from T+0.44 to T+304.86 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.65 +- 0.05.  The fluence in the 15-150 keV band is 9.5 +- 0.3 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+13.41 sec in the 15-150 keV band
is 13.9 +- 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/760064/BA/

[GCN OPS NOTE(06jul17): Per author's request, the last paragaph was added.]


GRB_name: GRB170705A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21297
SUBJECT: GRB 170705A: Fermi GBM observation
DATE:    17/07/05 18:03:09 GMT
FROM:    Elisabetta Bissaldi at U.Innsbruk/IAPP  <Elisabetta.Bissaldi@uibk.ac.at>

E. Bissaldi (Politecnico & INFN Bari) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 02:45:51.03 UT on 5 July 2017, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 170705A (trigger 520915556 / 170705115),
which was also detected by the Swift/BAT (Starling et al. 2017, GCN 21289).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 118 
degrees.

The GBM light curve shows two peaks
with a duration (T90) of about 22 s (50-300 keV).
The time-averaged spectrum from T0-2 s to T0+20 s is
adequately fit by a Band function with Epeak = 100 +/- 10  keV,
alpha = -0.88 +/- 0.07, and beta = -2.38 +/- 0.09.

The event fluence (10-1000 keV) in this time interval is
(1.37 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+9.4 s in the 10-1000 keV band
is 22.5 +/- 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: GRB170705A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21298
SUBJECT: GRB 170705A: Redshift from 10.4m GTC/OSIRIS
DATE:    17/07/05 23:48:25 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), D.A. Kann (IAA-CSIC), 
L. Izzo (IAA-CSIC), C.C. Thoene (IAA-CSIC) report on behalf of the 
HETH group:

We observed the afterglow of GRB 170705A (Starling et al. GCN 21289, 
Lipunov et al. GCN 21291, Butler et al. GCN 21293, Emery et al. 
GCN 21294) with OSIRIS at the 10.4m GTC telescope. The observation 
consisted of 3x900s using grism R1000B, covering the range between 
3700 and 7880 AA at a mean epoch of July 5.9350 2017 UT (19.68 hr 
after the burst).

The acquisition shows the afterglow at a magnitude of r(AB) = 20.20 
+/- 0.10 mag, as compared to SDSS field stars. The spectrum shows 
continuum across all the spectral range, although the signal to noise 
ratio of the bluest part is low because of the bright sky due of the nearby 
almost full Moon. We detect weak spectral absorption features due to 
CIV, AlII, AlIII, FeII and FeII* at a common redshift of 2.010, which we 
identify as the redshift of the GRB.


GRB_name: GRB170705A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21299
SUBJECT: Konus-Wind observation of GRB 170705A
DATE:    17/07/06 11:16:24 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 170705A
(Swift-BAT observation: Starling et al., GCN Circ. 21289;
Fermi-GBM observation: Bissaldi and Meegan, GCN Circ. 21297)
triggered Konus-Wind at T0=9956.188 s UT (02:45:56.188).

The burst light curve shows a bright, multipeaked pulse,
which starts at ~T0-6 s and has a total duration of ~25 s,
followed by a weaker emission seen up to ~T0+300 s.
The emission in the main episode is seen up to ~1 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB170705_T09956/

As observed by Konus-Wind, the burst
had a fluence of 1.76(-0.19,+0.20)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+2.384 s,
of 4.21(-0.94,+0.96)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the main episode
(measured from T0 to T0+24.832 s)
is best fit in the 20 keV - 2 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -1.31(-0.17,+0.20)
and Ep = 155(-22,+31) keV (chi2 = 53/62 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.7
(chi2 = 59/61 dof).

The spectrum near the maximum count rate
(measured from T0+0.256 to T0+8.448 s)
is best fit in the 20 keV - 2 MeV range
by a power law with exponential cutoff model:
with  alpha = -1.16(-0.15,+0.16)
and Ep = 166(-18,+23) keV (chi2 = 69/61 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
(chi2 = 69/60 dof).

Assuming the redshift z=2.010 (de Ugarte Postigo et al.,
GCN Circ. 21298) and a standard cosmology model
with H_0 = 70 km/s/Mpc, Omega_M = 0.27, and Omega_Lambda = 0.73,
we estimate the following rest-frame parameters:
the isotropic energy release E_iso is ~1.8x10^53 erg,
the peak luminosity L_iso is ~1.3x10^53 erg/s,
and the rest-frame peak energy of the time-integrated spectrum,
Ep,i, is ~466 keV.

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


GRB_name: GRB170705A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21300
SUBJECT: GRB 170705A: ISON/Terskol optical observations
DATE:    17/07/06 13:28:01 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI), A. Pozanenko (IKI), V. Agletdinov (KIAM), A. Volnova 
(IKI),  A. Mokhnatkin (KIAM),   I. Molotov (KIAM)  report on behalf of 
larger GRB follow-up collaboration:

We observed the field of the Swift GRB 170705A (Starling et al. GCN 21289) 
which is also detected by GBM/Fermi and Konus-Wind  (Bissaldi  et al., GCN 
21297; Svinkini et al., GCN 21299) with K-800 (0.8m) telescope  of 
ISON/Terskol  observatory starting  on July, 05 (UT) 18:30:54.  We obtained 
several unfiltered images of 20 s exposure. The optical afterglow  of GRB 
170705A (Starling et al. GCN 21289, Lipunov et al. GCN 21291, Butler et al. 
GCN 21293, Emery et al. GCN 21294; Ugarte Postigo et al. GCN 21298)  is 
clearly visible in a combined image. Preliminary  photometry of the 
afterglow is following


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

2017-07-05  18:30:54 0.70649 CR      358*20 19.84 0.08 22.2


Photometry is based on nearby SDSS DR9 stars
SDSS id                          R_Lupton
J124702.82+181926.7 17.63
J124700.96+181851.9 19.15
J124653.35+182058.9 17.08
J124641.28+182043.7 16.61
J124646.57+181522.1 17.45
J124645.71+181510.4 17.18
J124650.58+182306.3 18.18
J124624.60+181820.0 16.34
J124647.75+181330.6 16.05
J124644.99+181414.3 18.79 


GRB_name: GRB170705A
Detection_method: Insight-HXMT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21301
SUBJECT: GRB 170705A: Insight-HXMT observation
DATE:    17/07/06 18:10:53 GMT
FROM:    Shaolin Xiong at IHEP  <xiongsl@ihep.ac.cn>

F. J. Lu, C. K. Li, S. L. Xiong, C. Z. Liu, X. F. Li, Z. W. Li,
X. B. Li, J. Y. Liao, Y. Huang, Y. H. Wang, Z. Chang, X. F. Lu,
J. L. Zhao, A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin,
Z. Zhang (THU), Y. P. Chen, M. Gao (IHEP), T. P. Li (IHEP/THU),
G. Li, M. S. Li, H. W. Liu, L. M. Song, W. H. Tao, H. Y. Wang,
X. Y. Wen, M. Wu, H. Xu, Y. P. Xu, C. M. Zhang, F. Zhang, J. Zhang,
T. Zhang, S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team:

During the commissioning phase, at 2017-07-05T02:45:59.00 (T0),
Insight-HXMT detected GRB 170705A (trigger ID: HEB170705115)
in a routine search of the data, which was also observed by
the Swift/BAT (Starling et al. 2017, GCN 21289), Fermi/GBM
(Bissaldi et al. 2017, GCN 20297) and Konus-Wind (Svinkin et al. 2017,
GCN 21299).

The Insight-HXMT light curve consists of single pulse
with a duration (T90) of 7.0 s measured from T0-1.30 s.
The 1-second peak rate, measured from T0+1 s, is 928.3 cnts/sec.
The total counts from this burst is 3458 counts.

All measurements above are made with the CsI detectors in the energy range
of about 80-840 keV (record energy) in the regular mode. Only gamma-rays 
with
energy greater than about 200 keV can penetrate the spacecraft and leave
signals in the CsI detectors installed on the inside of the telescope.

URL_LC: http://www.hxmt.org/images/GRB/HEB170705115_lc.jpg

The time-averaged spectrum from T0-2 s to T0+8 s is
adequately fit by a Power Law model with spectral index = -2.16 +/- 0.10.
The energy fluence is (1.42 +/- 0.30)E-05 erg/cm^2 in 200 - 5000 keV
in this time interval.

The analysis results presented above are preliminary;
final results will be published elsewhere.

Insight-HXMT is the first Chinese space X-ray telescope, which was funded
jointly by the China National Space Administration (CNSA) and the Chinese
Academy of Sciences (CAS). More information about it could be found at:
http://www.hxmt.org/index.php/enhome .


GRB_name: GRB170705A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21302
SUBJECT: GRB 170705A: KAIT Optical Observations
DATE:    17/07/06 18:23:52 GMT
FROM:    Max Genecov at UC Berkeley  <mgenecov@berkeley.edu>

Max Genecov, WeiKang Zheng, and Alex Filippenko (UC Berkeley) report on
behalf of the KAIT GRB team:


The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, responded to Swift GRB 170705A (Starling, et al.,GCN
21289), starting 1.66 hours after the burst and again 1.08
days after the burst. Observations were performed in the clear
(roughly R) filter, and the exposure time was 60 s per image.

The optical afterglow of GRB 170705A (Starling, et al.,GCN 21289;
Lipunov et al., GCN 21291; Butler et al. GCN 21293,
Emery et al. GCN 21294, Ugarte Postigo et al. GCN 21298, Pozenenko
et al. GCN 21300) was clearly detected in every single image from the
first night and in an image co-added from thirteen frames in the
second night. Preliminary photometry of the afterglow calibrated to
several nearby SDSS stars gives 18.1 +/- 0.2 mag at mean time
1.66 hours and 20.3 +/- 0.3 mag at mean time 1.08 days.


GRB_name: GRB170705A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21303
SUBJECT: GRB 170705A: Further RATIR Optical and NIR Observations and Steepening of Fading 
DATE:    17/07/06 18:37:15 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
(UVI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), JesÃºs GonzÃ¡lez (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM),
Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (ASU), and
Vicki Toy (UMD) report:

We observed the field of GRB 170705A (Starling et al., GCN Circ. 21289) 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 2017/07 6.17 to 2017/07 6.26 UTC (25.33
to 27.52 hours after the BAT trigger), obtaining a total of 1.02 hours
exposure in the r and i bands and 0.37 hours exposure in the Z,
Y, J, and H bands.

For a source within the Swift-XRT error circle, in comparison with the SDSS DR9 and 2MASS catalogs, we obtain the following detections:

 r = 20.62 +/- 0.05
 i = 20.35 +/- 0.05
 Z = 19.68 +/- 0.07
 Y = 19.72 +/- 0.09
 J = 19.46 +/- 0.10
 H = 19.61 +/- 0.16

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

The source has faded on average by 1.90 +/- 0.17 magnitudes compared to our previous observations (Butler et al., GCN Circ. 21293). This corresponds to a temporal index of -0.72 +/- 0.03, which is steeper than the index of -0.4 we saw during our previous observations.

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


GRB_name: GRB170708A
Detection_method: Insight-HXMT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21307
SUBJECT: GRB 170708A: Insight-HXMT detection
DATE:    17/07/09 12:55:01 GMT
FROM:    Shaolin Xiong at IHEP  <xiongsl@ihep.ac.cn>

S. L. Xiong, C. K. Li, J. Y. Liao, C. Z. Liu, X. F. Li, Z. W. Li,
Z. Chang, X. F. Lu, J. L. Zhao, A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP),
Y. J. Jin, Z. Zhang (THU), M. Gao (IHEP), T. P. Li (IHEP/THU), M. S. Li,
H. W. Liu, F. J. Lu, L. M. Song, W. H. Tao, H. Y. Wang, X. Y. Wen, M. Wu,
H. Xu, Y. P. Xu, C. M. Zhang, F. Zhang, J. Zhang, T. Zhang,
S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team:

During the commissioning phase, at 2017-07-08T01:06:11.25 (T0),
Insight-HXMT detected GRB 170708A (trigger ID: HEB170708045)
in a routine search of the data, which was also observed by the Fermi/GBM
(Trig# 521168776) and SPI-ACS (Trig time 2017-07-08T01:06:10.708).

The Insight-HXMT light curve consists of a single pulse
with a duration (T90) of 0.22 s measured from T0-0.05 s.
The 50-ms peak rate, measured from T0+0 s, is 3553.6 cnts/sec.
The total counts from this burst is 369 counts.

All measurements above are made with the CsI detectors operating in the
GRB mode, in which the energy range is increased to about 200 - 3000 keV
(record energy) , compared to the normal mode of 80 - 800 keV.
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the telescope.

URL_LC: http://www.hxmt.org/images/GRB/HEB170708045_lc.jpg

This is a weak short burst. The detection significance of Insight-HXMT
is ~10 sigma. The burst emission is seen up to ~1 MeV.

The analysis results presented above are preliminary;
final results will be published elsewhere.

Insight-HXMT is the first Chinese space X-ray telescope, which was funded
jointly by the China National Space Administration (CNSA) and the Chinese
Academy of Sciences (CAS). More information about it could be found at:
http://www.hxmt.org/index.php/enhome .


GRB_name: GRB170710A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21308
SUBJECT: GRB 170710A: Swift detection of a burst
DATE:    17/07/10 00:57:28 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

P. A. Evans (U Leicester), D. N. Burrows (PSU),
A. Cholden-Brown (PSU), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC),
F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester) and
D. M. Palmer (LANL) report on behalf of the Swift Team:

At 00:45:44 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 170710A (trigger=761119).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 231.812, -38.547 which is 
   RA(J2000) = 15h 27m 15s
   Dec(J2000) = -38d 32' 48"
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 10 sec.  The peak count rate
was ~800 counts/sec (15-350 keV), at ~2 sec after the trigger. 

The XRT began observing the field at 00:47:48.3 UT, 123.7 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 231.82076, -38.48434 which
is equivalent to:
   RA(J2000)  = 15h 27m 16.98s
   Dec(J2000) = -38d 29' 03.6"
with an uncertainty of 4.4 arcseconds (radius, 90% containment). This
location is 226 arcseconds from the BAT onboard position. 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 4.07e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 131 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.17. 

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: GRB170710A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21309
SUBJECT: GRB 170710A: Prompt enhanced Swift-XRT position
DATE:    17/07/10 01:33:45 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 170710A, we find an
enhanced XRT position of the afterglow: RA, Dec: 231.8199, -38.4852
which is equivalent to:
   RA (J2000)  = 15 27 16.77
   Dec (J2000) = -38 29 06.6
with an uncertainty of 2.3 arcseconds (radius, 90% confidence).
Analysis of the promptly available data is online at
http://www.swift.ac.uk/sper/761119.

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: GRB170710A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21310
SUBJECT: GRB 170710A: Enhanced Swift-XRT position
DATE:    17/07/10 06:58:48 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 3131 s of XRT Photon Counting mode data and 4 UVOT
images for GRB 170710A, 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 = 231.82030, -38.48496 which is equivalent
to:

RA (J2000): 15h 27m 16.87s
Dec (J2000): -38d 29' 05.8"

with an uncertainty of 1.9 arcsec (radius, 90% confidence).

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

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


GRB_name: GRB170710A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21311
SUBJECT: GRB 170710A: Gemini-S candidate counterpart
DATE:    17/07/10 11:04:40 GMT
FROM:    Antonino Cucchiara at UVI  <antonino.cucchiara@uvi.edu>

A. Cucchiara (U. of the Virgin Islands) reports on
behalf of a larger collaboration:

"On July 10.17UT we imaged the field of GRB 170710A
(Evans et al. GCN 21308, 21309, Osborne et al. GCN 21310)
with the Gemini-South Telescope equipped with the GMOS camera.
We obtained 4x900s spectra covering the 5660-10300 Angstrom
wavelength range.
In our single 180 seconds acquisition image in i' band centered
on the Swift-XRT position we identified an uncatalogued
point-like sources at the edge of the refined position:

RA= +15:27:16.87
Dec= -38:29:06.0

Using nearby USNO-B1 stars for calibration, we measure a
magnitude of i' = 21.13 +/- 0.05.
At this point it is not possible to assess the variability
of this possible counterpart.

Preliminary analysis of the spectra reveals a faint trace
clearly visible down to the blue end of the spectrum.
No clear absorption or emission features are evident,
but more detailed analysis of the data is in progress.

We thank the Gemini staff for the prompt response, in particular
Veronica Firpo."


GRB_name: GRB170710A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21312
SUBJECT: GRB 170710A: Swift-XRT refined Analysis
DATE:    17/07/10 12:13:53 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

We have analysed 9.8 ks of XRT data for the Swift/BAT-detected burst
GRB 170710A (Evans et al. GCN Circ. 21308), from 114 s to 30.4 ks after
the  Swift/BAT trigger. The data comprise 102 s in Windowed Timing (WT)
mode (the first 8 s were taken while Swift was slewing) with the
remainder in Photon Counting (PC) mode. The enhanced XRT position for
this burst was given by Osborne et al. (GCN Circ. 21309).

The light curve can be modelled with an initial power-law decay with an
index of alpha=4.43 (+0.26, -0.23), followed by a break at T+446 s to
an alpha of 0.49 (+0.07, -0.08).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.81 (+/-0.10). The
best-fitting absorption column is  3.6 (+/-0.3) x 10^21 cm^-2, in
excess of the Galactic value of 1.8 x 10^21 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.96 (+0.28, -0.26)
and a best-fitting absorption column of 2.5 (+1.2, -0.7) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 3.7 x 10^-11 (5.1 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      2.5 (+1.2, -0.7) x 10^21 cm^-2
Galactic foreground: 1.8 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.96 (+0.28, -0.26)

If the light curve continues to decay with a power-law decay index of
0.49, the count rate at T+24 hours will be 0.011 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.1 x
10^-13 (5.7 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/00761119.

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


GRB_name: GRB170710A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21313
SUBJECT: GRB 170710A: Swift-BAT refined analysis
DATE:    17/07/10 17:03:52 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), 
J. R. Cummings (CPI), P. A. Evans (U Leicester),
H. A. Krimm (NSF/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-240 to T+607 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 170710A (trigger #761119)
(Evans et al., GCN Circ. 21308).  The BAT ground-calculated position is
RA, Dec = 231.851, -38.523 deg which is 
  RA(J2000)  =  15h 27m 24.2s 
  Dec(J2000) = -38d 31' 22.2" 
with an uncertainty of 3.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 22%.

The mask-weighted light curve shows a single-peaked structure that starts
and peaks at ~T0, and ends at ~T+37 s. T90 (15-350 keV) is 32.6 +- 10.5 sec 
(estimated error including systematics).

The time-averaged spectrum from T+0.16 to T+36.91 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.91 +- 0.37.  The fluence in the 15-150 keV band is 7.4 +- 1.7 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.48 sec in the 15-150 keV band
is 1.0 +- 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/761119/BA/


GRB_name: GRB170708A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21314
SUBJECT: IPN Triangulation of GRB 170708A (short)
DATE:    17/07/10 18:39:30 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, and

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

A short-duration GRB 170708A (Xiong et al., GCN Circ. 21307)
has been detected by Konus-Wind, Fermi (GBM; trigger 521168776),
and INTEGRAL (SPI-ACS), so far, at about 3971 s UT (01:06:11).

We have triangulated it to a preliminary, 3 sigma error box whose 
coordinates are:
---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
   335.835 (22h 23m 20s) +19.798 (+19d 47' 51")
  Corners:
   333.909 (22h 15m 38s) +21.274 (+21d 16' 26")
   336.055 (22h 24m 13s) +19.813 (+19d 48' 47")
   337.608 (22h 30m 26s) +18.268 (+18d 16' 06")
   335.615 (22h 22m 28s) +19.781 (+19d 46' 52")
  ---------------------------------------------
The error box area is 2441 sq. arcmin, and its maximum
dimension is 4.60 deg (the minimum one is 16.6 arcmin).
The Sun distance was 116 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB170708_T03974/IPN/

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


GRB_name: GRB170710A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21315
SUBJECT: GRB170710A: Swift/UVOT detection
DATE:    17/07/10 19:37:22 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld@ucl.ac.uk>

A. A. Breeveld (UCL-MSSL), 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 170710A 
132 s after the BAT trigger (Evans et al., GCN Circ. 21308).
An optical afterglow consistent with the enhanced XRT position (Osborne 
et al., GCN Circ. 21310) and Gemini position (Cuchhiara, GCN Circ. 
21311) is detected in the initial UVOT white finding chart.

Preliminary detection and 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           132          281          147         20.95 +/- 0.3
white             5808         6007          197         >21.0
v                 2122         2141           19         >17.9
b                  546          565           19         >18.9
u                  290          539          246         >20.2
w1                2171         2166           20         >17.1
w2                2098         2117           20         >17.6

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening of E(B-V) = 0.172 in the direction of 
the burst (Schlegel et al. 1998).


GRB_name: GRB170710B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21316
SUBJECT: GRB 170710B: Swift detection of a burst
DATE:    17/07/11 00:48:37 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

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

At 08:10:06.251 UT on 2017-07-10, the Swift Burst Alert Telescope (BAT)
detected a GRB during a pre-planned slew to a scheduled target.
Ground analysis using data from T-25 to T+79 s finds the source at a
location of
RA, Dec = 43.122, 42.679 deg which is
  RA(J2000)  =  02h 52m 29.3s
  Dec(J2000) = +42d 40' 43.6"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).

The mask-weighted light curve shows a single FRED-like pulse that starts
and peaks at ~T0, and ends at ~T+60 s. T90 (15-350 keV) is 54.4 +- 1.6 sec
(estimated error including systematics).

The time-averaged spectrum from T+0.0 to T+59.2 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.38 +- 0.08.  The fluence in the 15-150 keV band is 2.4 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+5.10 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.

This GRB also triggered Fermi/GBM (GBM trigger# 521367012).

A Swift Target of Opportunity observation has been requested.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/00086619001/BA/


GRB_name: GRB170710B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21317
SUBJECT: GRB 170710B: Swift ToO observations
DATE:    17/07/11 07:01:17 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift has initiated a ToO observation of the Fermi/GBM GRB 170710B. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020777

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 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: GRB170710B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21318
SUBJECT: GRB 170710B: Swift-XRT and UVOT observations
DATE:    17/07/11 14:52:33 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), B. Sbarufatti (INAF-OAB/PSU), D.N.
Burrows (PSU), A. Cholden-Brown (PSU), B. Mingo (U. Leicester), A.P.
Beardmore (U. Leicester), A.A. Breeveld (MSSL/UCL), S.B. Cenko (GSFC)
and P.A. Evans (U. Leicester) report on behalf of the Swift team:

Swift has performed follow-up observations of the BAT and
Fermi/GBM-detected burst GRB 170710B (Palmer & Lien, GCN Circ. 21316),
collecting 4.0 ks of Photon Counting (PC) mode data between T0+85.2 ks
and T0+92.7 ks. 

One uncatalogued X-ray source has been detected consistent with being
within 296 arcsec of the BAT position; it is below the RASS limit and
shows no definitive signs of fading. It is 4.8" from SDSS
J025227.08+423819.4, which is a possible quasar, therefore more data
are needed to confirm whether the XRT source is the GRB afterglow.
Further observations are planned. Details of this source are given
below:

Source 1:
  RA (J2000):  43.1110  =  02:52:26.65
  Dec (J2000): +42.6391  =  +42:38:20.7
  Error: 3.3 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: (6.4 [+1.6, -1.4])e-3 ct s^-1   
  Distance: 146 arcsec from BAT position.
  Flux: (2.51 [+0.61, -0.56])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)


The UVOT started observing this source 85.2 ks after the burst. The
catalogued source just on the edge of the XRT region is detected, but
no new source is found to an upper limit in the UVW2 filter of 21.3 mag
in 3924s of exposure.

Two uncatalogued X-ray 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/00020777.

This circular is an official product of the Swift2 team.


GRB_name: GRB170710B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21319
SUBJECT: GRB 170710B: Fermi GBM observation
DATE:    17/07/11 15:33:25 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007@uah.edu>

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

"At 08:10:08.00 UT on 10 July 2017, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 170710B (trigger 521367012 / 170710340)
which was also detected by the Swift/BAT
(D. Palmer et al. 2017, GCN  21316)
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 49
degrees.

The GBM light curve consists of one main peak
with a duration (T90) of about 42 s (50-300 keV).
The time-averaged spectrum from T0-4 s to T0+28 s is
adequately fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.2 +/- 0.1 and
the cutoff energy, parameterized as Epeak, is 293 +/- 61 keV.
A Band function fits the spectrum equally well
with Epeak= 149 +/- 49 keV, alpha = -0.9 +/- 0.2 and beta = -1.9 +/- 0.2.

The event fluence (10-1000 keV) in this time interval is
(6.0 +/- 0.4)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.5 s in the 10-1000 keV band
is 2.7 +/- 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: GRB170705A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21320
SUBJECT: GRB 170705A: TShAO optical observations
DATE:    17/07/11 17:39:03 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

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

We observed the field of the Swift GRB 170705A (Starling et al. GCN 
21289) which is also detected by GBM/Fermi and Konus-Wind  (Bissaldi  et 
al., GCN 21297; Svinkin et al., GCN 21299)  with Zeiss-1000 1-m 
telescope of Tien Shan Astronomical Observatory on July 6-8.  We took 
several images in R-filter.  The optical afterglow  of GRB 170705A 
(Starling et al. GCN 21289, Lipunov et al. GCN 21291, Butler et al. GCN 
21293, Emery et al. GCN 21294; Ugarte Postigo et al. GCN 21298)  is 
visible in a combined image on July 6, and upper limit only for July 
7-8. Preliminary  photometry of the afterglow is following.

Date       UT start   t-T0    Filter Exp.  OT     Err. UL
                      (mid, days)     (s)             (3 sigma)

2017-07-06 16:28:29  1.61411  R    38*180  20.67  0.24 21.1
2017-07-07 17:30:55  2.63106  R    13*180  n/d    n/d  20.6
2017-07-07 17:30:55  3.10501  R    34*180  n/d    n/d  21.1

Photometry is based on nearby SDSS DR9 stars listed in GCN 21300.


GRB_name: GRB170711A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21321
SUBJECT: GRB 170711A: Swift detection of a burst
DATE:    17/07/11 22:32:34 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

V. D'Elia (ASDC), D. N. Burrows (PSU), A. Cholden-Brown (PSU),
A. D'Ai (INAF-IASFPA), H. A. Krimm (NSF/USRA), D. M. Palmer (LANL) and
B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team:

At 22:20:25 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 170711A (trigger=761622).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 45.786, +47.850 which is 
   RA(J2000) = 03h 03m 09s
   Dec(J2000) = +47d 51' 01"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  Due to a data gap, the BAT light curve is
currently available only until 8 seconds after the trigger. 
The available BAT lightcurve showed a single-peaked
structure with a duration of about 10 sec.  The peak count rate
was ~7000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 22:21:28.7 UT, 63.4 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source located at RA, Dec 45.79854, 47.84896 which
is equivalent to:
   RA(J2000)  = 03h 03m 11.65s
   Dec(J2000) = +47d 50' 56.3"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 30 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 3.23
x 10^21 cm^-2 (Willingale et al. 2013). 

UVOT took a finding chart exposure of 250 seconds with the U filter starting
123 seconds after the BAT trigger. No credible afterglow candidate has been
found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the
XRT error circle. The typical 3-sigma upper limit has been about 19.2 mag. The
8'x8' region for the list of sources generated on-board covers 100% of the XRT
error circle. The list of sources is typically complete to about 18.0 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.31. 

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: GRB170711A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21322
SUBJECT: GRB 170711A: Prompt enhanced Swift-XRT position
DATE:    17/07/11 22:59:31 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 170711A, we find an
enhanced XRT position of the afterglow: RA, Dec: 45.8014, 47.8489 which
is equivalent to:
   RA (J2000)  = 03 03 12.33
   Dec (J2000) = +47 50 55.9
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/761622.

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: GRB170711A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21323
SUBJECT: GRB 170711A: Enhanced Swift-XRT position
DATE:    17/07/12 00:32:59 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 1474 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 170711A, 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 = 45.80093, +47.84897 which is equivalent
to:

RA (J2000): 03h 03m 12.22s
Dec (J2000): +47d 50' 56.3"

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

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

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


GRB_name: GRB170711A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21324
SUBJECT: GRB 170711A: Fermi GBM observation
DATE:    17/07/12 03:21:47 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007@uah.edu>

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

"At 22:20:25.30 UT on 11 July 2017, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 170711A (trigger 521504430 / 170711931)
which was also detected by the Swift/BAT
(V. D'Elia et al. 2017, GCN 21321)
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 32
degrees.

The GBM light curve shows one spike
with a duration (T90) of about 12 s (50-300 keV).
The time-averaged spectrum from T0-2.6 s to T0+10.8 s is
well fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.5 +/- 0.1 and
the cutoff energy, parameterized as Epeak, is 155 +/- 34 keV.

The event fluence (10-1000 keV) in this time interval is
(2.6 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.3 s in the 10-1000 keV band
is 7.2 +/- 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: GRB170711A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21325
SUBJECT: GRB 170711A: Swift-XRT refined Analysis
DATE:    17/07/12 03:58:36 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), A.
Cholden-Brown (PSU), S. J. LaPorte (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 6.1 ks of XRT data for GRB 170711A (D'Elia et al. GCN
Circ. 21321), from 51 s to 13.0 ks after the  BAT trigger. The data
comprise 6 s in Windowed Timing (WT) mode (taken while Swift was
slewing), with the remainder in Photon Counting (PC) mode. The enhanced
XRT position for this burst was given by Beardmore et al. (GCN Circ.
21322).

The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=3.2 (+0.8, -0.7). At T+160 s  the decay
flattens to an alpha of -0.14 (+0.25, -0.65) before breaking again at
T+1004 s to a final decay with index alpha=0.59 (+0.36, -0.11).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.08 (+0.22, -0.21). The
best-fitting absorption column is  6.7 (+1.5, -1.3) x 10^21 cm^-2, in
excess of the Galactic value of 3.2 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 4.2 x 10^-11 (7.6 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      6.7 (+1.5, -1.3) x 10^21 cm^-2
Galactic foreground: 3.2 x 10^21 cm^-2
Excess significance: 4.2 sigma
Photon index:      2.08 (+0.22, -0.21)

If the light curve continues to decay with a power-law decay index of
0.59, 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 7.7 x
10^-13 (1.4 x 10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00761622.

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


GRB_name: GRB170710C
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21326
SUBJECT: GRB 170710C: a long GRB detected by INTEGRAL
DATE:    17/07/12 10:29:14 GMT
FROM:    Sandro Mereghetti at IASF-Milano/INAF  <sandro@iasf-milano.inaf.it>

S.Mereghetti (IASF-Milano), D.Gotz (CEA, Saclay), C.Ferrigno, E.Bozzo,and 
J.Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report:

a gamma ray burst lasting about 30 s has been detected by IBAS in the 
IBIS/ISGRI data at 05:05:15 UT of July 10, 2017. Its significance was 
below the threshold for automatic alert delivery

The refined coordinates (J2000) are:

R.A.= 352.2526 deg
DEC.= +51.2935 deg

with an uncertainty of  2.5   arcmin (90% c.l.).

The burst had a peak flux of 0.3 counts/cm2/s (20-200 keV, 1-s integration
time) and a fluence in the same energy range of about 4x10e-7 erg/cmq.

A plot of the light curve will  be posted at
http://ibas.iasf-milano.inaf.it/IBAS_Results.html


GRB_name: GRB170705A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21327
SUBJECT: GRB 170705A: AstroSat CZTI detection
DATE:    17/07/12 13:18:15 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

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

Analysis of Astrosat CZTI data showed the detection of a long-duration GRB 170705A, which was also detected by Swift/BAT (Starling et al., GCN 21289), Fermi/GBM (Bissaldi et al., GCN 21297), Konus-Wind (Svinkin et al., GCN 21299) and Insight-HXMT (Lu et al., GCN 21301).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with the strongest peak at 02:46:00 UT, ~13 s after the Swift Trigger. The measured peak count rate is 635.9 cts/s above the background in combined data of four quadrants, with a total of 3123 cts. The local mean background count rate was 374.1 cts/s. Using cumulative rates, we measure a T90 of 14.9 s.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

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: GRB170711A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21328
SUBJECT: GRB 170711A: RATIR Optical and NIR Observations
DATE:    17/07/12 15:32:17 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), JesÃºs
GonzÃ¡lez (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM), Harvey Moseley (GSFC), John
Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:

We observed the field of GRB 170711A (D'Elia, et al., GCN 21321) 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 2017/07 12.46 to 2017/07 12.48 UTC (12.68 to
13.13 hours after the BAT trigger), obtaining a total of 0.33 hours
exposure in the r and i bands and 0.14 hours exposure in the Z, Y, J, and H
bands.

For a source within the Swift-XRT error circle (Beardmore, et al., GCN
21323), in comparison with the USNO-B1 and 2MASS catalogs, we obtain the
following upper limits (3-sigma):

 r > 22.94
 i > 22.86
 Z > 21.61
 Y > 21.45
 J > 21.08
 H > 20.83

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: GRB170711A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21329
SUBJECT: GRB 170711A: Swift/UVOT Upper Limits
DATE:    17/07/12 16:20:43 GMT
FROM:    Frank Marshall at GSFC  <femarsha@khamseen.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC) and V. D'Elia (ASDC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 170711A
124 s after the BAT trigger (D'Elia et al., GCN Circ. 21321).
No optical afterglow consistent with the enhanced XRT position
(Beardmore et al. GCN Circ. 21323) 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 initial exposures are:

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

u_FC               124          374          246         >19.8
v                  430         1553          136         >18.9
b                  379         1503          156         >19.4
w1                 480         1454           97         >19.6
m2                 604         1429           58         >18.6
w2                 704         1380           78         >19.0

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.31 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB170708A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21330
SUBJECT: Konus-Wind observation of GRB 170708A
DATE:    17/07/12 16:23:08 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 GRB 170708A
(IPN triangulation: Svinkin et al., GCN Circ. 21314;
Insight-HXMT detection: Xiong et al., GCN Circ. 21307)
triggered Konus-Wind at T0=3974.665 s UT (01:06:14.665).

The burst light curve shows a single pulse with
a total duration of ~0.2 s.
The emission is seen up to ~500 keV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB170708_T03974/

As observed by Konus-Wind, the burst
had a fluence of 8.04(-1.2,+1.4)x10^-7 erg/cm2,
and a 16-ms peak flux, measured from T0-0.014 s,
of 1.48(-0.37,+0.40)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated 3-channel spectrum of the burst,
measured from T0-0.014 s to T0+0.224 s,
can be modelled by an exponentially cut off power law:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.94(-0.30,+0.42) and Ep = 269(-75,+147) keV.

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


GRB_name: GRB170711A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21331
SUBJECT: GRB 170711A: Swift-BAT refined analysis
DATE:    17/07/12 19:23:15 GMT
FROM:    Hans Krimm at NSF/NASA-GSFC  <hkrimm@nsf.gov>

C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), J. R. Cummings (CPI),
V. D'Elia (ASDC), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):

Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 170711A (trigger #761622)
(D'Elia, et al., GCN Circ. 21321).  The BAT ground-calculated position is
RA, Dec = 45.782, 47.845 deg which is
  RA(J2000)  =  03h 03m 07.7s
  Dec(J2000) = +47d 50' 41.2"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.

The mask-weighted light curve shows a single FRED-shaped peak, starting at
T-2 sec, peaking at T+0 sec and decaying to background by T+6 sec.  This is
preceded by some weak, soft emission beginning at about T-25 sec.
T90 (15-350 keV) is 31.3 +- 7.6 sec (estimated error including systematics).

The time-averaged spectrum from T-31.66 to T+15.37 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.75 +- 0.10.  The fluence in the 15-150 keV band is 1.4 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+0.02 sec in the 15-150 keV band
is 4.8 +- 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/761622/BA/


GRB_name: GRB170712A
Detection_method: Insight-HXMT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21332
SUBJECT: GRB 170712A: Insight-HXMT detection
DATE:    17/07/13 08:03:16 GMT
FROM:    Shaolin Xiong at IHEP  <xiongsl@ihep.ac.cn>

L. M. Song, X. B. Li, S. L.Xiong, J. Y. Liao, X. Ma, C. Z. Liu, X. F. Li,
Z. W. Li, Z. Chang, X. F. Lu, J. L. Zhao, A. M. Zhang, Y. F. Zhang,
C. L. Zou (IHEP), Y. J. Jin, Z. Zhang (THU), M. Gao (IHEP),
T. P. Li (IHEP/THU), M. S. Li, F. J. Lu, W. H. Tao, H. Y. Wang, X. Y. Wen,
M. Wu, Y. P. Xu, C. M. Zhang, F. Zhang, J. Zhang, T. Zhang,
S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team:

During the commissioning phase, at 2017-07-12T03:20:30.00 (T0),
Insight-HXMT detected GRB 170712A (trigger ID: HEB170712139)
in a routine search of the data, which was also observed by
Konus-Wind (trig time: 2017-07-12T03:20:26.59).

The Insight-HXMT light curve consists of multiple pulses
with a duration (T90) of 8.6 s measured from T0-5.82 s.
The 1-second peak rate, measured from T0+0.5 s, is 1948.9 cnts/sec.
The total counts from this burst is 4455 counts.

All measurements above are made with the CsI detectors operating in the
GRB mode, in which the energy range is increased to about 200 - 3000 keV
(record energy) , compared to the normal mode of 80 - 800 keV.
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the telescope.

URL_LC: http://www.hxmt.org/images/GRB/HEB170712139_lc.jpg

The analysis results presented above are preliminary;
final results will be published elsewhere.

Insight-HXMT is the first Chinese space X-ray telescope, which was funded
jointly by the China National Space Administration (CNSA) and the Chinese
Academy of Sciences (CAS). More information about it could be found at:
http://www.hxmt.org/index.php/enhome .


GRB_name: GRB170711A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21333
SUBJECT: GRB 170711A: ISON/Terskol and AbAO optical observations
DATE:    17/07/13 18:13:15 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

A. Volnova (IKI),   A. Pozanenko (IKI),  A. Mokhnatkin (KIAM),  R. 
Inasaridze (AbAO), E. Mazaeva (IKI), V. Agletdinov (KIAM),   V. Ayvazian 
(AbAO),  O. Kvaratskhelia (AbAO), G. Inasaridze (AbAO),    I. Molotov (KIAM) 
report on behalf of  larger GRB follow-up collaboration:

We observed the field of the Swift GRB 170711A (D'Elia  et al. GCN 21321) 
with K-800 (0.8m) telescope  of  ISON/Terskol observatory starting on July, 
12 (UT) 00:00:39 and  AS-32 telescope of AbAO starting  on July, 11 (UT) 
23:58:46, i.e. about 1.6 hours after GRB trigger.  We obtained
several unfiltered images. We do not detect any source in stacked images 
within the enhanced XRT position (Beardmore  et al. GCN 21323).
Preliminary  photometry of the field is following

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

2017-07-11   23:58:46 0.07894 CR      11*60 n/d n/d  17.0     AS-32
2017-07-12   00:00:39 0.07658 CR      45*25 n/d n/d  19.1     K-800

Photometry is based on nearby stars of USNO-B1.0
USNO-B1.0_id   R2
1378-0084355   14.59

1378-0084262   15.13

1378-0084218   14.70

We detect the object in  coordinates (J2000)  03 03 11.46  +47 50 56.1  (+/- 
0.5 arcsec) which is 7.7 arcsec apart from a center of the enhanced XRT 
position. The object is clearly detected in the stacked image of K-800  and 
marginally seen at  the same position with AS-32 stacked image. The 
brightness of the object is 18.56 +/- 0.25 based on the reference stars 
listed above. The object is absent in the  USNO-B1.0. At present, it is not 
clear whether this object has any relation to the GRB 170711A. 


GRB_name: GRB170702A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21334
SUBJECT: GRB 170702A CALET Gamma-Ray Burst Monitor detection
DATE:    17/07/14 00:36:22 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

S. Ozawa (Waseda U), A. Yoshida, T. Sakamoto, Y. Kawakubo, M. Moriyama,
Y. Yamada, A. Tezuka, S. Matsukawa (AGU), K. Yamaoka (Nagoya U),
S. Nakahira (RIKEN), 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), A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long-duration GRB 170702A (INTEGRAL SPI-ACS detection
time on 23:41:33 UT; Swift-BAT detection at the outside of
the field of view) triggered the CALET Gamma-ray Burst Monitor (CGBM)
at 23:41:35.21 on 2 July 2017.  The burst signal was seen by the 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 four peaks.  The emission
starts at T-1 sec, peaks at T+0.5 sec (the first peak), T+2 sec
(the second peak), T+4 sec (the third peak), T+8.3 sec (the fourth
peak) and ends at T+10 sec.  The T90 duration measured by
the SGM data is 7.5 +- 0.4 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1183073582/

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


GRB_name: GRB170703A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21335
SUBJECT: GRB 170703A CALET Gamma-Ray Burst Monitor detection
DATE:    17/07/14 00:50:32 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, A. Tezuka, S. Matsukawa (AGU), K. Yamaoka (Nagoya U),
S. Nakahira (RIKEN), 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), A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long-duration GRB 170703A (Konus-Wind trigger time on
08:44:03.46 UT) triggered the CALET Gamma-ray Burst Monitor (CGBM)
at 08:44:05.85 on 3 July 2017.  The burst signal was seen by the 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 two peaks.  The emission starts at T-2 sec,
peaks at T+1 sec (the first peak), T+ 7 sec (the second peak), and ends at T+20 sec.
The T90 duration measured by the SGM data is 26 +- 3 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1183106132/

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


GRB_name: GRB170708B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21336
SUBJECT: GRB 170708B CALET Gamma-Ray Burst Monitor detection
DATE:    17/07/14 01:02:13 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, A. Tezuka, S. Matsukawa (AGU), K. Yamaoka (Nagoya U),
S. Nakahira (RIKEN), 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), A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long-duration GRB 170708B (Konus-Wind trigger time on
20:37:00.639 UT) triggered the CALET Gamma-ray Burst Monitor (CGBM)
at 20:36:54.18 on 8 July 2017.  The burst signal was only seen by the SGM
instrument.

The light curve of the SGM shows a single peak.  The emission starts at T+2 sec,
peaks at T+4 sec and ends at T+9 sec.  The T90 duration measured by the SGM
data is 5.6 +- 0.7 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1183580890/

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


GRB_name: GRB170710D
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21337
SUBJECT: GRB 170710D CALET Gamma-Ray Burst Monitor detection
DATE:    17/07/14 01:05:56 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, A. Tezuka, S. Matsukawa (AGU), K. Yamaoka (Nagoya U),
S. Nakahira (RIKEN), 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), A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long-duration GRB 170710D (Konus-Wind trigger time on
19:12:50.635 UT) triggered the CALET Gamma-ray Burst Monitor (CGBM)
at 19:12:50.84 on 10 July 2017.  The burst signal was seen by the all CGBM
instrument.

The light curve of the SGM shows a bright single peak.  The emission starts at
T+2 sec, peaks at T+5 sec and ends at T+10 sec.  The T90 duration measured
by the SGM data is 4.9 +- 0.3 sec (40-1000 keV).

The light curve is available at

http://cgbm.calet.jp/cgbm_trigger/flight/1183748644/

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

[GCN OPS NOTE(17jul17):  Per author's request (Circ 21338), 170710C was changed
to 170710D.]


GRB_name: GRB170710D
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21338
SUBJECT: Correction to GCN Circular 21337: GRB 170710D CALET Gamma-Ray Burst Monitor detection
DATE:    17/07/14 07:44:25 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

T. Sakamoto (AGU) and the CALET collaboration

We named the GRB wrongly in our previous GCN circular (Tamura et al.
GCN Circ. 21337).  The correct GRB name is GRB 170710D not GRB 170710C
(since GRB 170710C was already named for the GRB detected by INTEGRAL
on 05:05:15 UT; Mereghetti et al. GCN Circ. 21326).  Apologies for any
confusion caused.

We would like to thank Sandro Mereghetti for pointing out this error.


GRB_name: GRB170712A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21339
SUBJECT: GRB 170712A: AstroSat CZTI detection
DATE:    17/07/14 09:00:49 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

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

Analysis of Astrosat CZTI data showed the detection of a long-duration GRB 170712A, which was also detected by Insight-HXMT (Song et al., GCN 21332) and Konus-Wind (trig time: 2017-07-12 03:20:26.59).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with the strongest peak at 03:20:30 UT, ~1 s before the Insight-HXMT Trigger. The measured peak count rate is 198.6 cts/s above the background in combined data of four quadrants, with a total of 718 cts. The local mean background count rate was 349.8 cts/s. Using cumulative rates, we measure a T90 of 10.8 s.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

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: GRB170714A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21340
SUBJECT: GRB 170714A: Swift detection of a burst
DATE:    17/07/14 12:52:55 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

A. D'Ai (INAF-IASFPA), D. N. Burrows (PSU), A. Cholden-Brown (PSU),
V. D'Elia (ASDC), J. A. Kennea (PSU), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester), D. M. Palmer (LANL) and
B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team:

At 12:25:32 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 170714A (trigger=762535).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 34.321, +1.987 which is 
   RA(J2000) = 02h 17m 17s
   Dec(J2000) = +01d 59' 14"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  As is usual with an image trigger, the available
BAT light curve shows no significant structure. 

The XRT began observing the field at 12:32:05.3 UT, 392.7 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 34.3498, 1.9901 which is equivalent to:
   RA(J2000)  = +02h 17m 23.95s
   Dec(J2000) = +01d 59' 24.4"
with an uncertainty of 5.0 arcseconds (radius, 90% containment). This
location is 104 arcseconds from the BAT onboard position, within the
BAT error circle. No event data are yet available to determine the
column density using X-ray spectroscopy. 

UVOT took a finding chart exposure of 150 seconds with the U filter starting
869 seconds after the BAT trigger. No credible afterglow candidate has been
found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the
XRT error circle. The typical 3-sigma upper limit has been about 19.2 mag. The
8'x8' region for the list of sources generated on-board covers 100% of the XRT
error circle. The list of sources is typically complete to about 18.0 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.03. 

Burst Advocate for this burst is A. D'Ai (antonino.dai AT ifc.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: GRB170714A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21341
SUBJECT: GRB 170714A: Enhanced Swift-XRT position
DATE:    17/07/14 15:23:59 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 641 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 170714A, 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 = 34.34983, +1.99204 which is equivalent
to:

RA (J2000): 02h 17m 23.96s
Dec (J2000): +01d 59' 31.3"

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

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

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


GRB_name: GRB170714A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21343
SUBJECT: GRB 170714A: Swift-XRT refined Analysis
DATE:    17/07/15 01:16:20 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. Cholden-Brown (PSU), S. J.
LaPorte (PSU), J.A. Kennea (PSU), A.P. Beardmore (U. Leicester), P.A.
Evans (U. Leicester), S.L. Gibson (U. Leicester) and A. D'Ai report on
behalf of the Swift-XRT team:

We have analysed 8.8 ks of XRT data for GRB 170714A (D'Ai et al. GCN
Circ. 21340), from 383 s to 22.6 ks after the  BAT trigger. The data
comprise 1.3 ks 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. 21341). The late-time light curve (from T0+5.0 ks) is
consistent with a constant source of mean count rate 1.4e+01 ct/sec. A
power-law fit gives an index of 1.7 (+1.8, -2.8).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.588 (+/-0.018). The
best-fitting absorption column is  9.3 (+/-0.6) x 10^20 cm^-2, in
excess of the Galactic value of 3.6 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.73 (+/-0.05) and a
best-fitting absorption column of 9.0 (+/-1.5) x 10^20 cm^-2. The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 3.9 x 10^-11 (4.4 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      9.0 (+/-1.5) x 10^20 cm^-2
Galactic foreground: 3.6 x 10^20 cm^-2
Excess significance: 6.1 sigma
Photon index:      1.73 (+/-0.05)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00762535.

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


GRB_name: GRB170714B
Detection_method: Insight-HXMT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21344
SUBJECT: GRB 170714B: Insight-HXMT detection
DATE:    17/07/15 03:17:38 GMT
FROM:    Shaolin Xiong at IHEP  <xiongsl@ihep.ac.cn>

S. N. Zhang, C. K. Li, J. Y. Liao, S. L. Xiong, C. Z. Liu, X. F. Li,
Z. W. Li, Z. Chang, X. F. Lu, J. L. Zhao, A. M. Zhang, Y. F. Zhang,
C. L. Zou (IHEP), Y. J. Jin, Z. Zhang (THU), T. P. Li (IHEP/THU),
F. J. Lu, L. M. Song, H. Y. Wang, M. Wu, Y. P. Xu (IHEP),
report on behalf of the Insight-HXMT team:

During the commissioning phase, at 2017-07-14T01:10:51.10 (T0),
Insight-HXMT detected GRB 170714B (trigger ID: HEB170714049)
in a routine search of the data, which was also observed by the
Fermi/GBM (trig # 521687456).

The Insight-HXMT light curve consists of a short pulse
with a duration (T90) of 0.052 s measured from T0-0.002 s.
The 30-ms peak rate, measured from T0+0.01 s, is 3050.7 cnts/sec.
The total counts from this burst is 169 counts.
The detection significance of Insight-HXMT is ~8 sigma.

URL_LC: http://www.hxmt.org/images/GRB/HEB170714049_lc.jpg

All measurements above are made with the CsI detectors operating in the
GRB mode, in which the energy range is increased to about 200 - 3000 keV
(record energy) , compared to the normal mode of 80 - 800 keV.
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the telescope.

The analysis results presented above are preliminary;
final results will be published elsewhere.

Insight-HXMT is the first Chinese space X-ray telescope, which was funded
jointly by the China National Space Administration (CNSA) and the Chinese
Academy of Sciences (CAS). More information about it could be found at:
http://www.hxmt.org/index.php/enhome .


GRB_name: GRB170714A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21345
SUBJECT: GRB 170714A: Bastille Day Burst: ULGRB or RTDE?
DATE:    17/07/15 03:48:00 GMT
FROM:    Alexander Kann at TLS Tautenburg  <kann@tls-tautenburg.de>

D. A. Kann, A. de Ugarte Postigo, L. Izzo, and C. C. Thoene
(HETH/IAA-CSIC) report:

GRB 170714A (D'Ai et al. GCN #21340) exhibits very variable behavior in
its X-ray light curve beyond what is reported by D'Avanzo et al. (GCN
#21343). We especially point out a very rapid decay at ~ 18ks, from ~5
ct/s to 0.01 ct/s in about 1.3 ks. Even after this steep decay, which is a
typical sign of central-engine turn-off, the XRT light curve shows flaring
activity of a factor of ~5. All this activity is usually the sign of an
active central engine.

This highly variable behavior is reminiscent of two types of sources:
Ultra-long GRBs like GRBs 101225A, 111209A and 130925A (e.g., Thoene et
al., Nature, 480, 72; Gendre et al., ApJ, 766, 30; Levan et al., ApJ, 781,
13; Greiner et al., A&A, 568, A75; Kann et al., A&A, submitted,
arXiv:1706.00601) or relativistic tidal disruption events such as Sw J1644
(e.g., Levan et al., Science, 333, 199).

So far no optical source has been reported, and the X-ray afterglow shows
signs of additional absorption (D'Avanzo et al., GCN #21343), which may be
indicative of a reddened source in the center of its host and therefore a
RTDE. On the other hand, the source is significantly brighter than Sw
J1644, and no obvious host galaxy is seen in SDSS or PanSTARRS
pre-imaging. The hosts of GRBs 101225A and 111209A were also very faint,
and GRB 130925A showed very strong absorption.

If this event is an ULGRB, the flaring activity persists for nearly 40ks
until now, making it significantly longer than even GRB 111209A.

Despite the inclement visibility, observations of this source are strongly
encouraged.


GRB_name: GRB170714A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21346
SUBJECT: GRB 170714A: z-band afterglow candidate for OSIRIS/GTC
DATE:    17/07/15 06:37:17 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), D. A. Kann 
L. Izzo, C. C. Thoene (HETH/IAA-CSIC), N. Castro-Rodriguez 
(GTC, IAC, ULL), A. Marante, J. A. Melian (GTC) report:

We observed the field of GRB 170714A (D'Ai et al. GCN 21340), an 
ULGRB or RTDE candidate (Kann et al., GCN 21345) with OSIRIS at 
the 10.4m GTC telescope in La Palma (Spain). Observations consisted 
in several short exposures in i and z filters. The observations were not 
easy, as the field was located 30 deg away from the 68% illuminated 
Moon, implying a very high background.

In the combined z-band frame, with mean epoch at 05:10:24 UT (16.75 hr 
after the burst) we detect a single object within the refined XRT error box 
(Evans et al. GCN 21341) which is not present in PanSTARRS imaging, 
with coordinates (J2000):

R.A.: 02:17:23.99
Dec.: +01:59:29.51

and a magnitude of z(AB)=22.3+/-0.2, which we identify as the possible 
GRB afterglow, although we cannot make any statement about 
variability at this time. In our preliminary analysis we do not detect the 
object in any other band, implying a possible strong reddening.

Further follow up, especially in NIR bands is encouraged.


GRB_name: GRB170714A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21347
SUBJECT: GRB 170714A, Swift-BAT refined analysis
DATE:    17/07/15 15:32:14 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), A. D'Ai (INAF-IASFPA),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):

Using the data set from T-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 170714A (trigger #762535)
(D'Ai et al., GCN Circ. 21340).  The BAT ground-calculated position is
RA, Dec = 34.322, 1.962 deg which is
  RA(J2000)  =  02h 17m 17.3s
  Dec(J2000) = +01d 57' 43.3"
with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 61%.

The mask-weighted light curve shows continuous weak emission that starts
at ~ T-70 s and lasts beyond the end of the event data (T+963 s).

The time-averaged spectrum from T-72.9 to T+464.4 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.76 +- 0.17.  The fluence in the 15-150 keV band is 2.8 +- 0.3 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+262.88 sec in the 15-150 keV band
is 0.4 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/762535/BA/


GRB_name: GRB170702A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21348
SUBJECT: GRB 170702A: AstroSat CZTI detection
DATE:    17/07/15 20:38:55 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

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

Analysis of AstroSat CZTI data showed clear detection of GRB 170702A (CALET Gamma-Ray Burst Monitor detection: Ozawa S. et al, GCN Circ. 21334) in the 40-200 keV energy range. The light curve shows multiple peaks of emission with the strongest peak at 23:41:36.0 UT, around ~2 s after the CALET trigger. The measured peak count rate is 1192.5 counts/s above the background in combined data of four quadrants, with a total 3911 counts. The local mean background count rate was 334.5 counts/s. Using cumulative rates, we measure a T90 of 8.7 s.

It was clearly detected in the CsI anticoincidence detector (Veto) also as bright detection in the 100-500 keV energy range.

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: GRB170714A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21350
SUBJECT: GRB 170714A: TNG NIR observations
DATE:    17/07/17 14:05:22 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>

P. D'Avanzo, A. Melandri (INAF-OAB), V. D'Elia (INAF/OAR & ASI/ASDC), G. Mainella, W. Boschin (INAF-TNG) report on behalf of the CIBO collaboration: 

We observed the field of GRB 170714A (D'Ai et al. GCN 21340) with the 3.6m Telescopio Nazionale Galileo (TNG) equipped with NICS. Observations were carried out in the near-infrared with the J filter under poor weather conditions (clouds and calima). Observations started on Jul 16 at 04:05:03 UT (~1.65 days after the burst) and consisted in a series of images for a total exposure time of 17 minutes.

No source is detected in the refined XRT error circle (Evans et al. GCN 21341). In particular we could not detect the candidate afterglow reported by de Ugarte Postigo et al. (GCN. 21346). 

For the coadded image we estimate a preliminary 3sigma upper limit of J > 19.6 mag (AB, calibrated against the 2MASS catalogue).


GRB_name: GRB170714A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21351
SUBJECT: GRB 170714A: Swift/UVOT Observations
DATE:    17/07/17 19:28:04 GMT
FROM:    Frank Marshall at GSFC  <femarsha@khamseen.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC) and A. D'Ai (INAF-IASFPA)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 170714A
384 s after the BAT trigger (D'Ai et al., GCN Circ. 21340).
There is weak evidence for a fading source consistent with the
position of the z-band afterglow candidate reported by
de Ugarte Postigo et al. (GCN Circ. 21346).
Preliminary detections and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag
v                  384         1695          175         >18.6
b                  496         1644          155         20.0 +/- 0.33
b                 5390        24672         1011         >20.3
u                  471         1619          284         20.1 +/- 0.35
u                 5185        30412         2351         20.4 +/- 0.18
u                81432        92912         1509         >20.7
w1                 446         1594          136         >21.0
m2                6006        29000         2637         >20.9
w2                5596        34449         3032         >22.0

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).

[GCN OPS NOTE(17jul17): Per author's request, please see GCN Circ 21353
for corrections to the above table.]


GRB_name: GRB170714A
Detection_method: VLA Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21352
SUBJECT: GRB170714A: VLA Observations of the Bastille Day Ultra-long Burst 
DATE:    17/07/17 19:51:14 GMT
FROM:    Assaf Horesh at Hebrew U, Jerusalem  <assafh@mail.huji.ac.il>

A. Horesh (HUJI), S. B. Cenko (NASA/GSFC), A. Levan (U. Warwick), and N. Tanvir (U. Leicester) report:

We observed the ultra-long gamma-ray burst (T90 > 1000s; Dâ€™Ai et al. GCN 21340; Evans et al. GCN 21341; Kann et al. GCN 21345; Palmer et al. GCN 21347) with the Jansky Very Large Array (VLA). 
Our observation was undertaken on 2017 July 16 in the C configuration.

We do not detect radio emission at the enhanced XRT position of the source, with a 3 sigma detection limit of 75 micro-Jy at a central frequency of 7.5 GHz. 

Future VLA observations are planned under our program to search for late-time emission. 

We thank the VLA staff for scheduling this target of opportunity.


GRB_name: GRB170714A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21353
SUBJECT: Correction to GCN Circular 21351: GRB 170714A: Swift/UVOT Observations
DATE:    17/07/17 21:37:38 GMT
FROM:    Frank Marshall at GSFC  <femarsha@khamseen.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC) 
reports on behalf of the Swift/UVOT team:

Some of the Swift UVOT exposures of GRB 170714A
previously reported by Marshall and D'Ai (GCN Circular 21351)
contain readout streaks due to nearby bright sources.
These streaks make the determination of magnitudes very difficult,
and this effect was not accounted for in the previous analysis.
The affected exposures have been removed from the corrected
table given below. As a result, the most significant detection
of a source with UVOT has been removed, and there is now
only weak evidence for a UVOT source at the position of
the z-band afterglow candidate reported by
de Ugarte Postigo et al. (GCN Circ. 21346).

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

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag
v                  397         1695          175         >18.6
b                  496         1644          155         20.0 +/- 0.33
b                92917        93309          382         >20.3
u                  471         1619          284         20.1 +/- 0.35
u                81432        92912         1509         >20.7
w1                 446         1594          136         >21.0
m2               76276        98985         2438         >21.3
w2               74458        86274         1771         >21.5

I apologize for any confusion caused by the earlier report.


GRB_name: GRB170710B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21354
SUBJECT: GRB 170710B: Further Swift-XRT observations
DATE:    17/07/18 05:38:42 GMT
FROM:    Kim Page at U.of Leicester  <klp5@leicester.ac.uk>

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

Swift performed a further observation of the field of the BAT and
Fermi/GBM-detected burst GRB 170710B (Palmer & Lien, GCN Circ. 21316;
Hamburg, Meegan & Bissaldi, GCN Circ. 21319) on 2017 July 15. The
XRT-detected "Source 1", as given in Page et al. (GCN Circ. 21318), shows
no sign of fading, with a count rate of (5.6 +1.9/-1.5)x10^-3 count s^-1
compared to (6.4 +/- 1.5)x10^-3 count s^-1 from the first observation on
July 11. This is therefore not the GRB afterglow.

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


GRB_name: GRB170714A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21356
SUBJECT: GRB 170714A: NOEMA non-detection of the Bastille Day Burst
DATE:    17/07/18 14:30:07 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), D.A. Kann 
(HETH/IAA-CSIC), S. Schulze (Weizmann Institute), L. Izzo, 
C.C. Thoene (HETH/IAA-CSIC) and M. Krips (IRAM) report:

We observed the field of GRB 170714A (D'Ai et al. GCN 21340) 
using the NOrthern Extended Millimeter Array (NOEMA, Plateau 
de Bure, France) tuned at 92.5 GHz. Observations were 
performed between 3:10 and 5:15 UT on 17 July 2017 (2.66 days 
after the burst) and consisted of 1.33 hr on target with a bandwidth 
of 3.6 GHz and using 8 antennas.

We do not detect any source consistent with the afterglow position 
(de Ugarte Postigo et al. GCN 21346) down to a 3-sigma limit of 
150 uJy. We do note the presence of an unrelated source 12â€ 
Northwest of the afterglow position with a flux density of ~0.19 mJy, 
which is coincident with an extended source in our GTC images.

This burst has been proposed to be either an ultra-long GRB or a
relativistic tidal-disruption event (Kann et al., GCN 21345). We 
note that this deep non-detection, together with the non-detection 
from the VLA (Horesh et al. GCN 21352) are consistent with a 
scenario of an ULGRB like GRBs 101225A, 111209A and 130925A, 
which have been faint at radio wavelengths (Frail, GCN 11550, 
Zauderer et al., GCN 11770; Hancock et al., GCNs 12664, 12804; 
Horesh et al. 2015, ApJ, 812, 86). Relativistic tidal-disruption events 
such as Sw J1644 and SwJ2058 have been found to be much 
brighter in radio wavelengths (e.g., Zauderer et al. 2011, Nature, 
476, 425, Berger et al. 2012, ApJ, 748, 36, Zauderer et al., 2013, 
ApJ, 767, 152; Cenko et al. 2012, ApJ, 753, 77).


GRB_name: GRB170714A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21359
SUBJECT: GRB 170714A: Bastille Day Burst redshift from OSIRIS/GTC
DATE:    17/07/21 06:36:26 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), D.A. Kann, 
L. Izzo, C.C. Thoene (HETH/IAA-CSIC), G. Lombardi S. Geier 
(GTC, IAC-ULL), A. Garcia, A. Perez (GTC) report:

Following the detection of the afterglow (de Ugarte Postigo et al. GCN 
21346) of the ultra-long GRB 170714A (D'Ai et al. GCN 21340, Kann 
et al. GCN 21345) we obtained further NIR and optical observations on 
19 and 20 of July, with detections in r, i, z, and H-bands. An object is 
still observed at the position earlier reported, indicating an important 
host galaxy contribution.

On 21 July, at 4:53 UT (5.69 days after the burst) we obtained 
spectroscopy of the afterglow/host galaxy with OSIRIS at the 10.4m 
GTC telescope (La Palma, Spain). Observations consisted of 4x900 s
with grism R1000R, covering the range between 5100 and 10000 AA.

The combined spectrum shows a weak trace with several 
superimposed emission lines, which we interpret as due to [OII], [OIII] 
and H-beta, through which we derive a redshift for the host galaxy, 
and hence for GRB 170714A, of 0.793.


GRB_name: GRB170714A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21360
SUBJECT: GRB170714A: ATCA observation
DATE:    17/07/22 22:50:47 GMT
FROM:    Luigi Piro at INAF  <luigi.piro@iaps.inaf.it>

R. Ricci (INAF/IRA-Bologna), M. Wieringa (ATNF,CSIRO), L. Piro(INAF/IAPS),
E. Troja(NASA/GSFC), K. Bannister (ATNF,CSIRO) and B. 
Gendre (Virgin Islands University) report:

We observed the ultra-long gamma-ray burst GRB170714A (D'Ai' et al. GCN 
21340; Evans et al. GCN 21341; Kann et al. GCN 21345; Palmer et al. GCN 
21347) with ATCA  on 2017 July 20 at 17 and 21 GHz.

We detect a source ~7" northward of the position of the GRB optical 
counterpart (de Ugarte Postigo et al. GCN 21346). Given the ATCA 
configuration, this position is consistent at about 2.5 sigma with the GRB 
optical counterpart. However, we cannot exclude contamination from the 
source detected at higher frequency by NOEMA (de Ugarte Postigo et al., 
GCN 21356), thus we conservatively estimate an upper limit of ~ 50uJy at 
19GHz to the radio emission from the GRB.

Future ATCA observations are planned under our program on ultralong GRBs 
(PI:L. Piro).

We thank the ATCA staff for scheduling this target of opportunity.


GRB_name: GRB170724A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21364
SUBJECT: GRB 170724A: Swift detection of a burst
DATE:    17/07/24 00:58:16 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

T. N. Ukwatta (LANL), A. Cholden-Brown (PSU), C. Gronwall (PSU),
J. A. Kennea (PSU), A. Melandri (INAF-OAB) and D. M. Palmer (LANL)
report on behalf of the Swift Team:

At 00:48:44 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 170724A (trigger=764204).  Due to a Sun constraint, 
Swift did not slew to the burst location. 
The BAT on-board calculated location is 
RA, Dec 150.081, -1.048 which is 
   RA(J2000) = 10h 00m 20s
   Dec(J2000) = -01d 02' 50"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  As is typical for an image trigger, the
immediately-available lightcurve show no obvious variation. 

Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 09:13 UT on 2017 October 11. There will thus be no XRT
or UVOT data for this trigger before this time. 

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


GRB_name: GRB170724A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21365
SUBJECT: GRB 170724A, Swift-BAT refined analysis
DATE:    17/07/26 00:30:05 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

T. Sakamoto (AGU), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/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 170724A (trigger #764204)
(Ukwatta et al., GCN Circ. 21364).  The BAT ground-calculated position is
RA, Dec = 150.057, -1.025 deg which is
  RA(J2000)  =  10h 00m 13.7s
  Dec(J2000) = -01d 01' 31.0"
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 58%.

The mask-weighted light curve shows a weak complex structure that
starts at ~T-50 s and ends at ~T+80 s. T90 (15-350 keV) is 98.0 +- 26.1 sec
(estimated error including systematics).

The time-averaged spectrum from T-45.6 to T+63.6 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.46 +- 0.23.  The fluence in the 15-150 keV band is 1.1 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+35.92 sec in the 15-150 keV band
is 0.5 +- 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/764204/BA/


GRB_name: GRB170726A
Detection_method: Insight-HXMT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21366
SUBJECT: GRB 170726A: Insight-HXMT detection
DATE:    17/07/28 06:35:46 GMT
FROM:    Shaolin Xiong at IHEP  <xiongsl@ihep.ac.cn>

X. B. Li, J. Y. Liao, C. K. Li, S. L. Xiong, C. Z. Liu, X. F. Li,
Z. W. Li, Z. Chang, X. F. Lu, J. L. Zhao, A. M. Zhang, Y. F. Zhang,
C. L. Zou (IHEP), Y. J. Jin, Z. Zhang (THU), T. P. Li (IHEP/THU),
F. J. Lu, L. M. Song, H. Y. Wang, M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:

During the commissioning phase, at 2017-07-26T19:02:59.51 (T0),
Insight-HXMT detected GRB 170726A (trigger ID: HEB170726793)
in a routine search of the data, which was also observed by
SPI-ACS (trig time: 2017-07-26T19:02:59.51) and
Fermi/GBM (trig time: 2017-07-26T19:02:59.976).

The Insight-HXMT light curve mainly consists of multi-pulses
with a duration (T90) of 23.7 s measured from T0-5.47 s.
The 1-second peak rate, measured from T0+2 s, is 1364.9 cnts/sec.
The total counts from this burst is 10261.5 counts.

URL_LC: http://www.hxmt.org/images/GRB/HEB170726793_lc.jpg

All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (record energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the telescope.

The time-averaged spectrum from T0-8 s to T0+18 s is
adequately fit by a Power Law model with spectral index = -1.94 +/- 0.05.
The energy fluence is (7.17 +/- 0.38)E-06 erg/cm^2 in 200 - 3000 keV
in this time interval.

The analysis results presented above are preliminary;
final results will be published elsewhere.

Insight-HXMT is the first Chinese space X-ray telescope, which was funded
jointly by the China National Space Administration (CNSA) and the Chinese
Academy of Sciences (CAS). More information about it could be found at:
http://www.hxmt.org/index.php/enhome .


GRB_name: GRB170728A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21367
SUBJECT: GRB 170728A: Swift detection of a burst
DATE:    17/07/28 07:04:25 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

J. K. Cannizzo (NASA/UMBC), A. P. Beardmore (U Leicester),
K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU)
report on behalf of the Swift Team:

At 06:53:28 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 170728A (trigger=765008).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 58.898, +12.153 which is 
   RA(J2000) = 03h 55m 35s
   Dec(J2000) = +12d 09' 11"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single peak
structure with a duration of about 3 sec.  The peak count rate
was ~2400 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 06:54:39.4 UT, 70.6 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source located at RA, Dec 58.88846, 12.18313 which
is equivalent to:
   RA(J2000)  = 03h 55m 33.23s
   Dec(J2000) = +12d 10' 59.3"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 113 arcseconds from the BAT onboard position, within the
BAT error circle. This position may be improved as more data are
received; the latest position is available at
http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 2.27
x 10^21 cm^-2 (Willingale et al. 2013). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 73 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 0.24. 

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: GRB170728A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21368
SUBJECT: GRB 170728A: Enhanced Swift-XRT position
DATE:    17/07/28 10:59:59 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 1579 s of XRT Photon Counting mode data and 5 UVOT
images for GRB 170728A, 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 = 58.88831, +12.18148 which is equivalent
to:

RA (J2000): 03h 55m 33.19s
Dec (J2000): +12d 10' 53.3"

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

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

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


GRB_name: GRB170728A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21370
SUBJECT: GRB 170728A: Swift-BAT refined analysis 
DATE:    17/07/28 22:55:07 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

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

Using the data set from T-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 170728A (trigger #765008)
(Cannizzo et al., GCN Circ. 21367).  The BAT ground-calculated position is
RA, Dec = 58.901, 12.169 deg which is
  RA(J2000)  =  03h 55m 36.3s
  Dec(J2000) = +12d 10' 07.3"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 73%.

The mask-weighted light curve shows a weak pulse that starts at ~T0 and ends
at ~T+1.5. There is no evidence of extended emission. T90 (15-350 keV)
is 1.25 +- 0.23 sec (estimated error including systematics).

The time-averaged spectrum from T+0.17 to T+1.56 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index -0.49 +- 1.81,
and Epeak of 38.6 +- 7.3 keV (chi squared 51.37 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 7.1 +- 1.4 x 10^-8 erg/cm2
and the 1-sec peak flux measured from T+0.20 sec in the 15-150 keV band is
1.1 +- 0.2 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 2.02 +- 0.26 (chi squared 60.76 for 57 d.o.f.).  All the quoted errors
are at the 90% confidence level.

The spectrum is on the very soft end of the BAT-detected short GRB, only
a handful of BAT-detected short GRBs have comparable hardness ratio as
this burst (Lien & Sakamoto et al. 2016).

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/765008/BA/


GRB_name: GRB170728B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21371
SUBJECT: GRB 170728B: Swift detection of a short burst
DATE:    17/07/28 23:24:58 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

S. B. Cenko (GSFC), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), A. Cholden-Brown (PSU),
J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester) and M. H. Siegel (PSU) report on behalf of
the Swift Team:

At 23:03:19 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 170728B (trigger=765130).  Due to an observing constraint,
Swift executed a 6-min delayed slew to the burst.  The BAT on-board calculated
location is RA, Dec 238.044, +70.142, which is 
   RA(J2000)  =  15h 52m 11s
   Dec(J2000) = +70d 08' 32"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a single peak
with a duration of about 1 sec.  The peak count rate
was ~5500 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 23:11:08.2 UT, 468.9 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 237.9813, 70.1222 which
is equivalent to:
   RA(J2000)  = 15h 51m 55.52s
   Dec(J2000) = +70d 07' 19.9"
with an uncertainty of 2.2 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. 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 473 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 0.03. 

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


GRB_name: GRB170728B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21372
SUBJECT: GRB 170728B: TNG optical afterglow candidate
DATE:    17/07/29 01:16:51 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>

P. D'Avanzo (INAF-OAB), V. D'Elia (INAF/OAR & ASI/ASDC), M. Cecconi, H. Stoev (INAF-TNG) 
report on behalf of the CIBO collaboration: 

We observed the field of the short GRB 170728B (Cenko et al., GCN Circ. 21371) with the 3.6m 
Telescopio Nazionale Galileo (TNG) equipped with DOLoRes. Observations were carried out in 
the r-sdss filter. Observations started Jul 28 at 23:55:49 UT (~52.5 minutes after the burst) and 
consist in a single image lasting 300 seconds.

Inside the enhanced XRT position (http://www.swift.ac.uk/xrt_positions/) we detect a candidate optical 
afterglow. From preliminary photometry we estimate a magnitude r(AB)~20.6 (calibrated against nearby 
stars reported in the PAN-STARSS catalogue).


GRB_name: GRB170728B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21373
SUBJECT: GRB 170728B: position of the TNG optical counterpart
DATE:    17/07/29 01:49:24 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>

P. D'Avanzo (INAF-OAB), H. Stoev, M. Cecconi (INAF-TNG, V. D'Elia (INAF/OAR & ASI/ASDC) 
report on behalf of the CIBO collaboration: 

We report here the position of the optical afterglow candidate of the short GRB 170728B 
(Dâ€™Avanzo et al. GCN Circ. 21372). 

The source position is:

RA (J2000): 15:51:55.47
Dec (J2000): +70:07:21.1
+/- 0.3â€. 

We apologize for the delay in sending this information. 


GRB_name: GRB170728B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21374
SUBJECT: GRB 170728B: NOT optical afterglow confirmation
DATE:    17/07/29 02:14:13 GMT
FROM:    Kasper Elm Heintz at Univ. of Iceland and DARK/NBI  <heintz@dark-cosmology.dk>

K. E. Heintz (Univ. Iceland and DARK/NBI), N. R. Tanvir (Univ. Leicester), D. A. Perley (LJMU) and R. T. Rasmussen (NOT) report on behalf of a larger collaboration:

We observed the field of the short GRB 170728B (Cenko et al., GCN 21371) using the ALFOSC instrument equipped at the 2.56-m Nordic Optical Telescope (NOT). We obtained a single image with the SDSS r-band consisting of a 60 s exposure at 00:10:53 UT on 29 July, 2017  (i.e., 67.3 minutes after the burst). We confirm the presence of the optical afterglow (P. D'Avanzo et al., GCN 21372/21373) and from the single image we measure a magnitude of r(AB) = 20.9 +/- 0.1 mag calibrated against nearby stars from the Pan-STARRS survey. 

In addition, we obtained spectroscopy of the afterglow consisting of 3x1200 s exposures using grism no. 4, covering a spectral wavelength range of 3200 â€” 9600 Ã…, and a slit width of 1.3 arcsec. The trace is faint and at this point we can not robustly determine a redshift. A separate GCN will be submitted later based on the reduced spectroscopic data.

The observations were carried out under good weather conditions at an airmass of ~ 1.6 and a measured seeing of 0.74 arcsec.


GRB_name: GRB170728B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21375
SUBJECT: GRB 170728B: LT afterglow confirmation
DATE:    17/07/29 04:50:11 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

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

We began observing Swift GRB 170728B (Cenko et al. GCN 21371) on July 
28, 23:06:47 UT (208 seconds since the GRB trigger) with 2-m Liverpool 
Telescope with RINGO3 polarimeter and IO:O camera in the SDSS R filter. 
We clearly detect the optical counterpart (D'Avanzo et al. GCN 21373; 
Heintz et al. GCN 21374) with r'=20.43 +- 0.12 mag in a 6x10s frame at a 
mid time of 36.5 minutes since GRB, as calibrated against nearby 
Pan-STARRS1 sources.


GRB_name: GRB170728B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21376
SUBJECT: GRB 170728B: Swift-XRT refined Analysis
DATE:    17/07/29 05:05:26 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

V. D'Elia (ASDC), S. J. LaPorte (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. Melandri
(INAF-OAB) and S.B. Cenko report on behalf of the Swift-XRT team:

We have analysed 7.3 ks of XRT data for GRB 170728B (Cenko et al. GCN
Circ. 21371), from 454 s to 14.4 ks after the  BAT trigger. The data
comprise 231 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 best available XRT position  (using the promptly downlinked
event data, the XRT-UVOT alignment and matching UVOT field sources to
the USNO-B1 catalogue) is RA, Dec = 237.9806, 70.1227 which is
equivalent to:

RA (J2000): 15 51 55.35
Dec(J2000): +70 07 21.7

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

The light curve can be modelled with an initial power-law decay with an
index of alpha=0.66 (+0.08, -0.12), followed by a break at T+1874 s to
an alpha of 1.20 (+/-0.07).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.94 (+/-0.12). The
best-fitting absorption column is  1.7 (+0.5, -0.4) x 10^21 cm^-2, in
excess of the Galactic value of 3.2 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.81 (+/-0.08) and a
best-fitting absorption column of 2.5 (+/-0.3) x 10^21 cm^-2. The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 4.1 x 10^-11 (5.3 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      2.5 (+/-0.3) x 10^21 cm^-2
Galactic foreground: 3.2 x 10^20 cm^-2
Excess significance: 11.6 sigma
Photon index:      1.81 (+/-0.08)

If the light curve continues to decay with a power-law decay index of
1.20, the count rate at T+24 hours will be 0.043 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.8 x
10^-12 (2.3 x 10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00765130.

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


GRB_name: GRB170728B
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21377
SUBJECT: GRB 170728B: Enhanced Swift-XRT position
DATE:    17/07/29 05:33:24 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 7030 s of XRT Photon Counting mode data and 10 UVOT
images for GRB 170728B, 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 = 237.98125, +70.12230 which is equivalent
to:

RA (J2000): 15h 51m 55.50s
Dec (J2000): +70d 07' 20.3"

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

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

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


GRB_name: GRB170728A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21378
SUBJECT: GRB 170728A: Swift-XRT refined Analysis
DATE:    17/07/29 07:03:35 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. Melandri (INAF-OAB), P. D'Avanzo
(INAF-OAB) and J.K. Cannizzo report on behalf of the Swift-XRT team:

We have analysed 4.8 ks of XRT data for GRB 170728A (Cannizzo et al.
GCN Circ. 21367), from 84 s to 22.2 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. 21368).

The light curve can be modelled with a power-law decay with a decay
index of alpha=0.89 (+/-0.07).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.22 (+0.32, -0.25). The
best-fitting absorption column is  2.7 (+1.1, -0.4) x 10^21 cm^-2,
consistent with the Galactic value of 2.3 x 10^21 cm^-2 (Willingale et
al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux
conversion factor deduced from this spectrum  is 3.3 x 10^-11 (5.3 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      2.7 (+1.1, -0.4) x 10^21 cm^-2
Galactic foreground: 2.3 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:      2.22 (+0.32, -0.25)

If the light curve continues to decay with a power-law decay index of
0.89, 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 9.1 x
10^-14 (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/00765008.

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


GRB_name: GRB170714A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21379
SUBJECT: GRB170714A: XMM observation of the afterglow
DATE:    17/07/29 08:33:11 GMT
FROM:    Luigi Piro at INAF  <luigi.piro@iaps.inaf.it>

B. Gendre (UVI, USA), L. Piro (IAPS/INAF, Italy), E. Troja (GSFC, USA), R. 
Ricci (INAF/IRA-Bologna), M. Wieringa (ATNF,CSIRO), K. Bannister 
(ATNF,CSIRO) report:

We observed the field of GRB 170714A (D'Ai et al., GCN 21340) with 
XMM-Newton between 370,993 and 506,293 seconds post-trigger under our XMM 
program on ultralong GRBs (PI: Piro).

The X-ray afterglow is clearly visible during the whole observation, at 
the position:

RA: 2h17m24.02s
DEC: +1d59'28.51"

with an error of 1.3" (statistic + systematic, 90% confidence),
consistent with the position of the optical counterpart (de Ugarte Postigo 
et al. GCN 21346) and of XRT (Evans et al. GCN 21341).

The observed mean X-ray flux(0.3-10 keV) is 3.7e-14 erg/s/cm2

We thank the ESA and XMM SOC staff for performing this TOO trigger.


GRB_name: GRB170728B
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21380
SUBJECT: GRB 170728B: Fermi-LAT detection
DATE:    17/07/29 13:03:36 GMT
FROM:    Manal Yassine at IN2P3/LUPM/CNRS  <manal.yassine@lupm.in2p3.fr>

M. Yassine (LUPM,CNRS,IN2P3) and J. L. Racusin (NASA/GSFC) report on 
behalf of the Fermi-LAT team:

On July 28, 2017, Fermi-LAT detected high-energy emission from GRB 170728B,
which triggered the Fermi-GBM (trigger 522975804) at 23:33:32 UT July, 
28 2017. This burst was also detected by Swift (Cenko et al., GCN Circ. 
21371).

The best LAT on-ground location is found to be

RA, Dec 238.97, 69.74 (degrees, J2000)

with an error radius of 0.53 deg (90% containment, statistical error only).
This was 30 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 is spatially and temporally correlated
with the GBM emission with high significance.
More than 10 photons above 100 MeV are observed within 100 seconds.
The highest-energy photon is a 0.6 GeV event which is
observed 9.3 seconds after the GBM trigger.

The Fermi-LAT point of contact for this burst is
Manal Yassine (manal.yassine@lupm.in2p3.fr).

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: GRB170728B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21381
SUBJECT: GRB 170728B: I-band detection from 1.5m OSN 
DATE:    17/07/29 14:31:54 GMT
FROM:    Luca Izzo at IAA-CSIC  <Luca.Izzo@ICRA.it>

L. Izzo, D.A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), C. C. Thoene (HETH/IAA-CSIC) and A. Sota (IAA-CSIC) report on behalf of a larger collaboration:

We observed the field of GRB 170728B (Cenko et al., GCN 21371) with the 1.5m OSN telescope of the Sierra Nevada Observatory (Granada, Spain). Observation consisted of a series of 300 s Ic-band exposures, starting at 00:06:02.7 UT (1.05 hr after the burst). The afterglow is detected at a position consistent with the one reported by Dâ€™Avanzo et
al., (GCN 21373).

In the combination of the first 7x300s exposures we measure a magnitude of Ic(Vega) = 19.8+/- 0.2 as compared to USNO-B1 stars.


GRB_name: GRB170728A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21382
SUBJECT: GRB 170728A: LCO observations
DATE:    17/07/29 14:47:33 GMT
FROM:    Antonino Cucchiara at UVI  <antonino.cucchiara@uvi.edu>

A. Cucchiara, D. Morris (U. of Virgin Islands), and
C. Guidorzi (U. Ferrara), reports on behalf of a larger
collaboration:

"On July 28.38 UT  (T_0 +2.1h) we began observing the center
of the field of GRB 170728A (Cannizzo et al. GCN 21367,
Evans et al. GCN 21368) using the Las Cumbres Observatory
1m telescope in Cerro Tololo.
We performed a series of 4x240s observations in R and Ic band
for a total of 16 minutes on sky in each filter at average
airmass of 1.8. Further observations were requested in Sloane
i' filter for a total of 360s.

In the full combined R and I+i' stacks we identified no optical
counterpart within the center of Swift-XRT refined position
(Evans et al. GCN 21368) at the following 3-sigma limits:

R > 18.9 mag
I > 18.4 mag

These magnitudes are calibrated against nearby USNO-B1 sources,
and are not corrected for Galactic extinction."


GRB_name: GRB170728B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21383
SUBJECT: GRB 170728B: Fermi GBM detection
DATE:    17/07/29 15:47:09 GMT
FROM:    Matthew Stanbro at UAH/Fermi  <mcs0001@uah.edu>

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

"At 23:03:19.43 UT on 28 July 2017, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 170728B (trigger 522975804 / 170728961)
which was also detected by the Swift/BAT (S. B. Cenko et al. 2017, GCN
21371)
and Fermi LAT (M. Yassine et al. 2017, GCN 21380). The GBM on-ground
location
is consistent with the Swift position.

The Swift/BAT reported a short GRB in GCN 21371. Fermi GBM sees the
initial short peak at trigger time but is followed up by several peaks up
the ~50s later.

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 best location is 30 degrees.

The GBM light curve consists of several episodes
with a duration (T90) of about 46 s (50-300 keV).
The time-averaged spectrum from T0-.90 s to T0+47.23 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.10 +/- 0.10 and
the cutoff energy, parameterized as Epeak, is 175 +/- 26 keV

The event fluence (10-1000 keV) in this time interval is
(4.59 +/- 0.34)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.13 s in the 10-1000 keV band
is 12.7 +/- 0.32 ph/s/cm^2.

A Band function fits the spectrum equally well
with Epeak= 124 +/- 30 keV, alpha = -0.93 +/- 0.19 and beta = -2.12 +/-
0.22.


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


GRB_name: GRB170728B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21384
SUBJECT: GRB 170728B, Swift-BAT refined analysis
DATE:    17/07/29 19:04:42 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),
S. B. Cenko (GSFC), J. R. Cummings (CPI),
H. A. Krimm (NSF/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+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 170728B (trigger #765130)
(Cenko et al., GCN Circ. 21371).  The BAT ground-calculated position is
RA, Dec = 238.019, 70.111 deg which is
  RA(J2000)  =  15h 52m 04.5s
  Dec(J2000) = +70d 06' 40.0"
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 5%.

The mask-weighted light curve shows a short multi-peaked structure from
~T-0.1 s to ~T+0.7 s, followed by some weak emission till ~T+50 s,
Fermi/GBM also reports emission till ~T+47 s (Stanbro et al., GCN Circ. 21383).
T90 (15-350 keV) is 47.7 +- 25.2 sec (estimated error including systematics).

The time-averaged spectrum for the short pulse from T-0.1 to T+0.7 sec is
best fit by a power law with an exponential cutoff.  This fit gives a photon
index -1.10 +- 1.71, and Epeak of 82.0 +- 24.2 keV (chi squared 51.71 for
56 d.o.f.).  For this model the total fluence in the 15-150 keV band is
6.2 +- 1.1 x 10^-7 erg/cm2. A fit to a simple power law gives a photon index
of 1.21 +- 0.24 (chi squared 61.25 for 57 d.o.f.).

The time-averaged spectrum for the extended emission from T+0.7 to T+50.6 sec is
best fit by a simple power-law model.  The power law index of the time-averaged
spectrum is 2.25 +- 0.57.  The fluence in the 15-150 keV band is
9.8 +- 3.9 x 10^-7 erg/cm2.

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/765130/BA/


GRB_name: GRB170728A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21386
SUBJECT: GRB 170728A: Swift/UVOT Detection
DATE:    17/07/29 21:09:59 GMT
FROM:    Sam LaPorte at PSU  <sjl5346@psu.edu>

GRB 170728A: Swift/UVOT Detection

S. J. Laporte (PSU) 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 170728A
74 s after the BAT trigger (Cannizzo et al., GCN Circ. 21367).
A fading source consistent with the XRT position
(Goad et al. GCN Circ. 21368)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  03:55:33.17 =  58.88819 (deg.)
    Dec (J2000) = +12:10:54.7  =  12.18187 (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             70            219          147         19.20+-0.17   
white             70           4048          342         19.93+-0.18
v                 4264         5808          267        >19.1
b                 3655        11916          345        >19.7
u                  287        22167         1283        >20.0
w1                6020        21852         1105        >20.1
m2                5814        16112         1082        >20.6
w2                4059         4259          197        >19.6

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.24 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB170728B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21387
SUBJECT: GRB 170728B iTelescope observation
DATE:    17/07/29 23:19:08 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

Y. Kitaoka, T. Sakamoto (AGU)

We observed the field of GRB 170728B detected by Swift (Cenko et al., GCN Circ. 21371)
with the iTelescope.Net (http://www.itelescope.net) T16 (Takahashi TOA-150) telescope
located at the AstroCamp Observatory (Nerpio, Spain).  20 images of 60 sec exposures
were taken in the R filter starting from July 28  23:03:19 (UT) about  36 mimute after
the trigger and stopped on July 29 00:17:48 (UT).  We do not detect the optical afterglow
both in the individual images and the stacked image at the X-ray afterglow position.
The estimated five sigma upper limit of the combined image (total exposure of 1200 sec)
is ~15.8 using the USNO-B1 catalog.


GRB_name: GRB170728B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21388
SUBJECT: GRB 170728B: Swift/UVOT Upper Limits
DATE:    17/07/30 01:46:56 GMT
FROM:    Sam LaPorte at PSU  <sjl5346@psu.edu>

GRB 170728B: Swift/UVOT Upper Limits

S. J. Laporte (PSU) and S. B. Cenko (GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 170728B
473 s after the BAT trigger (Cenko et al., GCN Circ. 21371).
No optical afterglow consistent with the optical position
(D'Avanzo et al. GCN Circ. 21373)
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           473          623          147         >19.8
white              473         7867          908         >20.8
v                  630         8278          627         >19.6
b                  728        14417         1117         >21.3
u                  703        13868         1276         >21.2
w1                 679        19251         2000         >21.6
m2                6847        18681         1279         >22.1
w2                6437         8073          393         >21.5

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: GRB170728B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21389
SUBJECT: GRB 170728B: COATLI Observations And Confirmation of Fading
DATE:    17/07/30 02:20:58 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), Carlos
RomÃ¡n-ZÃºÃ±iga (UNAM), and William H. Lee (UNAM) report:

We observed the field of the short GRB 170728B (Cenko et al., GCN Circ.
21371) with the COATLI 50-cm telescope and interim imager (Watson et al.
2016, Proc. SPIE, 9908, 50) at the Observatorio AstronÃ³mico Nacional on
the Sierra de San Pedro MÃ¡rtir from 2017-07-29 04:21 to 08:19 obtaining
a total of 2.76 hours of observation in the clear filter.

We detect the source reported by Dâ€™Avanzo et al. (GCN Circ. 21372).
Calibrating with respect to the USNO-B1 catalog, we estimate a
preliminary magnitude of

R = 22.40 +/- 0.16.

This magnitude is in the USNO-B1 Vega system and is corrected for
Galactic extinction in the direction of the GRB.

The source has faded by around two magnitudes between the observations
in the first hour or so (Dâ€™Avanzo et al., GCN Circ. 21372; Heintz et al,
GCN Circ. 21374; and Guidorzi et al., GCN Circ. 21375) and our
observations. This confirms that the source is the optical transient
associated with the GRB.

We thank the COATLI technical team (Fernando Ãngeles, Oscar Chapa,
Salvador Cuevas, Alejandro Farah, Jorge Fuentes, RosalÃ­a Langarica,
Fernando QuirÃ³s, and Carlos Tejada) and the staff of the Observatorio
AstronÃ³mico Nacional.


GRB_name: GRB170730A
Detection_method: IBAS
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21390
SUBJECT: IBAS weak Alert nr.7881: possible GRB 170730A
DATE:    17/07/30 07:45:59 GMT
FROM:    Diego Gotz at CEA  <diego.gotz@cea.fr>

D.Gotz (CEA Saclay) on behalf of the IBAS Localization Team reports:

the weak IBAS Alert nr. 7881 corresponds to a weak transient source lasting about 100 s, starting at 00:09:32 UT on July 30th 2017, localized at

R.A: 245.3407 deg
Dec: -60.8832 deg

with an unceratinty of 2.5 arc min (90% c.l.).

We prliminarly classify it as a GRB, but we cannot exclude that it is a new Galactic source due to its low Galactic latitude.

Futher analysis is on-going.

This message can be cited.


GRB_name: GRB170728B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21391
SUBJECT: GRB 170728B: MASTER-IAC first minute  short GRB early OT detection
DATE:    17/07/30 13:25:56 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, D.Kuvshinov, A.V.Krylov,
I.Gorbunov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University, Sternberg Astronomical Institut of MSU

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

R.Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA),
National University of San Juan, Argentina

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

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

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

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

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


MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in IAC was pointed to the  GRB170728B (Cenko et al., GCN Circ.
#21371)  28 sec after notice time 
and 39 sec after trigger time at 2017-07-28 23:04:01 UT. On our first (10s 
exposure)  set we  found optical transient   within  SWIFT XRT error-box ( 
D'Elia et al., GCN #21376; ) in two polarizations! 
The 5-sigma upper limit has been about 16.9 mag
We 100% found faiding OT  on  first 10 minutes  images with m ~ 16.5  up 
to 18 mag.

RA, DEC  = 15h 51m 55s.5 , +70d 7m 19s.3
Error = +- 1.4 arcsec

The faiding OT may be coincide with D'Avanzo et al. position  (GCN 
#21372) and Heintz et al., (GCN #21374) and Izzo et al., (GCN #21381) and

The observations made on zenit distance = 47 degrees, galaxy latitude b = 
40 degree.
The moon (34 % bright part) is  8 degrees above the horizon. The distance 
between  moon and  object is 78
The sun  altitude  is -33.7 degree.
The error box can be observed till sunrise at 2017-07-29 06:25:17.

The message may be cited.


GRB_name: GRB170730A
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21392
SUBJECT: GRB170730A detecetd by INTEGRAL. Refined analysis
DATE:    17/07/30 14:19:45 GMT
FROM:    Sandro Mereghetti at IASF-Milano/INAF  <sandro@iasf-milano.inaf.it>

S.Mereghetti (IASF-Milano), D.Gotz (CEA, Saclay), C.Ferrigno, E.Bozzo, and 
J.Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report:

further analysis of the possible GRB 170730A detected as a subtrheshold 
alert by IBAS in the IBIS/ISGRI data at 00:09:20 UT of July 30, 2017 (Gotz 
et al. GCN 21390) yields the refined coordinates (J2000):

R.A.= 245.2996 deg
DEC.= -60.8866  deg

with an uncertainty of 2 arcmin (90% c.l.).

The burst lasted about 500 s, with a peak flux of about 0.6 photons/cm2/s 
(20-200 keV, 1-s integration time) and a fluence in the same energy range 
of about 1e-6 erg/cmq. The time averaged spectrum is consistent with a 
power law with photon index ~2

A plot of the light curve will  be posted at
http://ibas.iasf-milano.inaf.it/IBAS_Results.html


GRB_name: GRB170728B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21393
SUBJECT: GRB 170728B: BOOTES-2/TELMA optical detection during the extended gamma-ray phase
DATE:    17/07/30 17:00:39 GMT
FROM:    Alberto Castro-Tirado at Inst.de Astro. de Andalucia  <ajct@iaa.es>

A. J. Castro-Tirado (IAA-CSIC Granada & ISA-UMA MÃ¡laga), A. 
GonzÃ¡lez-RodrÃ­guez, Y. Hu, R. Cunniffe, J. C. Tello, B.-B. Zhang 
(IAA-CSIC Granada), A. CastellÃ³n, I. Carrasco (UMA MÃ¡laga), M. JelÃ­nek 
(ASU-CAS Ondrejov), S. Guziy (Nikolaev Univ.), S. B. Pandey (ARIES 
Nainital), S. Jeong (SKKU Seoul), M. D. Caballero-GarcÃ­a (ASU-CAS 
Prague), M. Wildi (Vermes Obs.) and P. KubÃ¡nek (IP-ASCR Prague), on 
behalf of a larger collaboration, report:

Following the detection of GRB 170728B by Swift (Cenko et al. GCNC 
21371), the TELMA 0.6m robotic telescope at the BOOTES-2 astronomical 
station at IHSM/UMA-CSIC in MÃ¡laga (Spain) pointed to the GRB location 
26 sec after the notice time and 40 sec after trigger time, i.e. at 
23:03:59 UT on July 28.

The first exposures (3 sec, unfiltered) were taken simultaneously to the 
extended gamma-ray emission phase (Stanbro et al. GCNC 21383, Ukwatta et 
al. GCNC 21384), confirming the optical transient within the Swift/XRT 
error box (D'Elia et al., GCNC 21376) being coincident with the optical 
afterglow position (D'Avanzo et al. GCN 21373) with magnitudes in the 
range reported by Lipunov et al. (GCNC et al. 21391) starting 2 sec 
after. A detailed analysis is ongoing.

This message can be quoted.

[GCN OPS NOTE(31jul17):  Per author's request, the date was corrected
from "July 2" to "July 28"]


GRB_name: GRB170728B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21394
SUBJECT: GRB 170728B: Optical observations at Crni Vrh
DATE:    17/07/30 20:13:20 GMT
FROM:    Bojan Dintinjana at OCV  <bojan.dintinjana@fmf.uni-lj.si>

B. Dintinjana and H. Mikuz on behalf of PIKA observing program at Crni 
Vrh Observatory:

We observed the afterglow of GRB 170728B (Cenko et al., GCN Circ. 21371) 
with 60 cm Cichocki robotic telescope at Crni Vrh Observatory, Slovenia. 
The series of twenty-six 60 second exposures with Rc filter started at 
23:04:41UT, 81 seconds after the burst. We confirm optical afterglow at 
coordinates reported by DAvanzo et al. (GCN Circ. 21372, 21373).

Photometry results are given in table below. The table contains the mid 
time of exposure in MJD, time since the Swift GRB detection to the 
middle of exposure in seconds, Rc magnitude and photometric error. The 
magnitudes are derived using comparison stars from the APASS catalog. 
The 3-sigma limiting magnitude in Rc filter is around magnitude 20.2  0.2.
The light curve of the GRB 170728B:
http://www.observatorij.org/vstars/GRB170728B/GRB170728B.png

MJD t-T0 Rc err
(s) (mag) (mag)
-------------------------------------
57962.961574 81 17.410 0.04
57962.962407 153 17.867 0.05
57962.963252 226 18.077 0.06
57962.964097 299 18.412 0.08
57962.964931 371 18.638 0.10
57962.965775 444 18.830 0.11
57962.966620 517 18.827 0.11
57962.967454 589 19.123 0.14
57962.968299 662 19.054 0.13
57962.969144 735 19.142 0.14
57962.969977 807 19.181 0.15
57962.970822 880 19.217 0.16
57962.971667 953 19.714 0.26
57962.972512 1026 19.505 0.22
57962.973345 1098 19.507 0.20
57962.974190 1171 19.586 0.23
57962.975023 1243 19.674 0.27
57962.975868 1316 19.456 0.23
57962.976713 1389 19.981 0.35
57962.977558 1462 19.734 0.25
57962.978391 1534 20.227 0.42
57962.979236 1607 19.736 0.25
57962.980081 1680 19.878 0.32
57962.980926 1753 20.200 0.38
57962.981759 1825 19.519 0.21
57962.982604 1898 19.913 0.31
-------------------------------------


GRB_name: GRB170728B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21395
SUBJECT: GRB 170728B: VLA radio afterglow detection
DATE:    17/07/31 04:27:16 GMT
FROM:    Wen-fai Fong at U of Arizona  <wfong@email.arizona.edu>

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

"We observed the position of GRB 170728B (Cenko et al., GCN 21371; Yassine
et al., GCN 21380; Stanbro & Meegan, GCN 21383) with the Karl G. Jansky
Very Large Array (VLA) beginning on 2017 Jul 29.075 UT (2.75 hr post-burst)
at a mean frequency of 6 GHz. We obtained a second set of observations
beginning on 2017 Jul 29.811 UT (20.4 hr post-burst) at mean frequencies of
6 and 10 GHz.

We do not detect any radio counterpart in our first set of observations at
2.75 hr, while we clearly detect a radio source in our second set of
observations at both frequencies at 20.4 hr at the position:

RA(J2000) = 15:51:55.45
Dec(J2000) = +70:07:21.2

with an uncertainty of 0.2" in each coordinate. This position is coincident
with the reported optical source (D'Avanzo et al., GCN 21372, GCN 21373;
Heintz et al., GCN 21374; Guidorzi et al., GCN 21375; Watson et al., GCN
21389). Given the rapid variability and positional coincidence with the
X-ray (Osborne et al., GCN 21377) and optical afterglows, we consider this
to be the radio afterglow of GRB 170728B.

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


GRB_name: GRB170714A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21396
SUBJECT: GRB 170714A: Chandra observations
DATE:    17/07/31 12:35:17 GMT
FROM:    Eleonora Troja at GSFC  <eleonora.troja@nasa.gov>

E. Troja (NASA/UMCP), L. Piro (INAF/IASF), B. Gendre (UVI)
report on behalf of a larger collaboration:

We observed the field of the ultralong GRB 170714A (D'Ai et al.,
GCN 21340) with the Chandra X-ray Observatory beginning on 2017
Jul 28.67 UT (14 days post-burst) for a total exposure of 14.9 ks.
We clearly detect the GRB counterpart with coordinates:

RA(J2000) = 02:17:23.97
Dec(J2000) = +01:59:29.72

with a 68% uncertainty of 0.5 arcsec. This position is consistent with
the XRT position (http://www.swift.ac.uk/xrt_positions/00762535/), and
the optical source reported by de Ugarte Postigo et al. (GCN 21346).
By adopting the spectral parameters of the Swift/XRT analysis (D'Avanzo
et al., GCN 21343), we estimate an average X-ray flux of
~1.1E-14 erg/cm2/s during our observation. This is consistent with a
late-time power-law decay of slope ~-1.

We thank Andrea Prestwich, Belinda Wilkes and the CXC staff for
rapidly scheduling this observation.


GRB_name: GRB170726A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21397
SUBJECT: GRB 170726A: AstroSat CZTI detection
DATE:    17/07/31 14:44:12 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

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

Analysis of Astrosat CZTI data showed the detection of a long-duration GRB 170726A, which was also detected by Insight-HXMT (Li et al., GCN 21366), SPI-ACS (trig time: 2017-07-26 19:02:59.51) and
Fermi/GBM (trig time: 2017-07-26 19:02:59.976).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with the strongest peak at 19:03:00.976 UT, ~1 s after the Insight-HXMT Trigger. The measured peak count rate is 475.9 cts/s above the background in combined data of four quadrants, with a total of 5477 cts. The local mean background count rate was 377.1 cts/s. Using cumulative rates, we measure a T90 of 39.6 s.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

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: GRB170728B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21398
SUBJECT: Konus-Wind observation of GRB 170728B
DATE:    17/07/31 15:51:16 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 GRB 170728B (Swift-BAT trigger 765130:
Cenko et al., GCN 21371; Ukwatta et al., GCN 21384;
Fermi-LAT detection: Yassine et al., GCN 21380;
Fermi-GBM observation: Stanbro et al., GCN 21383)
triggered Konus-Wind at T0=82998.412 s UT (23:03:18.412).

The burst light curve shows an initial short multi-peaked structure
with a duration of ~0.5 s, followed by a weaker emission
seen up to ~48 s. The emission is seen up to ~2 MeV.

As observed by Konus-Wind, the burst
had a fluence of 3.96(-0.75,+0.93)x10^-6 erg/cm2,
and a 64-ms peak flux, measured from T0-0.016 s,
of 4.38(-0.91,+0.93)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 2 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -1.13(-0.37,+0.45)
and Ep = 160(-43,+103) keV (chi2 = 66/62 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -3.1
(chi2 = 66/61 dof)

The spectrum near the maximum count rate
(measured from T0+0.000 to T0+0.256 s)
is best fit in the 20 keV - 2 MeV range
by a power law with exponential cutoff model
with  alpha = -0.22(-0.33,+0.39)
and Ep = 166(-22,+26) keV (chi2 = 22/36 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 = 22/35 dof)

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB170728_T82998/

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


GRB_name: GRB170728B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21399
SUBJECT: GRB 170728B: Swift/UVOT Further Analysis
DATE:    17/07/31 19:31:50 GMT
FROM:    Sam LaPorte at PSU  <sjl5346@psu.edu>

GRB 170728B: Swift/UVOT Detection

S. J. LaPorte (PSU), S.W.K. Emery (MSSL), and S. B. Cenko (GSFC)
report on behalf of the Swift/UVOT team:

After detailed analysis of initial data reported in LaPorte and Cenko, 
GCN Circ. 21388, we do find a significant detection in initial optical 
filter exposures.

The Swift/UVOT began settled observations of the field of GRB 170728B
473 s after the BAT trigger (Cenko et al., GCN Circ. 21371).
A fading source consistent with the optical position
(D'Avanzo et al. GCN Circ. 21373)
is detected in the initial UVOT exposures.

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              876         1026          147         20.56 +/- 0.20
v                  630         8278          627         20.23 +/- 0.27
b                  728         2561          194         20.60 +/- 0.29
u                  703        13868         1276        >21.2
w1                 679        19251         2000        >21.6
m2                6847        18681         1279        >22.1
w2                6437         8073          393        >21.5

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: GRB170728B
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21401
SUBJECT: GRB 170728B: time correction to MASTER GCN Circular 21391   
DATE:    17/08/01 08:32:12 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

N.Tyurina, V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, 
A.V.Krylov, I.Gorbunov, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University, Sternberg Astronomical Institut of MSU

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

R.Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA),
National University of San Juan, Argentina

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

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

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

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

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

We found additional image in MASTER-IAC DataBase with more early time.
So the begining of our GCN Circular #21391 must be readed 
as:

MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in IAC was pointed to the  GRB170728B 19 sec after notice time 
and 30 sec after trigger time at 2017-07-28 23:03:49 UT. On our first (10s 
exposure)  image we found optical transient  within SWIFT 
error-box (Cenko et al., GCN Circ. #21371).
The 5-sigma upper limit has been about 16.6 mag

The message may be cited.


GRB_name: GRB160814A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21402
SUBJECT: GRB 160814A: Lomonosov BDRG gamma ray discovery
DATE:    17/08/01 17:01:35 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

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

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

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

A. J. Castro-Tirado
Instituto de Astrofisica de Andalucia (IAA-CSIC) and Universidad de Malaga, 
Spain


As a result of reprocessing, GRB160814A was found.
At 21:12:42 UT on 14 Aug 2016, the Lomonosov BDRG Gamma-ray Burst
Monitor (http://lomonosov.sinp.msu.ru/en/scientific-equipment-2/bdrg
[1]),
detected GRB160814A (Y. Kawakubo (AGU), GCN 19793):
total duration ~25s,the energy range 20-170 keV.

LC is available at:

https://downloader.sinp.msu.ru/static/grb_catalog/lc/grb_20160814_211242.png
[2]

More information is available at:
https://downloader.sinp.msu.ru/grb_catalog/ [3]
This Notice was ground-generated.



The message may be cited.


GRB_name: GRB170802A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21404
SUBJECT: GRB 170802A: Fermi GBM detection
DATE:    17/08/03 02:25:02 GMT
FROM:    Matthew Stanbro at UAH/Fermi  <mcs0001@uah.edu>

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

"At 15:18:24.80 UT on 02 August 2017, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 170802A (trigger 523379909 / 170802638).
The on-ground calculated location, using the GBM trigger
data, is RA = 52.3, DEC = -39.2, with an uncertainty
of 2.1 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 best location is 41 degrees.

The GBM triggered on a precursor that
was followed ~1 s later by a brighter peak. The
total duration (T90) was about 2 s (50-300 keV).
The time-averaged spectrum from T0-0.13 s to T0+2.24 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.80 +/- 0.08 and
the cutoff energy, parameterized as Epeak, is 952 +/- 200 keV.

The event fluence (10-1000 keV) in this time interval is
(2.70 +/- 0.11)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.41 s in the 10-1000 keV band
is 8.20 +/- 0.27 ph/s/cm^2.

A Band function fits the spectrum equally well
with Epeak= 670 +/- 163 keV, alpha = -0.70 +/- 0.11 and beta = -2.09 +/-
0.25.


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


GRB_name: GRB170803A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21405
SUBJECT: GRB 170803A: Swift detection of a burst with an optical counterpart
DATE:    17/08/03 17:42:50 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

S. J. LaPorte (PSU), A. Cholden-Brown (PSU), J. A. Kennea (PSU),
F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester),
D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and
M. H. Siegel (PSU) report on behalf of the Swift Team:

At 17:30:27 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 170803A (trigger=766081).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 174.950, -16.311 which is 
   RA(J2000) = 11h 39m 48s
   Dec(J2000) = -16d 18' 38"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a multiple-peaked
structure with a duration of about 5 sec.  The peak count rate
was ~15000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 17:32:27.0 UT, 120.1 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 174.93532, -16.31155 which is
equivalent to:
   RA(J2000)  = 11h 39m 44.48s
   Dec(J2000) = -16d 18' 41.6"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 50 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (3.54 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 3
(+2.47/-2.15) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 88 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 11:39:44.11 = 174.93381
  DEC(J2000) = -16:18:37.9  = -16.31052
with a 90%-confidence error radius of about 0.75 arc sec. This position is 6.1
arc sec. from the center of the XRT error circle. The estimated magnitude is
18.12 with a 1-sigma error of about  0.15. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.04. 

Burst Advocate for this burst is S. J. LaPorte (extragsam 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: GRB170803A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21406
SUBJECT: GRB 170803A: Fermi GBM observation
DATE:    17/08/03 23:03:54 GMT
FROM:    Peter Veres at UAH  <veresp@gmail.com>

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

"At 17:30:27.112 UT on 3 August 2017, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 170803A (trigger 523474232 / 170803729)
which was also detected by the Swift/BAT (LaPorte et al., GCN 21405).
The GBM on-ground location is consistent with the Swift position.


The angle from the Fermi LAT boresight at the GBM trigger time is 40 degrees.


The GBM light curve consists of a single pulse
with a duration (T90) of about 3.6 s (50-300 keV).
The time-averaged spectrum from T0-0.1 s to T0+2.2 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.71 +/- 0.12 and
the cutoff energy, parameterized as Epeak, is 154 +/- 13 keV.

The event fluence (10-1000 keV) in this time interval is
(1.65 +/- 0.076)E-6 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.1 s in the 10-1000 keV band
is 9.1 +/- 0.3 ph/s/cm^2.

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


GRB_name: GRB170803A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21407
SUBJECT: GRB 170803A: Enhanced Swift-XRT position
DATE:    17/08/04 01:08:11 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 2272 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 170803A, 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 = 174.93434, -16.31002 which is equivalent
to:

RA (J2000): 11h 39m 44.24s
Dec (J2000): -16d 18' 36.1"

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: GRB170803A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21408
SUBJECT: GRB 170803A: Swift-XRT refined Analysis
DATE:    17/08/04 03:59:45 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.
Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A.
Cholden-Brown (PSU) and S.J. LaPorte report on behalf of the Swift-XRT
team:

We have analysed 6.1 ks of XRT data for GRB 170803A (LaPorte et al. GCN
Circ. 21405), from 68 s to 30.1 ks after the  BAT trigger. The data
comprise 312 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. 21407).

The late-time light curve (from T0+5.6 ks) can be modelled with a
power-law decay with a decay index of alpha=1.00 (+/-0.28).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.86 (+0.13, -0.12). The
best-fitting absorption column is  1.3 (+/-0.4) x 10^21 cm^-2, in
excess of the Galactic value of 3.5 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 3.7 x 10^-11 (4.5 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.3 (+/-0.4) x 10^21 cm^-2
Galactic foreground: 3.5 x 10^20 cm^-2
Excess significance: 4.5 sigma
Photon index:      1.86 (+0.13, -0.12)

If the light curve continues to decay with a power-law decay index of
1.00, the count rate at T+24 hours will be 6.3 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.3 x
10^-13 (2.8 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/00766081.

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


GRB_name: GRB170804A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  21410
SUBJECT: GRB 170804A: Swift detection of a burst with optical counterpart
DATE:    17/08/04 12:13:26 GMT
FROM:    Jamie A. Kennea at PSU/Swift-XRT  <kennea@swift.psu.edu>

A. Cholden-Brown (PSU), D. N. Burrows (PSU),
P. A. Evans (U Leicester), J. A. Kennea (PSU), S. J. LaPorte (PSU),
A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester) and B. Sbarufatti (INAF-OAB/PSU) report on
behalf of the Swift Team:

At 12:01:37 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 170804A (trigger=766194).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 6.433, -64.748 which is 
   RA(J2000) = 00h 25m 44s
   Dec(J2000) = -64d 44' 52"
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 ~1400 counts/sec (15-350 keV), at ~5 sec after the trigger. 

The XRT began observing the field at 12:03:39.9 UT, 122.6 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 6.39106, -64.78341 which
is equivalent to:
   RA(J2000)  = 00h 25m 33.85s
   Dec(J2000) = -64d 47' 00.3"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 142 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 (1.79 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 2.4
(+3.30/-2.37) x 10^21 cm^-2 (90% confidence). 

The initial flux in the 2.5 s image was 5.37e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 131 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 00:25:34.45 = 6.39354
  DEC(J2000) = -64:47:03.0  = -64.78416
with a 90%-confidence error radius of about 0.63 arc sec. This position is 6.9
arc sec. from the center of the XRT error circle. The estimated magnitude is
19.01 with a 1-sigma error of about  0.15. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.02. 

Burst Advocate for this burst is A. Cholden-Brown (aaronb 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.)


