GRB 170728B
GCN Circular 21932
Subject
GRB 170728B: Kottamia R-band observation
Date
2017-09-27T06:13:52Z (8 years ago)
From
Yasser Hendy at NRIAG <y_hendy_yasser@yahoo.com>
TITLE:���� GCN CIRCULAR
NUMBER: ��
SUBJECT: GRB 170728B: Kottamia R-band observation
DATE:������ 17/09/27 6:09 GMT
FROM:������ Yasser Hendy at NRIAG�� <y_hendy_yasser@yahoo.com>
��
G. B. Ali, Y.H.M. Hendy, A. Takey, N. Essam, and A. Essam
National Research institute of Astronomy and Geophysics, NRIAG, Egypt
report on behalf of the Kottamia collaboration:
We observed the field of the short GRB 170728B: trigger=765130
(Cenko S. B. et al., GCN Circ. 21371) with the 1.88m telescope
of the KAO (Kottamia Astronomical Observatory), Egypt.
The observation was performed in the Rc-band at the Newtonian
camera (F4.8) and started at 2017-07-29 T18:11:19 UT
(~ 19.13 hours (0.8 day) after the burst).
We obtained four images in the Rc-band each one with 600s exposure
time.�� We clearly detected the optical afterglow (D'Avanzo et al., GCN Circ.
21372/21373; Heintz et al., GCN Circ. 21374; Guidorzi et al., GCN Circ. 21375;
Izzo et al., GCN Circ. 21381; Kitaoka et al., GCN Circ. 21387; Watson et al.,
GCN Circ. 21389; Dintinjana et al., GCN Circ. 21394; Volnova et al., GCN Circ. 21419).
We estimate a magnitude Rc 20.625 +/- 0.133, calibrated against nearby
USNO-B1.0 stars:
�� USNO-B1.0������ R2
1601-0108297�� 13.35
1600-0109901�� 13.61
1600-0109913�� 14.08
1601-0108263�� 14.58
1601-0108285�� 14.59
1601-0108292�� 14.71
1601-0108254�� 15.04
1600-0109911�� 15.42
1600-0109861�� 15.52
1601-0108199�� 15.66
1600-0109905�� 15.92
1600-0109885�� 15.97
-Yasser Hendy, on behalf of tthe Kottamia collaboration
��GRB followup team.
======================================================================
Dr. Yasser Hassan Mohamed�� Mohamed�� Hendy
National Research Institute of Astronomy & Geophysics (NRIAG),
Astronomy Department, 11421 Helwan, Cairo, Egypt.
Phone: +202 25560645���������� Fax: +202 25548020���������� Mobile: +20 1007580213������ +20 1145385285��������
Email: y_hendy_yasser@yahoo.com�� yasserhendy@nriag.sci.eg���� yasserhendy@mail.ru
Homepage:������ NRIAG������������ ResearchGate�������� GoogleScholar���������� Facebook���������� vk
======================================================================
GCN Circular 21466
Subject
GRB 170728B: 15 GHz upper limits from AMI
Date
2017-08-11T18:16:52Z (8 years ago)
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 the
short GRB 170728B (Cenko et al., GCN 21371) as part of the 4pisky
program, and subsequent follow up observations were obtained up to 3
days post-burst. Our observations at 15 GHz on 2017 Jul 29.00, Jul
29.80, Jul 30.80 and Jul 31.76 (UT) do not reveal any radio source at
the XRT location (Osborne et al., GCN 21377), with 3sigma upper limits
of 258 uJy, 201 uJy, 171 uJy and 108 uJy respectively. This upper limit
is consistent with the radio afterglow detection on 2017 Jul 29.81
reported by Fong et al. (GCN 21395; much fainter than 300 uJy at 6 GHz).
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/.
GCN Circular 21441
Subject
GMRT upper limit on the radio afterglow of GRB 170728B
Date
2017-08-10T06:40:18Z (8 years ago)
From
Poonam Chandra at TIFR <poonam@ncra.tifr.res.in>
Poonam Chandra & A. J. Nayana (NCRA-TIFR, India) report:
We observed the short hard burst GRB 170728B (Cenko et al., GCN Circ. 21371) with the Giant Metre Wave Radio Telescope (GMRT) at 1390 MHz band on 2017 August 09.61 UT, i.e. 11.65 days after the burst. We do not see any significant radio emission at the burst position (D���Avanzo et al. GCN Circ. 21373). The 3-sigma upper limit on the GRB radio flux density is 140 uJy.
We thank the GMRT staff for scheduling these observations.
GCN Circular 21419
Subject
GRB 170728B: TShAO, SAO RAS and AbAO optical observations
Date
2017-08-07T10:23:04Z (8 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Volnova (IKI), A. Kusakin (Fesenkov Astrophysical Institute), A.S.
Moskvitin (SAO RAS), O.I. Spiridonova (SAO RAS), R. Inasaridze (AbAO), I.
Reva (Fesenkov Astrophysical Institute), E. Mazaeva (IKI), A. Pozanenko
(IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of the Swift GRB 170728B (Cenko et al., GCN 21371)
with Zeiss-1000 of SAO RAS (July 29, August 4,5 ), AS-32 telescope of AbAO
(July 29) and Zeiss-1000 telescope of Tien Shan Astronomical Observatory
(July 30,31 August 1,6). Below we report the photometry of the optical
afterglow (D'Avanzo et al., GCNs 21372, 21373; Heintz et al., GCN 21374;
Guidorzi et al., GCN 21375) and upper limits of our observations.
Preliminary photometry is following:
Date UT start t-T0 Filter Exp. OT Err. UL Telescope
(mid, days) (s) (3 sigma)
2017-07-29 00:41:51 0.07228 R 600 n/d n/d 18.6 Z-1000 SAO
2017-07-29 17:27:49 0.79594 CR 43*60 n/d n/d 20.4 AS-32 AbAO
2017-07-30 16:12:56 1.79815 R 97*120 21.93 0.25 22.1 Z-1000 TSHAO
2017-08-01 15:12:51 3.72304 R 60*120 n/d n/d 21.6 Z-1000 TSHAO
2017-08-04 00:41:51 5.98081 R 41*300 22.6 0.23 22.8 Z-1000 SAO
The photometry is based on nearby USNO-B1.0 stars
1601-0108291 15:52:31.54 +70:09:31.7 R2 17.95
1601-0108289 15:52:28.99 +70:09:26.3 R2 18.08
1601-0108260 15:51:57.87 +70:09:53.8 R2 16.87
1601-0108254 15:51:50.88 +70:08:41.2 R2 15.04
1601-0108262 15:52:03.24 +70:07:32.0 R2 16.01
Coordinates of the afterglow obtained from observation on July 30 are
(J2000)
15 51 55.5179 +70 07 21.123 with uncertainties on both coordinates of 0.2
arces which is compatible with coordinates of TNG (D'Avanzo et al., GCN
21373) and VLA (Fong et al., GCN 21395). The finding chart can be found in
http://grb.rssi.ru/GRB170728B/GRB170728B_TShAO_R_170730.png
The light curve of the afterglow based on observations above and photometry
reported in GCNs (Dintinjana et al., GCN 21394; Watson GCN 21389; D'Avanzo
et al., GCN 21372; Heintz et al., GCN 21374; Guidorzi et al., GCN 21375)
can be found in
http://grb.rssi.ru/GRB170728B/GRB170728B_lc+GCNs_v2.png
Based on our observation on July, 30 (~ 1.8 days after burst onset) one can
suggest that the OT experienced rebrightening at that epoch.
GCN Circular 21401
Subject
GRB 170728B: time correction to MASTER GCN Circular 21391
Date
2017-08-01T08:32:12Z (8 years ago)
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.
GCN Circular 21399
Subject
GRB 170728B: Swift/UVOT Further Analysis
Date
2017-07-31T19:31:50Z (8 years ago)
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).
GCN Circular 21398
Subject
Konus-Wind observation of GRB 170728B
Date
2017-07-31T15:51:16Z (8 years ago)
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.
GCN Circular 21395
Subject
GRB 170728B: VLA radio afterglow detection
Date
2017-07-31T04:27:16Z (8 years ago)
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."
GCN Circular 21394
Subject
GRB 170728B: Optical observations at Crni Vrh
Date
2017-07-30T20:13:20Z (8 years ago)
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 D�Avanzo 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
-------------------------------------
GCN Circular 21393
Subject
GRB 170728B: BOOTES-2/TELMA optical detection during the extended gamma-ray phase
Date
2017-07-30T17:00:39Z (8 years ago)
From
Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>
A. J. Castro-Tirado (IAA-CSIC Granada & ISA-UMA M��laga), A.
Gonz��lez-Rodr��guez, Y. Hu, R. Cunniffe, J. C. Tello, B.-B. Zhang
(IAA-CSIC Granada), A. Castell��n, I. Carrasco (UMA M��laga), M. Jel��nek
(ASU-CAS Ondrejov), S. Guziy (Nikolaev Univ.), S. B. Pandey (ARIES
Nainital), S. Jeong (SKKU Seoul), M. D. Caballero-Garc��a (ASU-CAS
Prague), M. Wildi (Vermes Obs.) and P. Kub��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 M��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"]
GCN Circular 21391
Subject
GRB 170728B: MASTER-IAC first minute short GRB early OT detection
Date
2017-07-30T13:25:56Z (8 years ago)
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.
GCN Circular 21389
Subject
GRB 170728B: COATLI Observations And Confirmation of Fading
Date
2017-07-30T02:20:58Z (8 years ago)
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
Rom��n-Z����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 Astron��mico Nacional on
the Sierra de San Pedro M��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 D���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 (D���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 ��ngeles, Oscar Chapa,
Salvador Cuevas, Alejandro Farah, Jorge Fuentes, Rosal��a Langarica,
Fernando Quir��s, and Carlos Tejada) and the staff of the Observatorio
Astron��mico Nacional.
GCN Circular 21388
Subject
GRB 170728B: Swift/UVOT Upper Limits
Date
2017-07-30T01:46:56Z (8 years ago)
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).
GCN Circular 21387
Subject
GRB 170728B iTelescope observation
Date
2017-07-29T23:19:08Z (8 years ago)
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.
GCN Circular 21384
Subject
GRB 170728B, Swift-BAT refined analysis
Date
2017-07-29T19:04:42Z (8 years ago)
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/
GCN Circular 21383
Subject
GRB 170728B: Fermi GBM detection
Date
2017-07-29T15:47:09Z (8 years ago)
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."
GCN Circular 21381
Subject
GRB 170728B: I-band detection from 1.5m OSN
Date
2017-07-29T14:31:54Z (8 years ago)
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 D���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.
GCN Circular 21380
Subject
GRB 170728B: Fermi-LAT detection
Date
2017-07-29T13:03:36Z (8 years ago)
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.
GCN Circular 21377
Subject
GRB 170728B: Enhanced Swift-XRT position
Date
2017-07-29T05:33:24Z (8 years ago)
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.
GCN Circular 21376
Subject
GRB 170728B: Swift-XRT refined Analysis
Date
2017-07-29T05:05:26Z (8 years ago)
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.
GCN Circular 21375
Subject
GRB 170728B: LT afterglow confirmation
Date
2017-07-29T04:50:11Z (8 years ago)
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.
GCN Circular 21374
Subject
GRB 170728B: NOT optical afterglow confirmation
Date
2017-07-29T02:14:13Z (8 years ago)
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 ��� 9600 ��, 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.
GCN Circular 21373
Subject
GRB 170728B: position of the TNG optical counterpart
Date
2017-07-29T01:49:24Z (8 years ago)
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
(D���Avanzo et al. GCN Circ. 21372).
The source position is:
RA (J2000): 15:51:55.47
Dec (J2000): +70:07:21.1
+/- 0.3���.
We apologize for the delay in sending this information.
GCN Circular 21372
Subject
GRB 170728B: TNG optical afterglow candidate
Date
2017-07-29T01:16:51Z (8 years ago)
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).
GCN Circular 21371
Subject
GRB 170728B: Swift detection of a short burst
Date
2017-07-28T23:24:58Z (8 years ago)
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.)