GCN Circular 12438
Subject
GRB 110921A: optical observations
Event
Date
2011-10-16T01:25:38Z (14 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Volnova (SAI MSU), A. Pozanenko (IKI), E. Klunko (ISTP), V. Rumyantsev
(CrAO), N.Pit (CrAO) on behalf of larger GRB follow up collaboration
report:
We observed the field of the Swift GRB 110921A (Baumgartner et al., GCN
12373) with AZT-33IK telescope of Sayan observatory (Mondy) on Sep. 21
between (UT) 14:36:31 -- 16:05:00 and AZT-11 telescope of CrAO on Sep. 21
between (UT) 17:38:46 -- 19:00:15. In a combined image of a few first frames
taken with AZT-33IK we detected a faint source which coincides with the
optical counterpart of GRB 110921A (Xin et al., GCN 12377; Xu et al., GCN
12385). A photometry is based on the star USNO B1.0 1263-0338839 (19 36
21.52 +36 19 56.2) assuming R=16.13
T0+, Filter, Exposure, OT, UL(3 sigma), Telescope
(mid, d) (s)
0.03934 R 850 22.08 +/- 0.18 22.3 AZT-33IK
0.07558 R 1920 n/d 22.5 AZT-33IK
0.18620 R 4860 n/d 21.3 AZT-11
In a combined image of a total exposure of 3030 s taken with AZT-33IK
telescope we clearly detected the SDSS object noted by Xu et al. (GCN 12385)
and Vreeswijk et al. (GCN 12387). The photometry of the SDSS object against
the above calibration star is R=22.8 +/- 0.3.