GCN Circular 30932
Subject
Swift Trigger 1078701: Mondy, CrAO, AbAO observations, possible optical counterpart
Date
2021-10-11T22:37:38Z (3 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
N. Pankov (HSE), A. Pozanenko (IKI), S. Belkin (IKI), E. Klunko (ISTP),
V. Rumyantsev (CrAO), R. Ya. Inasaridze (AbAO) report on behalf of GRB
IKI FuN:
We observed the field of Swift/BAT trigger 1078701 (Bernardini et al.,
GCN 30929) with AZT-33IK telescope of Sayan observatory (Mondy), ZTSh
telescope of CrAO, and AS-32 telescope of Abastumani observatory. The
error circle of BAT localization was fully covered in all our
observations. In the first epoch of observations started on Oct. 10
(UT) 11:32:39 (about 50 minutes after trigger) within BAT localization
circle (Bernardini et al., GCN 30929) we identified only one objects
which is absent in PS1 catalogue. The coordinates of the object are
(J2000) 19:08:08.59 29:50:12.7 with uncertainty of 0.3 arcsec in both
coordinates. The brightness of the object in R-filter in a stacked
image is R=21.13 +/- 0.19. The object is not present in following epochs
of our observations. Preliminary photometry of the object and upper
limits in stacked images are following
Date UT start t-T0 Filter Exp. OT Err. UL(3s) telescope
(mid, days) (s)
2021-10-10 11:32:39 0.05560 R 30*120 21.13 0.19 21.9 AZT-33IK
2021-10-10 15:42:40 0.20819 R 47*60 n/d n/d 20.5 AS-32
2021-10-10 16:24:24 0.23736 R 12*120 n/d n/d 23.8 ZTSh
2021-10-11 17:26:38 1.28057 R 15*120 n/d n/d 23.6 ZTSh
The photometry is based on the nearby USNO-B1.0 stars
USNO-B1.0 R2
1198-0327115 18.06
1198-0327174 17.81
The power law index of light curve of the object between the detection
epoch and deep non-detection is less than -1.7 and do not contradict the
typical light curve of GRBs. We could suggest the object as a
counterpart of of GRB which might have been registered by Swift as the
trigger 1078701.