TITLE: GCN CIRCULAR NUMBER: 30932 SUBJECT: Swift Trigger 1078701: Mondy, CrAO, AbAO observations, possible optical counterpart DATE: 21/10/11 22:37:38 GMT 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.