TITLE: GCN CIRCULAR NUMBER: 13373 SUBJECT: Swift trigger 524642 / SwJ1910.2-0546 DATE: 12/06/21 14:39:45 GMT FROM: Alexei Pozanenko at IKI, Moscow V. Rumyantsev, K. Antonyuk (CrAO), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of Swift trigger 524642 with AZT-11 telescope of CrAO observatory starting on June 18 (UT) 20:23:03 under favorable weather conditions and seeing of about 2.4 arsces. At the edge of the Swift-XRT localization (+19h 10m 22.39s -05d 47' 55.3" GRB_ERROR=5.2") we found bright optical source which is absent on any DSS2 plates. The coordinates of the source (J2000) 19 10 22.78 -05 47 56.4 is 5.9" away from the center of the XRT localization and coincide with UVOT position reported in GCN/SWIFT NOTICE. Photometry of the source is based on the USNO-B1.0 star 0842-0520198 (19 10 23.32 -05 46 52.8) assuming R=14.70: T0+ Filter, Exposure, OT, uplim (3 sigma) (mid, d) (s) 0.0666 R 13x180 16.033 +/- 0.005 21.7 The finding chart can be found at http://grb.rssi.ru/Swift_524642/Swift_524642_20120618_R_AZT11.PNG