TITLE: GCN CIRCULAR NUMBER: 16036 SUBJECT: GRB 140320C: Mondy optical observations and afterglow confirmation DATE: 14/03/25 12:03:24 GMT FROM: Alexei Pozanenko at IKI, Moscow A.Volnova (IKI), E. Klunko (ISTP), I. Korobtsev (ISTP), M. Eselevich (ISTP), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of GRB 140320C (Mereghetti et al., GCN 16007) with AZT-33IK telescope of Mondy observatory starting on Mar. 20 (UT) 15:12:44 and Mar. 23 (UT) 15:37:46. Several images of 120 s exposure in R-filter ere obtained in both epochs. After receiving all data sets we refined our measurements of the optical source N3 reported early as one of a possible afterglow candidate (Volnova et al., GCN 16012). Enhanced position of the source is (J2000) 08 57 34.40 +71 11 54.7 (uncertainty of 0.35" is each coordinate) is within XRT error circle and apart 1.1" of the center of XRT localization (Pagani et al., GCN 16017). A photometry of the source: date UT start t-T0 Exp. Filter OT err (mid, days) (s) 2014-03-20 15:12:44 0.08918 1560 R 22.63 0.24 2014-03-20 15:38:46 0.12147 3840 R 23.14 0.28 2014-03-23 15:37:46 3.13782 6960 R 23.5 (3 sigma upper limit) is based on two USNO-B1.0 stars (R2 mags) N Id RA Dec. R 1 1612-0081687 08:57:32.78 +71:12:43.9 18.9 3 1611-0081293 08:57:55.56 +71:10:05.6 18.8 Based on our photometry we confirm the source N3 (Volnova et al., GCN 16012) is the afterglow of GRB 140320C. Finding chart can be found at http://grb.rssi.ru/GRB140320C/140320C_AZT33IK_fc.png