TITLE: GCN CIRCULAR NUMBER: 19201 SUBJECT: GRB 160313A: Mondy optical upper limit DATE: 16/03/16 20:22:15 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), A. Volnova (IKI), E. Klunko (ISTP), I. Korobtsev (ISTP), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of the GRB 160313A (D'Ai et al., GCN 19171) with AZT-33IK telescope of Sayan observatory (Mondy) starting on March, 13 (UT) 16:39:40. We do not detect any source within enhanced Swift-XRT position (Goad et al., GCN 19174). Preliminary photometry of the combined image is following Date UT start t-T0 Filter Exp. UpperLimit (3 sigma) (mid, days) (s) 2016-03-13 16:39:40 0.60586 R 30*120 23.6 Photometry is based on nearby SDSS-DR9 stars, Lupton transformations into R. The nearest source to the enhanced XRT position is 5.5 arcsec East, in coordinates (J2000) 12:15:11.86 +57:17:00.0 with uncertainty of 0.5 arcsec in both coordinates. The source magnitude is R=23.3+/-0.2. The source is not presented in SDSS-DR9 but barely visible in SDSS r-image.