TITLE: GCN CIRCULAR NUMBER: 22517 SUBJECT: GRB 180316A: MITSuME Okayama optical upper limits DATE: 18/03/19 07:23:59 GMT FROM: Katsuhiro L. Murata at Nagoya U K. L. Murata, R. Itoh, T. Yoshii, Y. Tachibana, S. Harita, K. Morita, T. Ozawa, H. Mamiya, K. Shiraishi, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We searched for the optical counterpart of GRB 180316A (A. Melandri et al., GCN Circular #22500) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Okayama Astrophysical Observatory, Japan. The observation started on 16:19:04 UT. We did not find any new point source within enhanced XRT circle (P.A. Evans et al., GCN Circular #22508) in all three bands. We obtained following limits for the magnitudes. T0+[hour] MID-UT T-EXP[sec] g' Rc Ic ------------------------------------------------------------ ------------------------------------------- 12.22 19:44:32 1980 >17.3 >17.4 >17.4 ------------------------------------------------------------ ------------------------------------------- T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used GSC2.3 catalog for flux calibration.