TITLE: GCN CIRCULAR NUMBER: 19475 SUBJECT: GRB 160525B: MITSuME Akeno optical upper limits DATE: 16/05/31 10:05:57 GMT FROM: Taketoshi Yoshii at Tokyo Tech K. Saisho, Y. Muraki, Y. Ono, T. Fujiwara, T. Yoshii, Y. Saito, Y. Tachibana, H. Ohuchi, Y. Yano, S. Harita, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We searched for the optical counterpart of GRB 160525B (H. A. Krimm et al., GCN Circular #19459) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan. The observation started on 2016-05-25 10:03:51 UT (~0.65 h after the burst). We did not find any new point source within XRT circle in all three bands. We obtained following limits for the magnitudes. T0+[hour] MID-UT T-EXP[sec] g' Rc Ic ---------------------------------------------------------------------------- 0.65 15:58:53 1140 >18.6 >18.2 >17.6 ---------------------------------------------------------------------------- T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used GSC2.3 catalog for flux calibration.