TITLE: GCN CIRCULAR NUMBER: 14023 SUBJECT: GRB 121128A: MITSuME Akeno Optical upper limits DATE: 12/11/30 09:17:45 GMT FROM: Yoichi Yatsu at Tokyo Tech. T. Yoshii, R. Usui, Y.Aoki, S. Kurita, M. Hayashi, Y. Saito, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We observed GRB 121128A ( Oates et al., GCN Circular #14007) 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 was started on 2012-11-28 08:49:50 UT ( ~13453 sec after the burst). We detected the previously reported afterglow ( Oates et al., GCN Circular #14007) in Ic band. The results of photometry (3sigma upper limits) are listed below. The photon flux were calibrated against GSC2.3 catalog. T0+[sec] MID-UT T-EXP[sec] g' Rc Ic ------------------------------------------------------------------------------------------- 14491 09:07:08 1800 > 19.4 > 19.1 17.92+/-0.14 ------------------------------------------------------------------------------------------- T0+ : Elapsed time after the burst [sec] T-EXP: Total Exposure time [sec]