TITLE: GCN CIRCULAR NUMBER: 12768 SUBJECT: GRB111228A: MITSuME Akeno photometry of the optical afterglow DATE: 11/12/29 15:34:59 GMT FROM: Yoichi Yatsu at Tokyo Tech. R. Usui, Y. Aoki, S. Song, M. Hayashi, K. Kawakami, K. Tokoyoda, Y. Saito, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB 111228A (Ukwatta et al., GCNC 12737) with the optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Akeno Observatory, Yamanashi, Japan. The observation started on 2011-12-28 15:45:47 UT (~ 64 sec after the burst). We detected the previously reported afterglow (Ukwatta, GCNC 12737; Xin et al., GCNC 12738) in all the three bands. Photometric results and are listed below. We used GSC2.3 catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' g'_err Rc Rc_err Ic Ic_err ---------------------------------------------------------------------- 0.00074 15:46:02 30.0 17.3 0.2 16.12 0.09 15.5 0.1 ---------------------------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec]