TITLE: GCN CIRCULAR NUMBER: 14108 SUBJECT: GRB 121226A: MITSuME Okayama Optical upper limits DATE: 12/12/26 23:55:05 GMT FROM: Daisuke Kuroda at OAO/NAOJ D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ), S. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB 121226A (Krimm et al., GCNC 14105) with the optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory. The observation started on 2012-12-26 19:11:59 UT (~2.3 min after the burst). We did not find any new point source within the XRT circle (Krimm et al., GCNC 14105) in all the three bands. Three sigma upper limits of the OT are listed below. We used GSC2.3 catalog for flux calibration. T0+[day] MID-UT T-EXP[sec] g' Rc Ic ------------------------------------------------------ 0.04333 20:12:06 6360.0 >20.2 >20.2 >19.5 ------------------------------------------------------ T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec]