TITLE: GCN CIRCULAR NUMBER: 11212 SUBJECT: GRB10901A: Murikabushi telescope observation at 3 days after the burst DATE: 10/09/05 13:46:08 GMT FROM: Daisuke Kuroda at OAO/NAOJ D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe(IAO, NAOJ), K. Yanagisawa (OAO, 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 100901A (Immler et al., GCN 11159) with the optical three color (g', Rc and Ic) CCD camera attached to the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory. The observation started on 2010-09-04 17:11:19 UT (~3.15 day after the burst). We detected the previously reported afterglow (Immler et al., GCN 11159; Guidorzi et al., GCN 11160; Kuroda et al., GCN 11205) in g' and Rc bands. Photometric results and three sigma upper limit of the OT are listed below. We used SDSS catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' g'_err Rc Rc_err Ic ---------------------------------------------------------------------- 3.15442 17:16:32 540.0 21.1 0.2 20.6 0.2 >20.1 ---------------------------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec]