TITLE: GCN CIRCULAR NUMBER: 14498 SUBJECT: GRB 130427A: MITSuME Okayama and Ishigakijima Optical Observation after 1 day DATE: 13/04/29 06:06:15 GMT FROM: Daisuke Kuroda at OAO/NAOJ D. Kuroda, (OAO, NAOJ), H. Hanayama (IAO, NAOJ), K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ), T. Miyaji J. Watanabe, (IAO, 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 130427A (Masell et al., GCNC 14448) with the optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory and the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory. We detected the previously reported afterglow (Elenin et al., GCNC 14450) in all the three bands. Photometric results of the OT are listed below. We used SDSS catalog for flux calibration. Okayama Astrophysical Observatory: The observation started on 2013-04-28 11:29:25 UT (~1.15 days after the burst). #T0+[day] MID-UT T-EXP[sec] g' g'_err Rc Rc_err Ic Ic_err ----------------------------------------------------------------------- 1.16123 11:40:06 1440.0 18.4 0.2 17.9 0.1 17.7 0.1 ------------------------------------------------------------------------ T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec] Ishigakijima Astronomical Observatory: The observation started on 2013-04-28 14:02:08 UT (~1.26 days after the burst). #T0+[day] MID-UT T-EXP[sec] g' g'_err Rc Rc_err Ic Ic_err ----------------------------------------------------------------------- 1.31290 15:18:30 1020.0 18.61 0.06 18.22 0.04 17.37 0.05 ------------------------------------------------------------------------ T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec]