TITLE: GCN CIRCULAR NUMBER: 13897 SUBJECT: GRB 121024A: MITSuME Ishigakijima upper limits DATE: 12/10/25 12:20:18 GMT FROM: Daisuke Kuroda at OAO/NAOJ D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ), K. Yanagisawa (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 121024A (Pagani et al., GCNC 13886) 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 2012-10-24 14:30:52 UT (~11.6 h after the burst) We did not find any new point source within the enhanced XRT circle (Osborne et al., GCNC 13894) in all the three bands. We also could not detect the previously reported afterglow (Klotz et al., GCNC 13887). 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 ------------------------------------------------------ 0.52401 15:30:47 6060.0 >21.7 >21.4 >20.6 ------------------------------------------------------ T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec]