TITLE: GCN CIRCULAR NUMBER: 17098 SUBJECT: GRB 141121A: MITSuME Ishigakijima Optical Observation after 3 days DATE: 14/11/25 01:46:25 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 and OISTER collaboration: We observed the field of GRB 141121A (Lien et al., GCNC 17075) 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 2014-11-24 17:17:04 UT (~3.6 days after the burst). We detected the previously reported afterglow (Tanga et al., GCNC 17078; Perley et al., GCNC 17081; Kuroda et al., GCNC 17091) in all the three bands. Photometric results of the OT are listed below. We used SDSS-DR7 catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' g'_err Rc Rc_err Ic Ic_err -------------------------------------------------------------------------- 3.60810 18:26:22 5100.0 21.39 0.13 20.37 0.08 19.90 0.12 -------------------------------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec]