TITLE: GCN CIRCULAR NUMBER: 17204 SUBJECT: GRB 141220A: MITSuME Okayama upper limits DATE: 14/12/20 23:57:05 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 MITSuME and OISTER collaboration: We observed the field of GRB 141220A (Cummings et al., GCNC 17196) 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 2014-12-20 16:27:31 UT (~10.4 h after the burst) We could not detect the previously reported afterglow (Cummings et al., GCNC 17196; Gorosabel et al., GCNC 17197; de Ugarte Postigo et al., GCNC 17198) in all the three bands. Three sigma upper limits of the OT are listed below. We used SDSS-DR7 catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' Rc Ic ----------------------------------------------------- 0.47547 17:27:32 5940.0 >19.8 >19.9 >19.0 ----------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec]