TITLE: GCN CIRCULAR NUMBER: 18447 SUBJECT: GRB 151022A: MITSuME Okayama upper limits DATE: 15/10/23 00:53:18 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 151022A (D'Avanzo et al., GCNC 18436) 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 2015-10-22 14:08:12 UT (~100 sec after the burst). We did not find any new point source within the enhanced XRT circle (Beardmore et al., GCNC 18444) in all the three bands. Three sigma upper limits of the OT are listed below. We used SDSS-DR8 catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' Rc Ic ----------------------------------------------------- 0.00471 14:13:19 540.0 >19.0 >19.0 >18.3 0.04291 15:08:20 6240.0 >20.1 >19.9 >19.1 ----------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec]