TITLE: GCN CIRCULAR NUMBER: 12923 SUBJECT: GRB 120211A: MITSuME Okayama Ks-band upper limit DATE: 12/02/11 16:11:45 GMT FROM: Kenshi Yanagisawa at OAO/NAOJ Kenshi Yanagisawa, Daisuke Kuroda, Yasuhiro Shimizu, Kiichi Okita (OAO/NAOJ), Michitoshi Yoshida (Hiroshima-U), Kouji Ohta(Kyoto-U), and Nobuyuki Kawai(Tokyo Tech.) report on behalf of the MITSuME collaboration: We observed the field of GRB120211A (Sonbas et al., GCNC 12920) in Ks-band with a wide-field NIR camera at Okayama Astrophysical Observatory (Japan). The camera has an effective aperture of 0.91m. Observations started from 12:08 UT on 11th Feburuary, 10.1 min after the BAT trigger, to 13:22 UT. The total exposure of 60 min was successfully obtained. In our co-add image, we did not find any new point source within the enhanced XRT error circle (Goad et al., GCNC 12922) down to limiting magnitude of Ks= 15.5(Vega, S/N=3). The photometric calibration was made against 2MASS field stars. T0+[min] MID-UT T-EXP[min] Ks --------------------------------------------------- +47.1 12:45 60.0 >15.5 (S/N=3) --------------------------------------------------- T0+ : Elapsed time after the burst [sec] T-EXP: Total Exposure time [sec]