TITLE: GCN CIRCULAR NUMBER: 7087 SUBJECT: GRB 071112C MITSuME Akeno early optical observation DATE: 07/11/14 06:44:18 GMT FROM: Nobuyuki Kawai at Tokyo Tech T. Ishimura, T. Shimokawabe, Y. Mori, Y. Kudou, N. Vasquez, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB 071112C (Perri et al., GCN 7059) with the 3-color 50cm MITSuME Telescope at Akeno, Japan starting at 18:34:39 UT, 102s after the trigger. In the images of g' and Rc bands, we detected the optical counterpart reported by several authors (GCNs 7059, 7061, 7062 etc.). Photometric calibration was done using the USNO-B1.0 (Ic-band) and NOMAD (g'-bands) catalogs. The results are following: start time end time Exposure g' [mag] Rc[mag] --------------------------------------------------------------- 18:34:39 18:35:39 1 x 60s 17.6 +/- 0.5 17.3 +/- 0.3 ---------------------------------------------------------------