TITLE: GCN CIRCULAR NUMBER: 6922 SUBJECT: GRB 071011: MITSuME Optical Observations DATE: 07/10/16 14:41:48 GMT FROM: Nobuyuki Kawai at Tokyo Tech D. Kuroda, K. Yanagisawa, M. Yoshida (NAOJ), T. Ishimura, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB071011 (Marshall et al., GCN 6882) with the 3-color 50cm MITSuME Telescope at Okayama Astrophysical Observatory, and 3-color 105cm Telescope at Ishigakijima Astronomical Observatory. The observations started at 12:50:06 Oct.11 (9m53s after the trigger) at Okayama, and at 13:04:15 Oct.11 (24m02s after the trigger) at Ishigakijima. In the co-added images of Ic and Rc bands (Okayama), and Ic, Rc, and V bands (Ishigakijima), we detected the optical afterglow reported by Cenko et al. (GCN 6895). We estimate the magnitudes relative to the USNO B1.0 catalog. The results are followings. ### Results at Okayama ### start end Exposure Ic mag Rc mag ------------------------------------------------------- 12:50:06 13:00:06 10 x 60 s 18.2 +/- 0.4 19.0 +/- 0.3 13:02:48 13:12:48 10 x 60 s 19.2 +/- 0.4 19.5 +/- 0.4 13:15:26 13:25:26 10 x 60 s 19.3 +/- 0.4 -- ------------------------------------------------------- ### Results at Ishigakijima ### start end Exposure Ic mag Rc mag V mag ----------------------------------------------------------------------- 13:04:15 13:19:14 5 x 60 s 18.6 +/- 0.2 20.1 +/- 0.2 -- 13:25:17 13:58:09 5 x 60 s 19.1 +/- 0.4 19.9 +/- 0.2 -- 13:04:15 13:58:09 10 x 60 s -- -- 21.0 +/- 0.5 ------------------------------------------------------------------------