TITLE: GCN CIRCULAR NUMBER: 6050 SUBJECT: GRB 070125: MITSuME Okayama optical observation DATE: 07/01/29 03:34:14 GMT FROM: Michitoshi Yoshida at Okayama Astrophysical Obs M. Yoshida, K. Yanagisawa, (OAO, NAOJ) and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We detected the optical afterglow candidate of GRB 070125 reported by by Cenko and Fox (GCN 6028) with the 50cm MITSuME Telescope at Okayama Astrophysical Observatory on January 26 UT. Photometric calibration was done using USNO-B1.0 catalog magnitudes of eight stars around the target. The results are following. UT 26 January 2007 12:25 - 17:23 mid-UT 14:53 total exp time 123 min. (1 min. exp. x 123 frames) ------------------------------ g' 19.6 mag. +/- 0.2 mag. Rc 18.8 mag. +/- 0.2 mag. Ic 18.0 mag. +/- 0.3 mag. ------------------------------ Time variability in Rc UT mid-UT exp.time Rc mag. ----------------------------------------------- 12:25 - 13:06 12:45 30 min. 18.9 +/- 0.3 13:07 - 14:35 13:51 37 min. 19.0 +/- 0.3 16:01 - 16:44 16:22 30 min. 18.7 +/- 0.2 16:44 - 17:23 17:03 26 min. 19.4 +/- 0.4 -------------------------------------------------   吉田道利 国立天文台 岡山天体物理観測所 所長 Michitoshi Yoshida, Dr. Director of Okayama Astrophysical Observatory, National Astronomical Observatory of Japan Phone:+81-865-44-2155 FAX:+81-865-44-2360 yoshida@oao.nao.ac.jp -------------------------------------------------