TITLE: GCN CIRCULAR NUMBER: 8724 SUBJECT: GRB 081222: MITSuME optical observation DATE: 08/12/25 01:51:58 GMT FROM: Michitoshi Yoshida at Okayama Astrophysical Obs D. Kuroda, M. Yoshida, K. Yanagisawa, Y. Shimizu, S. Nagayama, H. Toda (OAO, NAOJ) and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB 081222 (Grupe et al. GCN 8691) with the optical three color (g', Rc and Ic) imager attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory on Dec.22 2008 UT. We detected a fading point source at the position of the X-ray - optical afterglow candidate (Covino et al. GCN 8692; Updike et al. GCN8693; Grupe GCN 8705) in Rc band. Photometric results are listed below. We used GSC2.3 catalog for flux calibration. # Mid-MJD Mid-UT EXP-T g' Rc Ic ------------------------------------------------------------- 54822.401100 09:37:36 540.0 >18.3 18.0+/-0.3 >17.8 54822.438455 10:31:23 2940.0 >19.2 18.9+/-0.3 >18.2 54822.469650 11:16:18 4500.0 >19.2 19.3+/-0.4 18.6+/-0.3 -------------------------------------------------------------