TITLE: GCN CIRCULAR NUMBER: 7341 SUBJECT: GRB080229: Possible optical afterglow DATE: 08/03/01 03:16:54 GMT FROM: Michitoshi Yoshida at Okayama Astrophysical Obs 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 performed optical imaging observations (g', Rc, and Ic) of the field of GRB 080229 (Cannizzo et al. GCN 7335) with 50cm MITSuME telescope at Okayama Astrophysical Observatory from UT 17:06:55 (117sec after the trigger) to UT 17:24:40 on Feb 29 2008. We found a faint fading source in the XRT error circle (Cannizzo et al: GCN 7335) only in the Ic band. There was no source in the g' and the Rc bands. Together with the UVOT results (Kuin and Cannizzo GCN7339), this may suggest that this GRB is a high- redshift one. Follow-up observations in infrared bands are encouraged. The magnitude of the fading source and 3-sigma upper limits are summarized below. Observation date 2008-02-29 UT mid-UT exp-T g' Rc Ic --------------------------------------------- 17:09:40 5 min >17.5 >17.8 17.1+-0.3 17:18:58 11 min >17.6 >18.2 >18.0 --------------------------------------------- The values quoted above are not corrected for the Galactic extinction.