TITLE: GCN CIRCULAR NUMBER: 6554 SUBJECT: GRB070616: Optical Observation by MITSuME Akeno DATE: 07/06/18 06:36:35 GMT FROM: Nobuyuki Kawai at Tokyo Tech T. Ishimura, Y. Yatsu, T. Shimokawabe, N. Vasquez, Y.kudo, and N. Kawai (TokyoTech) report on behalf of the MITSuME collaboration: We observed the error box of GRB070616 (Starling et al. GCN 6542) with the 3-color 50cm MITSuME Telescope at Akeno, Japan starting at 16:52:26 June 16 UT, 22m53s after the trigger under a poor sky condition with clouds and a high airmass. In the co-added images of Ic, Rc, and g' bands, we did not detect any afterglow candidate in the XRT error circle. The 3-sigma limiting magnitudes based on USNO-B1.0 (I-band) and NOMAD (R-band,g'-band) stars are following. Filter start time end time Exposure Mag (3-sigma upper limit) ----------------------------------------------------------------- g' 16:52:26 18:03:39 58 x 60 s 17.8 Rc 16:52:26 18:03:39 58 x 60 s 19.1 Ic 16:52:26 18:03:39 58 x 60 s 18.6 -----------------------------------------------------------------