GCN Circular 18841

T.Fujiwara, Y.Saito, T. Yoshii, Y. Yano, Y. Tachibana,
Y.Ono, S.Harita, Y.Muraki, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:

We searched for the optical counterpart of GRB 160104A (A. Melandri et al., GCN
Circular #18815) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm
telescope of Akeno Observatory, Yamanashi, Japan.

The observation started on 2016-01-04 11:24:56 UT (46 sec after the burst) and
we detected the optical counterpart in Rc and Ic band.
The measured magnitudes were listed as follows.

We obtained following results for the magnitudes.

T0+[sec]    MID-UT      T-EXP[sec]         g'              Rc                      Ic
-------------------------------------------------------------------------------------------------------
382            11:38:50        900                  > 20.6         18.9 +/- 0.1      18.3 +/- 0.2
13473         16:03:30        5880                 > 21.3         20.2 +/- 0.2      19.5 +/- 0.3
-------------------------------------------------------------------------------------------------------

T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.