GCN Circular 27576

F. Ogawa, R. Adachi, R. Hosokawa, K. L. Murata, M. Niwano, N.
Nakamura, Y. Yatsu, and N. Kawai(TokyoTech) report on behalf of the
MITSuME collaboration:

We searched for the optical counterpart of GRB 200412B (The Fermi GBM
team, GCN Circular #27547) 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 2020-04-13 15:27:09 UT. We detected the
point source at the position consistent with the afterglow detected
previously (E. Gorbovskoy et al. GCN #27555).
We measured the magnitudes as follows.
T0+[hour] MID-UT T-EXP[sec] measured magnitudes
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30.2 2020-04-13 17:19:02 10800 g'=20.1+/-0.2,Rc=19.6+/-0.2,Ic=19.5+/-0.2
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T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
The magnitudes are expressed in the Vega system.