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GCN Circular 27236

GRB 200227A: MITSuME Akeno optical upper limit
2020-02-27T11:59:48Z (4 years ago)
Motoki Oeda at Tokyo Inst. of Tech. <>
M. Oeda, R. Adachi, K. L. Murata, K. Shiraishi, K. Iida, M. Niwano, F.
Ogawa, S. Toma, R. Hosokawa, N. Nakamura, Y. Yatsu, and N.
Kawai(TokyoTech) report on behalf of the MITSuME collaboration:

We searched for the optical counterpart of GRB 200227A (Fermi GBM Team
et al.,GCN Circular #27233, S. Laha et al., GCN Circular #27234) 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 09:05:08 UT. We did not find any new point
sources within the Swift/XRT circle (S. Laha et al., GCN Circular
#27234) in all three bands.
We obtained the 5-sigma limits as follows.

T0+[hour] MID-UT T-EXP[sec] 5-sigma limits
2.2   09:41:13  900  g���>18.4,Rc>18.2,Ic>17.5
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time

We used UCAC4 catalog for flux calibration.
The magnitudes are expressed in the AB system.
The images were processed in real-time through the MITSuME GPU
reduction pipeline (Niwano et al. ,in prep;
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