[vsnet-grb-info 27061] GRB 201223A: MITSuME Akeno optical observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29164
SUBJECT: GRB 201223A: MITSuME Akeno optical observation
DATE:    20/12/24 02:08:01 GMT
FROM:    Ryohei Hosokawa at Tokyo Institute of Technology  <hosokawa at hp.phys.titech.ac.jp>

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

We observed the field of GRB 201223A (J.D. Gropp et al., GCN #29158,
J. Wood et al., GCN #29161) 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 at 2020-12-23 17:59:18 UT (52s after Swift BAT
trigger). We detected the point source at the position consistent with
the afterglow detected previously (Lipunov et al. GCN #29157, Gropp et
al., GCN #29158, Z.P. Zhu
et al. GCN #29159, Y.-D. Hu et al. GCN #29160).
We measured the magnitudes as follows.

T0+[sec] MID-UT T-EXP[sec] measured magnitudes
------------------------------------------------------------------------------------------------
52 17:59:48 60 g'=15.45+/-0.05, Rc=15.04+/-0.03, Ic=14.77+/-0.04
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time

We used PS1 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.,
https://doi.org/10.1093/pasj/psaa091,
https://arxiv.org/abs/2008.11486; https://github.com/MNiwano/Eclaire).