[vsnet-grb-info 25329] GRB 200324A:MITSuME Akeno optical upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27429
SUBJECT: GRB 200324A:MITSuME Akeno optical upper limits
DATE:    20/03/24 17:45:42 GMT
FROM:    Ryohei Hosokawa at Tokyo Institute of Technology  <hosokawa at hp.phys.titech.ac.jp>

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

We searched for the optical counterpart of GRB 200324A (S. Dichiara et
al., GCN Circular #27428) 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 16:42:46 UT. We did not find any new point
sources within the Swift XRT circle (S. Dichiara et al., GCN Circular
#27428) in all three bands.
We obtained the 5-sigma limits as follows.
T0+[sec] MID-UT T-EXP[sec] 5-sigma limits
------------------------------------------------------------------------------------------------
219 16:46:39 420 g'>18.9,Rc>18.6,Ic>17.6
------------------------------------------------------------------------------------------------
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;
https://github.com/MNiwano/Eclair)