[vsnet-grb-info 26169] GRB 200819A: MITSuME Akeno optical upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  28269
SUBJECT: GRB 200819A: MITSuME Akeno optical upper limits
DATE:    20/08/19 23:59:46 GMT
FROM:    Katsuhiro L. Murata at Nagoya U  <murata at u.phys.nagoya-u.ac.jp>

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

We observed the field of GRB 200819A (Dichiara et al., GCN 28263;
Evans et al., GCN 28265) 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 with a series of 60 sec exposures started on
2020-08−19 15:45:44 UT. Some images were heavily affected by bad
weather conditions. We stacked the images with good weather
conditions. We did not find any new point sources within the enhanced
Swift/XRT error circle (Evans et al., GCN 28265) of the stacked
images. We obtained the 5-sigma limits as follows.

T0+[sec] MID-UT T-EXP[sec] 5-sigma limits
------------------------------------------------------------------------------------------------
~290 2020-08-19T17:36:48 5640 g’>18.4, Rc>19.0, Ic>19.3
------------------------------------------------------------------------------------------------
T0+: Elapsed time after the burst
T-EXP: Total Exposure time

We used the 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., submitted;
https://github.com/MNiwano/Eclaire)