[vsnet-grb-info 26171] GRB 200819A: MITSuME Ishigaki optical upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  28271
SUBJECT: GRB 200819A: MITSuME Ishigaki optical upper limits
DATE:    20/08/20 04:43:13 GMT
FROM:    Katsuhiro L. Murata at Nagoya U  <murata at u.phys.nagoya-u.ac.jp>

Takashi Horiuchi, Hidekazu Hanayama (NAOJ), Katsuhiro L. Murata,
Yoichi Yatsu, Nobuyuki Kawai (Tokyo Tech) 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 105 cm Murikabushi telescope of
Ishigakijima Astronomical Observatory, Okinawa, Japan.

The observation with a series of 60 sec exposures started on
2020-08−19 16:35:33 UT. Throughout, the images were terribly extended
by the altitude oscillation of the Murikabushi Telescope. We stacked
the 79 images and did not find any new point sources other than the
USNO-B1.0 sources from the stacked images. We obtained the SN = 10
limits as follows.

T0+[min] MID-UT T-EXP[sec] SN=10 limits
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52 2020-08-19T17:21:38 960 g'>18.7, Rc>19.0, Ic>17.8
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