[vsnet-grb-info 27303] GRB 210205A: MITSuME Ishigaki optical observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29406
SUBJECT: GRB 210205A: MITSuME Ishigaki optical observation
DATE:    21/02/05 22:01:18 GMT
FROM:    Takashi Horiuchi at Ishigakijima Astronomical Obs  <takashi.horiuchi at nao.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 210205A (Dichiara et al., GCN 29397)
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
2021-02−05 11:22:29 UT (2 min after Swift BAT trigger).
We stacked the 25 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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2 2021-02-05T11:36:37 1500 g' > 18.7, Rc > 19.0, Ic > 17.8
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