[vsnet-grb-info 26115] GRB 200806A: MITSuME Akeno optical upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  28215
SUBJECT: GRB 200806A: MITSuME Akeno optical upper limits
DATE:    20/08/07 05:56:59 GMT
FROM:    Katsuhiro L. Murata at Nagoya U  <murata at u.phys.nagoya-u.ac.jp>

K. L. Murata, R. Adachi, R. Hosokawa, 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 200806A (Ambrosi et al., GCN 28211; Beardmore
et al., GCN 28214) 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 2020-08−06
15:30:34 UT. The first 15 images were heavily affected by the presence of
the moon. We stacked the images excluding the 15 images and did not find
any new point sources within the enhanced Swift/XRT error circle (Beardmore
et al., GCN 28214) of the stacked images. We obtained the 5-sigma limits as
follows.

T0+[min] MID-UT T-EXP[sec] 5-sigma limits
------------------------------------------------------------------------------------------------
19 2020-08-06T15:57:10 960 g'>16.7, Rc>16.7, Ic>16.9
------------------------------------------------------------------------------------------------
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)