[vsnet-grb-info 19732] GRB 170822A: MITSuME Akeno Optical Observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21652
SUBJECT: GRB 170822A: MITSuME Akeno Optical Observation
DATE:    17/08/23 07:15:59 GMT
FROM:    Katsuhiro L. Murata at Nagoya U  <murata at u.phys.nagoya-u.ac.jp>

K. L. Murata, Y. Saito, R. Itoh, Y. Tachibana, T. Yoshii, S. Harita, K.
Morita, T. Ozawa, H. Mamiya, K. Shiraishi, Y. Yatsu, and N. Kawai (Tokyo
Tech)
report on behalf of the MITSuME collaboration:

We searched for the optical counterpart of GRB 170822A (Melandri et al.,
GCN Circular #21640) 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 2017-08-22 16:27:38.15 UT . We did not find any
new point source within enhanced XRT circle (Evans et al., GCN Circular
#21643) in all three bands.
We obtained following limits for the magnitudes.


T0+[hour]    MID-UT      T-EXP[sec]         g'              Rc
       Ic
-------------------------------------------------------------------------------------------------------
~7.21        16:48:33.09      2280          >20.8        >20.1
 >18.9
-------------------------------------------------------------------------------------------------------

T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.