[vsnet-grb-info 21679] GRB190123A: MITSuME Akeno optical upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23778
SUBJECT: GRB190123A: MITSuME Akeno optical upper limits
DATE:    19/01/24 10:11:22 GMT
FROM:    Kazuki Shiraishi at Tokyo Institute of Technology  <shiraishi at hp.phys.titech.ac.jp>

K. Shiraishi, K. L. Murata, R. Itoh, Y. Tachibana, S. Harita,

K. Morita, K. Iida, M. Niwano, R. Adachi, M. Oeda,  Y. Yatsu,

and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration



We searched for the optical counterpart of

GRB 190123A (A. D'Ai et al., GCN #23769)

with the optical three color (g', Rc, and Ic)

CCD cameras attached to the MITSuME 50 cm telescope at Akeno

Observatory,Yamanashi, Japan.



The observation started on 12:20:56 UT which corresponds to 103 sec

after the trigger.

We did not find any new point source within the enhanced XRT circle

D’Ai et al., GCN #23769;  A.P. Beardmore et al., GCN #23771) in all three bands.

We obtained following 5 sigma limits for the magnitudes.



T0+[sec]    MID-UT      T-EXP[sec]    g'       Rc        Ic

-------------------------------------------------------------------------------------------------------

103  12:25:31    540    >18.2     >17.8     >17.0

723  12:35:51    540    >17.9     >17.7     >17.6

1,764  14:21:35    10,800    >18.4     >18.2     >17.4

-------------------------------------------------------------------------------------------------------

T0+ : Elapsed time after the burst

T-EXP: Total Exposure time

We used UCAC-4 catalog for flux calibration.