[vsnet-grb-info 20303] GRB 180204A: MITSuME Okayama optical upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22399
SUBJECT: GRB 180204A: MITSuME Okayama optical upper limits
DATE:    18/02/07 08:04:10 GMT
FROM:    Kotaro Morita at Tokyo Tech  <morita at hp.phys.titech.ac.jp>

 K. Morita, R. Itoh, K. L. Murata, T. Yoshii, Y. Tachibana, S. Harita, 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 180204A (K. L. Page et al.,
GCN Circular #22375) with the optical three color (g', Rc, and Ic) CCD
cameras attached to the MITSuME 50 cm telescope of Okayama Astrophysical
Observatory, Japan.
The observation started on 2018-02-04 9:37:11.83 UT. We did not find any
new point source within the XRT circle (J. P. Osborne et al., GCN Circular
#22377) in all three bands.
We obtained following limits for the magnitudes.

T0+[h]    MID-UT      T-EXP[sec]    g'        Rc        Ic
------------------------------------------------------------
-------------------------------------------
~7.0         9:48:54         1140       >17.5     >17.4      >17.0
------------------------------------------------------------
-------------------------------------------

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