[vsnet-grb-info 21612] GRB190109B: MITSuME Akeno optical upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23711
SUBJECT: GRB190109B: MITSuME Akeno optical upper limits
DATE:    19/01/15 11:15:43 GMT
FROM:    Motoki Oeda at Tokyo Inst. of Tech.  <oeda at hp.phys.titech.ac.jp>

M. Oeda,  K. L. Murata, R. Itoh, Y. Tachibana, S. Harita, K. Morita,
K.Shiraishi, K. Iida, M. Niwano, R. Adachi, Y. Yatsu, and N. Kawai
(TokyoTech)
report on behalf of the MITSuME collaboration:

We searched for the optical counterpart of GRB 190109B (B. Sbarufatti
et al.,GCN Circular #23648) 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 11:57:03.81 UT. We did not find any new
point source within the enhanced XRT circle (A.P. Beardmore et al.,
GCN Circular #23652) in all three bands. We obtained following 5 sigma
limits for the magnitudes.

T0+[min]    MID-UT      T-EXP[sec]    g'       Rc        Ic
-------------------------------------------------------------------------------------------------------
0.913      11:57:33.81           60        >17.54     >17.26     >16.72
0.913       12:31:59.3          3660      >19.29     >17.67     >17.12
-------------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used UCAC-4 catalog for flux calibration.