[vsnet-grb-info 23755] GRB 190926A: MITSuME Akeno optical upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  25854
SUBJECT: GRB 190926A: MITSuME Akeno optical upper limits
DATE:    19/09/27 03:33:15 GMT
FROM:    Adachi Ryo at Tokyo Institute of Tech  <adachi at hp.phys.titech.ac.jp>

R. Adachi, K. L. Murata, M. Oeda, K.Shiraishi, K. Iida, M. Niwano,
F. Ogawa, R. Hosokawa, S. Toma, Y. Yatsu, and N. Kawai (TokyoTech)
report on behalf of the MITSuME collaboration:

We searched for the optical counterpart of GRB 190926A (A. Melandri et
al., GCN Circular #25848) 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 16:16:33 UT. We did not find any new point
sources within the XRT circle (M.R. Goad et al., GCN Circular #25850)
in all three bands.
We obtained the following 5-sigma limits for the magnitudes.

T0+[hour]   MID-UT    T-EXP[sec]    5-sigma limits
------------------------------------------------------------------------------------------------
 ~7.0         18:13:34    6960              g'>19.8, Rc>19.5, Ic>19.2
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used UCAC4 catalog for flux calibration.
The magnitudes are expressed in the AB system.