[vsnet-grb-info 17199] GRB 151031A: MITSuME Akeno optical upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18551
SUBJECT: GRB 151031A: MITSuME Akeno optical upper limits 
DATE:    15/11/02 10:02:14 GMT
FROM:    Taketoshi Yoshii at Tokyo Tech  <yoshii.t.ac at m.titech.ac.jp>

T.Fujiwara, T. Yoshii, Y. Saito, Y. Tachibana, Y. Yano, 
Y.Ono, S.Harita, Y.Muraki, Y. Yatsu, and N. Kawai (Tokyo Tech)

report on behalf of the MITSuME collaboration:

We searched for the optical counterpart of GRB 151031A (E. Sonbas et al., GCN Circular #18538) 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 2015-10-31 16:18:19 UT (10.5 h after the burst).
We did not find any new point source within XRT circle in all three bands.

We obtained following limits for the magnitudes.

T0+[sec] MID-UT T-EXP[sec] g' Rc Ic
----------------------------------------------------------
37669  17:00:37  4440  > 18.8  > 18.9  > 18.3
----------------------------------------------------------
T0+ : Elapsed time after the burst 
T-EXP: Total Exposure time 
We used GSC2.3 catalog for flux calibration.