[vsnet-grb-info 13829] GRB 130831A: MITSuME Akeno Optical observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15143
SUBJECT: GRB 130831A: MITSuME Akeno Optical observation
DATE:    13/08/31 15:03:11 GMT
FROM:    Taketoshi Yoshii at Tokyo Tech  <yoshii.t.ac at m.titech.ac.jp>

T. Yoshii, K. Ito, Y. Saito, Y. Yano, R. Usui, Y. Tachibana, 
S. Kurita, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:

We observed the field of GRB 130831A (L. M. Z. Hagen et al., GCNC 15139) with the 
optical three color (g, Rc, and Ic) CCD cameras attached to the MITSuME 50 cm
telescope of Akeno Observatory, Yamanashi, Japan.
And we continue observing .

The observation started on 2013-08-31 13:06:14 UT ( 118 sec after the burst).
And we detected the previously reported afterglow .
But weather condition was not so good.
The measured magnitudes were listed below.

T0+[sec]       MID-UT        T-EXP[sec]              g'                            Rc                          Ic 
------------------------------------------------------------------------------------------------------------------------------
  ~118           13:07:41         300              15.40+/-0.23        15.16+/-0.33            analyzing
------------------------------------------------------------------------------------------------------------------------------
(The photon flux were calibrated against GSC2.3 catalog.)