[vsnet-grb-info 12442] GRB 120923A: MITSuME Okayama Optical upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  13817
SUBJECT: GRB 120923A: MITSuME Okayama Optical upper limits
DATE:    12/09/25 05:54:47 GMT
FROM:    Daisuke Kuroda at OAO/NAOJ  <dikuroda at oao.nao.ac.jp>

D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ),
S. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto)
and N. Kawai(Tokyo Tech)
report on behalf of the MITSuME collaboration:

We observed the field of GRB 120923A (Yershov et al., GCNC 13796)
with the optical three color (g', Rc and Ic) CCD camera attached
to the MITSuME 50cm telescope of Okayama Astrophysical Observatory.

The observation started on 2012-09-23 10:00:39 UT (~4.7 h after the burst)
We did not find any new point source within the enhanced XRT circle
(Goad et al., GCNC 13801) in all the three bands.
We also could not detect the previously reported afterglow (Levan et al.,
GCNC 13802).

Three sigma upper limits of the OT are listed below. We used
SDSS catalog for flux calibration.

T0+[day]   MID-UT   T-EXP[sec]    g'     Rc     Ic
------------------------------------------------------
0.23958    11:01:05    6360.0   >20.6  >20.2  >18.9
------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]