GCN Circular 18174

D. Kuroda (OAO, NAOJ),  H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ),
K. Yanagisawa (OAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima),
K. Ohta (Kyoto) and N. Kawai(Tokyo Tech)
report on behalf of the MITSuME and OISTER collaboration:

We observed the field of GRB 150818A (D'Elia et al., GCNC 18152)
with the optical three color (g', Rc and Ic) CCD camera attached
to the Murikabushi 1m telescope of Ishigakijima Astronomical
Observatory.

The observation started on 2015-08-18 13:09:10 UT (~1.5h after the burst).
We could not detect the previously reported afterglow
(Marshall and D'Elia, GCNC 18155; McCauley et al., GCNC 18161;
Schulze et al., GCNC 18164) in all the three bands.

Three sigma upper limits of the OT are listed below.
We used GSC2.3 catalog for flux calibration.

#T0+[day]  MID-UT    T-EXP[sec]   g'     Rc     Ic
-----------------------------------------------------
0.11943    14:28:30    6180.0   >19.4  >19.7  >19.5
-----------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]