TITLE:   GCN CIRCULAR
NUMBER:  19572
SUBJECT: GRB 160623A: MITSuME Ishigakijima Optical Observation
DATE:    16/06/25 02:37:27 GMT
FROM:    Daisuke Kuroda at OAO/NAOJ  <dikuroda@oao.nao.ac.jp>

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 160623A (Vianello et al., GCNC 19553;
Tiengo et al., GCNC 19559) 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 2016-06-23 15:14:25 UT (~10.2 h after
the burst). We detected the previously reported afterglow
(Pozanenko et al., GCNC 19561; Butler et al., GCNC 19567) in
Rc and Ic bands.

Three sigma upper limit and photometric results of the OT are
listed below. We used GSC2.3 catalog for flux calibration.

#T0+[day]  MID-UT    T-EXP[sec]   g'    Rc   Rc_err  Ic   Ic_err
------------------------------------------------------------------
0.42989    15:19:37     540.0    >20.4  18.63 0.06   17.19 0.06
0.45924    16:01:53     480.0    >20.4  18.86 0.09   17.63 0.11
------------------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]