TITLE:   GCN CIRCULAR
NUMBER:  19482
SUBJECT: GRB 160601A: MITSuME Okayama Ks-band upper-limit
DATE:    16/06/01 17:09:41 GMT
FROM:    Kenshi Yanagisawa at OAO/NAOJ  <yanagi@oao.nao.ac.jp>

K. Yanagisawa, D. Kuroda, Y. Shimizu, H. Izumiura(OAO/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 160601A (Kocevski et al., GCN 19478)
in Ks-band with a wide-field near infrared imager at Okayama
Astrophysical Observatory (Japan).  The imager has effective
aperture of 0.91 m.

Observations started from 14:57 UT on 1st June, 14 min after
the BAT trigger, to 15:22 UT. The total exposure of 10.0 min
was successfully obtained.

In our co-add image, we did not find any new point source within
the XRT error circle down to the limiting magnitude of
Ks=16.1 (Vega, S/N=3). The photometric calibration was made
against 2MASS field stars.

T0+[sec]    MID-UT     T-EXP[sec]      Ks
---------------------------------------------------
   +1,560    15:09      600.0          >16.1
---------------------------------------------------
T0+ : Elapsed time after the burt [sec]
T-EXP: Total Exposure time [sec]