TITLE:   GCN CIRCULAR
NUMBER:  19400
SUBJECT: GRB 160506A: IRSF upper limits
DATE:    16/05/07 01:59:55 GMT
FROM:    Katsuhiro L. Murata at Nagoya U  <murata@u.phys.nagoya-u.ac.jp>

K. L. Murata (Nagoya U.), Y.-H. Lee, B.-C. Koo (Seoul National U.), and T.
Nagayama (Kagoshima U.)

We observed the field of GRB 160506A ( Hagen et al., GCN Circular #19394)
with the near-infrared (J, H, Ks) simultaneous imaging camera SIRIUS
attached to 1.4 m telescope IRSF ( InfraRed Survey Facility) in Sutherland
observatory, South Africa. We observed with a narrow band filter with
double transmissions at 1.189 um and 1.644 um.

The observations started on 2016-05-06 04:18:47 UT (~ 49 min. after the
burst). We could not detect the afterglow within the XRT error circle
reported in the GCN circular. We have obtained the following preliminary
upper limits (Vega magnitude system):
 M_1.189um > 17.3 mag
 M_1.644um > 16.6 mag

Given magnitudes of M_1.189um and M_1.644um were calibrated against J band
and H band of 2MASS point sources in this field, respectively. The upper
limits were determined as the magnitudes of the faintest star within 1
arcmin from the XRT position.

This observation was carried out by IRSF and OISTER collaboration.