[vsnet-grb-info 16832] GRB 150727A: IRSF NIR observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18113
SUBJECT: GRB 150727A: IRSF NIR observation
DATE:    15/08/04 08:45:32 GMT
FROM:    Daisuke Kuroda at OAO/NAOJ  <dikuroda at oao.nao.ac.jp>

K. L. Murata (Nagoya U.), T. Kusune (Nagoya City U.), H. Onozato (Tohoku U.) and T. Nagayama (Kagoshima U.)

We observed the field of GRB 150727A (Cenko et al., GCN Circular #18076) with the near-infrared (J, H, Ks) simultaneous imaging polarimeter SIRPOL attached to 1.4 m telescope IRSF (InfraRed Survey Facility) in Sutherland observatory, South Africa.

The observations started on 2015-07-27 19:25:30 UT (~ 9 min. after the burst).
We detected an uncatalogued source within 5 arcsec from the Swift/UVOT preliminary position reported in the GCN circular of Breeveld et al. (GCN Circular #18084).
We have obtained the following preliminary magnitude (Vega magnitude system):

J   = 18.9 +- 0.2
H   = 18.1 +- 0.1
Ks  = 17.1 +- 0.2

Given magnitudes were calibrated against 2MASS point sources in this field.

This observation was carried out by IRSF and OISTER collaboration.