[vsnet-grb-info 7590] GRB 090417B: Subaru NIR Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9145
SUBJECT: GRB 090417B: Subaru NIR Observations
DATE:    09/04/18 09:53:27 GMT
FROM:    Nobuyuki Kawai at Tokyo Tech  <nkawai at hp.phys.titech.ac.jp>

K. Aoki, I. Tanaka, F. Nakata (Subaru Telescope), K. Ohta, S. Yuma (Kyoto U),
and N. Kawai (Tokyo Tech) report on behalf of the Subaru GRB team:

We observed the field of GRB 090417B (Sbarufatti et al. GCN 9135)
with MOIRCS on Subaru Telescope in J band Ks bands under a
cirrus condition.
The observing period is from 05:00 UT to 07:45 UT on April 18th,
about 15 hours after the burst.
In the XRT error circle, we detected the object reported
by Fynbo et al. (GCN 9140).
Roughly estimated J and Ks magnitudes of this object relative
to a nearby 2MASS star are 20.0 mag and 18.5 mag (Vega), respectively.
The object seems to be point-like under the seeing condition of
0."7, though the S/N is not so good to be definitive.
No other sources are found in the error circle.

The GRB may be a dusty GRB in the galaxy seen in the SDSS image,
or might be a high redshift GRB that appeared far behind the galaxy,
or intrinsically very faint.