[vsnet-grb-info 8413] GRB090904B : IRSF NIR upper limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9931
SUBJECT: GRB090904B : IRSF NIR upper limit
DATE:    09/09/25 02:00:32 GMT
FROM:    Kenta Nishimoto at Nagoya U/MOA-II  <nishimo at stelab.nagoya-u.ac.jp>

K. Nishimoto, T. Sako(Nagoya Univ.) on behalf of the MOA Collaboration,
M. Kurita on behalf of the IRSF Collabration, T. Yosikawa(Kyoto Univ.),
T. Suenaga(Soken Univ.) report:

We searched for a NIR afterglow of GRB090904B (GCN9881, V. D'Elia et
al.) starting from 17:6:57.7 UT on 2009 Sep 4 (15.71 hours after the burst)
with the SIRIUS on the IRSF 1.4m telescope at SAAO in South Africa.
In images of a 300sec exposure with J, H and Ks filter, we did not find
any object except the reported star (GCN9882, Covino et al and GCN9892,
Nishimoto et al.) within the error circle of the Swift XRT source
position (GCN9887, J.P. Osborne et al.).

Quick estimation of the limiting magnitude calibrated by using 2MASS
catalog:

J > 17.14
H > 16.57
K > 15.79