TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  2497
SUBJECT: GRB 031220: Subaru observation
DATE:    03/12/21 04:08:58 GMT
FROM:    Nobuyuki Kawai at Tokyo Tech  <nkawai@hp.phys.titech.ac.jp>

G. Kosugi, Y. Ohyama, T. Yamada, K. Sekiguchi, T. Sasaki, M. Akiyama,
and N. Kawai report on behalf of the Subaru GRB team:

"We have observed the field covering most of the SXC error box of 
GRB 031220 (=H2976) in I band with FOCAS on the Subaru 8.2m telescope
on Mauna Kea beginning at 11:20 UT on Dec 20, approximately 8 hours after
the burst.  The field was covered with 5 pointings of 10 min exposure,
with average seeing of 0.9 arcseconds.

Visual comparison with DSS-2 images revealed no obvious counterpart
candidates."