[vsnet-grb-info 7108] GRB 081221: further NOT observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8689
SUBJECT: GRB 081221: further NOT observations
DATE:    08/12/21 22:12:49 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani at astro.ku.dk>

Daniele Malesani, Johan P. U. Fynbo (DARK/NBI), Tapio Pursimo (NOT), and 
Eric Stempels (Univ. St. Andrews) report on behalf of a larger 
collaboration:

Further to what reported in GCN 8688, we observed the field of GRB 
081221 (Hoversten et al., GCN 8687) in the I and z filters with the NOT 
equipped with ALFOSC. Exposure times were 18 and 16 min, respectively, 
with mean times Dec 21.844 and Dec 21.863 UT (3.89 and 4.37 hr after the 
GRB, respectively).

Inside the XRT error circle reported by Hoversten et al. (GCN 8687), we 
do not detect any source in either filters. The limiting magnitude is I 
~ 23 assuming I = 17.65 for the USNO star at RA = 01:03:09.59, Dec = 
-24:32:45.0.

We encourage deeper searches of the optical/NIR counterpart of this 
event, which had a bright gamma- and X-ray prompt emission.