GCN Circular 19834
Subject
GRB 160821B: NOT optical afterglow candidate
Date
2016-08-22T02:30:07Z (8 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
D. Xu (NAOC/CAS), D. Malesani (DARK/NBI and DTU Space), A. de Ugarte
Postigo (IAA-CSIC, DARK/NBI), E. Gafton, I. Rivero Losada (NOT) report
on behalf of a larger collaboration:
We observed the field of the short GRB 160821B (Siegel et al., GCN
19833) using the 2.56-m Nordic Optical Telescope (NOT) equipped with the
ALFOSC camera. Observations started at 23:02:07 UT on 2016-08-21 (i.e.,
0.548 hr after the burst), and 12 x 300s SDSS r-band frames were
obtained under variable cirrus.
We detected an uncatalogued point source at coordinates:
R.A. = 18:39:54.56
Dec. = +62:23:30.5
with an uncertainty radius of ~0.2 arcsec, which is within the XRT error
circle reported in Siegel et al. (GCN 19833). This source had
R=22.6+/-0.1 mag at 0.95 hr after the burst, calibrated against the star
of R = 17.6 at RA = 18:39:57.59, Dec = +62:22:31.7 in the USNO B1 catalogue.
We also note the presence of a bright, extended, nearby galaxy, 5.5"
away, with a magnitude R ~ 19.2, which is a candidate host galaxy of GRB
160821B.
Lacking variability, we cannot confirm whether the source we identified
is the afterglow of GRB 160821B. Further observations are encouraged.