Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
Introducing Einstein Probe, Astro Flavored Markdown, and Notices Schema v4.0.0. See news and announcements

GCN Circular 19834

GRB 160821B: NOT optical afterglow candidate
2016-08-22T02:30:07Z (8 years ago)
Dong Xu at NAOC/CAS <>
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 

Lacking variability, we cannot confirm whether the source we identified 
is the afterglow of GRB 160821B. Further observations are encouraged.
Looking for U.S. government information and services? Visit