[vsnet-grb-info 4357] GRB 070224: optical afterglow candidate

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6142
SUBJECT: GRB 070224: optical afterglow candidate
DATE:    07/02/25 05:02:38 GMT
FROM:    Christina Thoene at Niels Bohr Institute,DARK Cosmo Ctr  <cthoene at astro.ku.dk>

Christina C. Thoene (DARK), D. Alexander Kann (TLS Tautenburg) and Thomas
Augusteijn (NOT) report:

We observed the field of GRB 070224 (GCN 6137) with NOT and StanCAM in R
and I filters starting 4.35h after the burst.

In 3x300s stacked images, we detect a faint object in both R and I close
to the XRT error circle at

RA = 11:56:06.68
Dec = -13:19:47.6 (J2000)

with conservative errors of 1".
This is about 5 arcseconds from the refined XRT error circle center (GCN
6143).

We propose this object to be the optical afterglow of GRB 070224.
At the moment, we cannot confirm if the object is fading or not. Further
observations are planned.