GCN Circular 6847
Subject
GRB 071003: Possible rebrightening
Date
2007-10-04T08:33:56Z (17 years ago)
From
Daniel Perley at U.C. Berkeley <dperley@astro.berkeley.edu>
D. A. Perley, W. Li, J. S. Bloom (UC Berkeley), C. Fassnacht (UC Davis),
and P. Nugent (LBL) report:
On the night of 2007-10-04 (UT) we imaged the field of GRB 071003 with
Keck I + LRIS, in g+R filters simultaneously for 3 exposures of 300
seconds, starting at 04:49 UT.
We detect at the position reported by Li (GCN 6838) a bright source with
an estimated magnitude of R~20, though photometry is complicated by the
presence of the nearby 11th magnitude star. The position is consistent
within 0.3" of the KAIT detection, strongly suggesting that this is the
same source. Given the rapid fading noted in earlier circulars (GCN
6841, GCN 6844) and the limit of R > 21 reported by Shih et al. (GCN
6848) this may suggest that the optical afterglow is rebrightening,
either due to a late-time flare or a rising low-redshift supernova.
We also note what appears to be a faint, extended object approximately
2" to the southwest of the afterglow (towards the bright star), which
may be the host galaxy of this burst.
Further analysis is in progress. Additional observations are strongly
encouraged to further examine the nature of this transient.