GCN Circular 2345
Subject
XRF 030723: Detection of a rebrightening in the optical afterglow
Event
Date
2003-08-06T18:38:00Z (23 years ago)
Edited On
2026-04-24T17:48:49Z (6 months ago)
From
Jens Hjorth at U.Copenhagen <jens@astro.ku.dk>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov>
J. P. U. Fynbo (U. Aarhus), J. Hjorth (U. Copenhagen), J. Gorosabel
(IAA-CSIC/STScI), B. L. Jensen (U. Copenhagen), M. I. Andersen (AIP),
R. A. M. J. Wijers (U. Amsterdam), C. Kouveliotou (NASA/MSFC), on behalf
of GRACE, report:
"We have monitored the afterglow of XRF 030723 (Prigozhin et al. GCN #2313;
Fox et al. GCN #2323; Butler et al. GCN #2328) with the ESO VLT. Between
Aug 3.2 UT and Aug 6.3 2003 UT the optical afterglow brightened by 1.0 mag
to R ~ 24.3. If this is due to the emergence of a supernova it would
strengthen the link between GRBs and XRFs. It would also indicate a fast rise
for the supernova and a relatively low redshift for XRF 030723, z < 1,
consistent with the earlier spectroscopic constraints (Fynbo et al.
GCN #2327). Alternatively, we may be seeing a rebrightening due to late
energy injection (refreshed shock). Continued spectroscopic and photometric
monitoring is planned.
Images are posted at http://www.astro.ku.dk/~brian_j/grb/grb030723
We thank the Paranal Observatory staff for efficiently conducting the
reported service-mode observations."