GCN Circular 2683
Subject
GRB 040827: 2nd epoch of Magellan K-band imaging
Event
Date
2004-08-29T03:08:22Z (21 years ago)
From
Edo Berger at Carnegie Obs <eberger@ociw.edu>
D.L. Kaplan (MIT) and E. Berger (Carnegie Observatories) report:
"We again imaged the position of the XMM-Newton X-ray source (GCN #2678),
localized inside the error circle of GRB 040827 (GCN #2672), with the
PANIC instrument on the Magellan Baade 6.5-m Telescope. A total of 36
minutes were obtained in the Ks-band on Aug. 28.97 UT with a seeing of
about 1". A comparison to images obtained on the previous night by
Gladders and Berger (GCN #2681) reveals that XMM-1 has not faded and
remains steady at Ks~19.4 mag. XMM-2 appears fainter by about 0.5 mag,
but this may be due to the poorer seeing conditions (1" compared to 0.55"
on Aug. 28.02 UT) and the extended nature of this source. The lack of
variability (see also GCN #2682) casts doubt on the identity of XMM-1 as
the afterglow of GRB 040827. Further observations of XMM-2 in the NIR
are encouraged."