GCN Circular 2649
Subject
XRF040812: possible afterglow
Date
2004-08-18T15:57:39Z (20 years ago)
From
Sergio Campana at INAF-OAB <campana@merate.mi.astro.it>
S. Campana and A. Moretti (INAF-Osservatorio di Brera) report:
"We analyzed the Chandra ACIS-S data of the XRF040812 (Gotz et al. 2004,
GCN 2640) region. We carried out spectral analysis of the second source
(CXOJ162602.3-444349) in the Patel et al. (2004, GCN 2648), the only one
with a sizable number of counts. The source is extremely hard with a
photon index of 0.1+\-0.6 (90% confidence level), fixing the column
density to the Galactic value of 5.3x10^21 cm-2. Leaving free the column
density the error on the photon index increases to 0.1_(-1.0)^(+1.5).
This hard photon index is typical of GRB X-ray afterglows. The
unabsorbed 0.5-10 keV source flux is 2.53E-13 erg cm-2 s-1. The
following Chandra observation (August 22, 2004) will allow to assess
the afterglow nature of CXOJ162608.4-444125."
We acknowledge the extraordinary effort by the CXC in providing rapid
processing of this challenging data-set, thereby enabling this report.
This message can be cited.