TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  2522
SUBJECT: GRB031203: Chandra Observations
DATE:    04/01/26 01:23:00 GMT
FROM:    Derek Fox at CIT  <derekfox@astro.caltech.edu>

D.B. Fox, A.M. Soderberg, and S.R. Kulkarni (Caltech), with D. Frail
(NRAO) report:

"We have observed the X-ray afterglow of GRB031203 (Tedds et al., GCN
2490) with the Chandra X-ray Observatory, in a single 21.6 ksec
exposure beginning at 21:35 UT on 22 January 2004 (mean epoch 49.1
days post-burst).  At the XMM position derived by Tedds et al. (GCN
2490) we observe a single point-like source with a net count rate of
0.56 +/- 0.16 counts per ksec.  Converting this count rate into a flux
using the power-law (index 1.7) spectrum found by Vaughan et al. (GCN
2489), and assuming a hydrogen column of 6.2E+21 cm**-2, we find a
2-10 keV X-ray flux of approximately 6.4E-15 erg cm**-2 s**-1.  This
corresponds to a power-law decay from the last epoch of XMM
observations (approx. 3.6 days post-burst) of index alpha = -1.0 +/-
0.1."