The X-ray afterglow of GRB 020322
Abstract
The spectrum of the afterglow of GRB 020322 is the highest-quality X-ray spectrum of a GRB afterglow available to date. It was detected by XMM-Newton in an observation starting fifteen hours after the GRB with a mean 0.2-10.0 keV observed flux of 3.5+/-0.2*E-13 erg cm-2 s-1, making it the brightest X-ray afterglow observed so far with XMM-Newton. The source faded; its lightcurve was well fit by a power-law with a decay index of 1.26+/-0.23. The spectrum is adequately fit with a power-law absorbed with neutral or ionised gas significantly in excess of the foreground Galactic column, at redshift 1.8-1.1+1.0 or with low metal abundances. No spectral line or edge features are detected at high significance, in particular, a thermal emission model fits the data poorly, the upper limit on its contribution to the spectrum is 3.7*E-14 erg cm-2 s-1, or ~ 10% of the total flux. No spectral variability is observed.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- November 2002
- DOI:
- 10.1051/0004-6361:20021501
- arXiv:
- arXiv:astro-ph/0210328
- Bibcode:
- 2002A&A...395L..41W
- Keywords:
-
- gamma rays: bursts;
- X-rays: general;
- Astrophysics
- E-Print:
- 5 pages, 3 figures, accepted for publication in A&