EDP Sciences
Free access
Issue
A&A
Volume 395, Number 2, November IV 2002
Page(s) L41 - L45
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20021501


A&A 395, L41-L45 (2002)
DOI: 10.1051/0004-6361:20021501

Letter

The X-ray afterglow of GRB 020322

D. Watson1, J. N. Reeves1, J. P. Osborne1, J. A. Tedds1, P. T. O'Brien1, L. Tomas2 and M. Ehle2

1  X-ray Astronomy Group, Dept. of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UK
2  XMM-Newton Science Operations Centre, European Space Agency, PO Box 50727, 28080 Madrid, Spain

(Received 27 September 2002 / Accepted 14 October 2002)

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 $3.5\pm0.2\times10^{-13}$ 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 $1.26\pm0.23$. 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 $3.7\times10^{-14}$ erg cm -2 s -1, or ~10% of the total flux. No spectral variability is observed.


Key words: gamma rays: bursts -- X-rays: general

Offprint request: D. Watson, wat@star.le.ac.uk

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