posted on 2012-10-24, 09:21authored byD. Watson, J. N. Reeves, J. P. Osborne, Jonathan A. Tedds, P. T. O'Brien, L. Tomas, M. Ehle
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.
History
Citation
Astronomy & Astrophysics, 2002, 395 (2), pp. L41-L45
Version
VoR (Version of Record)
Published in
Astronomy & Astrophysics
Publisher
EDP Sciences for European Southern Observatory (ESO)