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The X-ray afterglow of GRB 020322

D. Watson·J. N. Reeves·J. P. Osborne·J. A. Tedds·P. T. O'Brien·L. Tomas·M. Ehle
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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+/-0.2x10^-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 3.7x10^-14 erg cm^-2 s^-1, or at most ~10% of the total flux. No spectral variability is observed.

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D. Watson, J. N. Reeves, J. P. Osborne, J. A. Tedds, P. T. O'Brien, L. Tomas, M. Ehle. 2002-10-15. The X-ray afterglow of GRB 020322. https://doi.org/10.1051/0004-6361%3A20021501

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