The X-ray afterglows of gamma-ray bursts GRB 001025A and GRB 010220 observed with XMM-Newton
Santos-Lleó, M.; Ehle, M.; Watson, D.; O'Brien, P. T.; Reeves, J. N.; Tedds, J. A.; Pounds, K. A.; Osborne, J.
United Kingdom, Spain
Abstract
The X-ray afterglows of GRB 001025A and GRB 010220 were detected by XMM-Newton with an average 0.2-10.0 keV flux of 4.4 and 3.3*E-14 erg cm-2 s-1 respectively; the afterglow of GRB 001025A is observed to decay. Afterglows at other wavelengths were not detected for either burst. A set of broadened soft X-ray emission lines are detected in the afterglow of GRB 001025A, at 5.0 sigma significance above a Galactic-absorbed power-law continuum. The spectra of both afterglows are significantly better fit by a variable abundance thermal plasma model than by an absorbed power-law and are consistent with the observations of GRB 011211, indicating that thermal emission from light elements may be common in the early X-ray afterglows of GRBs.