The Early X-ray Afterglow Spectra of GRBs from Swift
Abstract
The mounting Swift XRT data set is unparalleled in its time sampling and exposure (>10^7s) of the early (t<1 day) X-ray afterglows. We have performed time-resolved spectral fitting of the data, including data for many bright X-ray flares. We have conducted a thorough and blind search for emission lines in the spectra as well. In most cases, the afterglows are consistent with pure power-laws plus extinction. Significant outliers to the population exist at the 5-10% level and have anomalously soft, possibly thermal spectra. There appears to be strong spectral evolution evident during many of the bright flares. We discuss these spectra in the context of external shock afterglow and GRB emission models and in the context of the debate over emission line detections.
- Publication:
-
AAS/High Energy Astrophysics Division #9
- Pub Date:
- September 2006
- Bibcode:
- 2006HEAD....9.1603B