Kann 2007 Swift Optical afterglows
主要内容:
Data gathering.
精彩摘抄:
Some energetics
Light curves
E_iso,bol distribution
文章信息: The Afterglows of Swift-era Gamma-Ray Bursts. I. Comparing pre-Swift and Swift era Long/Soft (Type II) GRB Optical Afterglows
(Submitted on 13 Dec 2007)
Abstract: We have gathered optical photometry data on a large sample of Swift-era gamma-ray burst (GRB) afterglows. We analyzed their light curves and derive spectral energy distributions for the sample with the best data quality, allowing us to derive the host galaxy extinction. We transform the afterglow light curves into an extinction-corrected $z=1$ system and compare their luminosities with a sample of pre-Swift afterglows. We find that the luminosity distribution of the two afterglow samples are very similar, and that a fainter sample can be explained by a moderate amount of line-of-sight host extinction. We derive bolometric isotropic energies for all GRBs in our sample, and find only a tentative correlation between the prompt energy release and the optical afterglow luminosity. Furthermore, we propose the existence of an upper ceiling on afterglow luminosities and study the luminosity distribution at early times, which was not accessible before the advent of the Swift satellite. Finally, we postulate the existence of an intermediate class of long GRBs which lie between the typical high-luminosity, high-redshift events described in the rest of the paper and nearby low-luminosity events associated with spectroscopic SNe in terms of energetics and redshift distribution.
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