Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Electronic On-line Article (HTML)
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
X-ray flares in Gamma-Ray Bursts
Authors:
Morris, David C.
Affiliation:
AA(The Pennsylvania State University)
Publication:
Proquest Dissertations And Theses 2008. Section 0176, Part 0606 335 pages; [Ph.D. dissertation].United States -- Pennsylvania: The Pennsylvania State University; 2008. Publication Number: AAT 3325952. Source: DAI-B 69/08, Feb 2009
Publication Date:
00/2008
Origin:
UMI
Keywords:
X-ray flares, Gamma-ray bursts
Comment:
Publication Number: AAT 3325952; ISBN: 9780549774358
Bibliographic Code:
2008PhDT........28M

Abstract

Data from the Swift mission have now shown that flares are a common component of Gamma-Ray Burst afterglows, appearing in roughly 50% of GRBs to which Swift slews promptly and in all phases of GRBs. Much has been learned from analysis of individual flares and from the recent first GRB flare surveys (Falcone et al. (2007); Chincarini et al. (2007)) which have focused primarily on properties of the X-ray emission from flares. The broadband spectral properties of flares, however, particularly at UV and optical wavelengths, have yet to be systematically studied. In this thesis, I discuss results from a multiwavelength survey of bright X-ray selected flares seen in Swift GRBs. Using simultaneous data from the UVOT, XRT and BAT, I have produced SEDs of flares from 0.002 keV to 150 keV and fit them using several different spectral models. My results show that a simple absorbed powerlaw is unable to fit flare spectra in the 0.002 keV to 150 keV energy range due, in large part, to a very low UV/X-ray emission ratio. I furthermore investigate the applicability to the data of several models for GRB flare production from the literature. I find that the internal shock model of flare production is the most likely model to explain any given flare, but that no single model is able to explain the complete taxonomy of GRB X-ray flares. I determine the approximate fraction of flares which are explained by each mechanism. I also use the flares in my sample to investigate the bulk Lorentz factor of GRB flares and to compare it to the bulk Lorentz factor of the prompt GRB emission. I find a likely range for the Lorentz factor of flares of 10 < G < 30, significantly lower than the canonical value for the prompt emission of G < 300. Finally, I also investigate a discovered trend between the amount of flaring activity in GRBs and redshift.
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
   

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints