| dc.contributor.advisor |
Kumar , Pawan |
en_US |
| dc.identifier.oclc |
221307546 |
en_US |
| dc.creator |
McMahon , Erin Malia , 1980 - |
en_US |
| dc.date.accessioned |
2008 -08 -29T00 :10 :41Z |
|
| dc.date.available |
2008 -08 -29T00 :10 :41Z |
|
| dc.date.created |
2007 |
en_US |
| dc.date.issued |
2008 -08 -29T00 :10 :41Z |
|
| dc.identifier.uri |
http : / /hdl .handle .net /2152 /3790 |
|
| dc.description.abstract |
Although much progress has been made in our understanding of gamma -ray bursts (GRBs ) and their afterglows in the last few decades , some critical questions remain unanswered . One of these questions regards the form in which energy is transported from the explosion to the site at which the gamma -rays are produced - - i .e . is the energy carried in the kinetic energy of electrons and /or protons , or is much of it stored in a magnetic field ? This dissertation documents a series of attempts to more clearly understand the nature of GRB outflows . First , we explore the possibility that the GRB is produced by an external shock , created when a baryonic outflow is decelerated by the surrounding medium . Next , emission from the external reverse shock is used to try to determine if the GRB ejecta is pair enriched . We then use data from several interesting , Swift -detected GRBs pin down the GRB emission radius , bulk Lorentz factor , magnetic field strength , and electron energy . We end by describing our nearly model independent method of modeling the GRB radiation as a combination of synchrontron and synchrontron self -Compton . We find that the GRB is likely to be produced by the syncrontron self -Compton radiation mechanism and predict that the accompanying prompt optical emission should be very high . If bright optical radiation during the GRB is not found , we think that this is good evidence that the acceleration of electrons is taking place repeatedly on a short timescale , effectively ruling out shock -based acceleration models . |
en_US |
| dc.format.medium |
electronic |
en_US |
| dc.language.iso |
eng |
en_US |
| dc.rights |
Copyright © is held by the author . Presentation of this material on
the Libraries' web site by University Libraries , The University of Texas at Austin was made
possible under a limited license grant from the author who has retained all copyrights in
the works . |
en_US |
| dc.subject.lcsh |
Gamma ray bursts |
en_US |
| dc.title |
Gamma -ray bursts and their afterglows : toward a unified model |
en_US |
| dc.description.department |
Astronomy |
en_US |
| dc.identifier.recnum |
b69902446 |
en_US |
| dc.type.genre |
Thesis |
en_US |
| dc.type.material |
text |
en_US |
| thesis.degree.name |
Doctor of Philosophy |
en_US |
| thesis.degree.level |
Doctoral |
en_US |
| thesis.degree.discipline |
Astronomy |
en_US |
| thesis.degree.grantor |
The University of Texas at Austin |
en_US |
| thesis.degree.department |
Astronomy |
en_US |