Author Date

2020-03-20

Degree Name

Department

Physics and Astronomy

College

Physical and Mathematical Sciences

Defense Date

2020-03-10

Publication Date

2020-03-20

First Faculty Advisor

David Neilsen

First Faculty Reader

Eric Hirschmann

Honors Coordinator

Steven Turley

Keywords

gamma-ray burst, GRB, reverse shock, relativistic fluid, relativistic hydrodynamics

Abstract

Gamma-ray bursts (GRBs) are the most luminous electromagnetic phenomena in the universe, but much remains unknown about them. Many models invoked to explain their highly variable light curves are based on complicated dynamics and interactions involving the GRB progenitor but assume simple circumstellar environments. Many long GRBs, however, show late time optical and x-ray flares that may be an indication of a much richer environment. Relativistic hydrodynamics simulations are used to study a family of initial data with a relativistic blast wave encountering a dense circumstellar shell of matter, similar to what an aging star expelling the outer layers of its atmosphere might generate. The possibility that some of this late time curve variability results from these interactions is tested. A characterization of the profiles of the resulting reverse shocks and a preliminary analysis of the subsequent radiation are presented. The results suggests a noticeable increase in the synchrotron spectrum immediately following the interaction and possible infrared and optical emissions due to black-body shortly afterward.

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