DOI

10.17077/etd.tj4r-mvx0

Document Type

Dissertation

Date of Degree

Summer 2019

Degree Name

PhD (Doctor of Philosophy)

Degree In

Physics

First Advisor

Kaaret, Philip E.

First Committee Member

Spangler, Steven R.

Second Committee Member

Lang, Cornelia C.

Third Committee Member

Gayley, Kenneth G.

Fourth Committee Member

Finley, John P.

Abstract

The constant flux of cosmic rays that bombard Earth from within our own galaxy are understood to come from both shell-type supernova remnants and pulsar wind nebulae (PWNe). Multiwavelength study of these objects can help us to understand what types of particles are accelerated, and gamma-ray emission is key to understanding the highest energy cosmic rays. In this thesis, I analyze and interpret observations made with the Very Energetic Radiation Imaging Telescope Array System (VERITAS), a gamma-ray telescope located in Southern Arizona.

LS 5039 and HESS J1825-137 occupy the same field of view on the sky and were observed for about 8 hours with VERITAS. LS 5039 is a gamma-ray binary, and the observations supports theories that the compact object hosts a PWN which is continuously interacting with the nearby star. HESS J1825-137 is a very extended PWN with an extent of diameter greater than 1 degree on the sky. Using the VERITAS observations, I am able to measure the radial profile and compare the gamma-ray luminosity to other PWN.

DA 495, a "Crab-like" PWN with unusually strong magnetic fields, was observed for about 70 hours with VERITAS. In this study, results are combined with radio and X-ray spectral information to allow for detailed astrophysical modeling of the region. This broadband spectral modeling places constraints on the properties of the particle population in this PWN and allows for both leptonic and hadronic emission scenarios to be evaluated. Hadronic scenarios instil doubt on the pure PWN interpretation and favor a previously undetected shell-type remnant being present.

Keywords

gamma-ray astronomy, particle acceleration, pulsar wind nebula, supernova remnants

Pages

xi, 107 pages

Bibliography

Includes bibliographical references (pages 96-107).

Copyright

Copyright © 2019 Patrick Dean Wilcox

Included in

Physics Commons

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