Date of Award

2013

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Physics

Committee Chair

Massimillano Bonamente

Committee Member

Douglas Swartz

Committee Member

Robert Preece

Subject(s)

Stars--Evolution., Galaxies--Evolution., Chandra x-ray observatory (U.S.), X-ray astronomy., X-ray telescopes.

Abstract

Early X-ray studies found a strong, empirical correlation with far infrared emission. This lead to using X-ray emission as a star formation rate tracer. The X-ray observations at that time had poor spatial resolution and thus didn't allow individual fainter sources to be identified. More recent observations with Chandra allowed deeper observations as well as the ability to identify fainter point sources. With these advancements, the ratio between X-ray and far infrared luminosity was found to decrease with increasing far infrared. One possible explanation is higher X-ray extinction in luminous or ultra-luminous infrared galaxies due to more atomic hydrogen, thus driving down the total observed X-ray luminosity. Since these galaxies are rare and very far away, they are still point like even with today's X-ray observations so we cannot spatially resolve them. Another explanation to the ratio decrease is more star formation rate independent contributions in the lower far infrared luminosity regime. This can be addressed by identifying the star formation rate dependent and independent components which is the purpose of this study. Using Chandra data, star formation rate dependent and independent components were analyzed for 7 galaxies from the Arp Atlas. After correcting for absorption and estimating the contributions from star formation rate dependent and independent components, a decrease was still found in the high far infrared regime. This could be due to a difference in evolutionary time between X-rays and far infrared emission.

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