Dissertation
An x-ray study of the effects of stellar feedback on galaxy evolution and structure
University of Iowa
Doctor of Philosophy (PhD), University of Iowa
Summer 2022
DOI: 10.25820/etd.006473
Abstract
Stars and star formation regions within a galaxy can have a significant effect on the properties of that galaxy. The engine driving these changes is feedback produced by the birth, life, and death of these stars. Feedback describes the effect of energy and momentum being ejected from a source back into the greater galaxy. Evidence of these feedback sources and the changes they cause can be detected in X-ray observations of galaxies. In this thesis we examine these effects in a fewways. First, we look at X-ray observations of the circumgalactic medium (CGM), the hot gas and plasma surrounding the disk of our Galaxy. The CGM is found to have a patchy distribution, reflecting contributions from feedback processes in the disk. Second, we analyze the Cygnus Superbubble (CSB), a large X-ray structure in the Galactic disk. Due to consistent properties across the structure, the CSB is found to likely be a cohesive structure, potentially a hypernova remnant. This would make it the only known example of a hypernova remnant in our Galaxy, and a significant feedback source. Finally we look at X-ray sources in a set of 8 low-metallicity galaxies, finding X-ray sources in 5 of these galaxies, 4 of which are notably luminous. These sources are all likely to be X-ray binaries, potentially powerful feedback engines. Evidence is found that the galaxies with these X-ray sources are depleted in dust, potentially because of feedback from the X-ray sources.
Details
- Title: Subtitle
- An x-ray study of the effects of stellar feedback on galaxy evolution and structure
- Creators
- Jesse Bluem
- Contributors
- Philip E Kaaret (Advisor)Casey T DeRoo (Committee Member)Kenneth Gayley (Committee Member)Keri Hoadley (Committee Member)Keith M Jahoda (Committee Member)
- Resource Type
- Dissertation
- Degree Awarded
- Doctor of Philosophy (PhD), University of Iowa
- Degree in
- Physics
- Date degree season
- Summer 2022
- Publisher
- University of Iowa
- DOI
- 10.25820/etd.006473
- Number of pages
- ix, 102 pages
- Copyright
- Copyright 2022 Jesse Bluem
- Language
- English
- Description illustrations
- color illustrations
- Description bibliographic
- Includes bibliographical references (pages 94-102).
- Public Abstract (ETD)
Galaxies are massive structures containing billions of stars. These stars can put out enough energy, alone or in groups, to have a significant effect on their surroundings. We refer to this effect as feedback. Stars produce feedback throughout their lifespan. When massive stars reach the end of their life they explode in super-novae that are also a significant feedback source. Stellar remnants, black holes and neutron stars, left behind can also continue to contribute feedback. In this thesis we study these feedback effects using X-ray observations. First, we study the diffuse gas in the outer layers of our Galaxy, finding it to be patchy. This patchiness likely reflects the uneven star formation and therefore feedback within the Galaxy. Second, we analyze a large region in our Galaxy called the Cygnus Superbubble (CSB). We find that the CSB appears to be a singular object, and is likely an exceptional example of a supernova and thus a significant source of feedback. Third, we look at a set of 8 galaxies outside of our own. We find evidence of bright stellar remnants in 5 of these galaxies. The galaxies with these remnants appear to be less dusty, potentially because of significant feedback from the remnants.
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984285453102771
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