The Impact of Cosmic Ray and Ionizing Radiation on Galactic Structure and Associated Observational Diagnostics
dc.contributor.author | Holguin, Francisco | |
dc.date.accessioned | 2022-09-06T16:26:35Z | |
dc.date.available | 2022-09-06T16:26:35Z | |
dc.date.issued | 2022 | |
dc.date.submitted | 2022 | |
dc.identifier.uri | https://hdl.handle.net/2027.42/174621 | |
dc.description.abstract | Observations of galaxies have uncovered a complex, multiphase galactic environment structured by the effects of feedback mechanisms within and beyond the galaxy. Still, the exact properties of the galactic and circumgalactic medium remain uncertain. Plasma properties derived from diagnostic ions depend on the ionization mechanism assumed, for example collisional or photoionization. In other words, proper modeling of the radiation field is important. By analyzing cosmological galaxy simulations, I find that that the stellar contribution to the radiation field generally dominates up to roughly 0.1 - 0.2 Rvir, so analyses within that radius should consider stellar sources in ionization assumptions. At the same time, cosmic rays have emerged as a potentially significant feedback mechanism, acting as a non-thermal pressure source, as well as imparting energy and momentum into gas. It is still unclear as to which model of cosmic ray transport is the most realistic. I conduct three dimensional simulations of a section of a Milky Way-like galactic disk. I study a model of cosmic ray transport that includes the effects of the turbulent and magnetized medium, and show that the galactic wind properties are sensitive to the strength of turbulence. Furthermore, I conduct similar galaxy disk section simulations, focusing on both radiative and cosmic ray feedback. I describe methods for producing synthetic spectral line diagnostics from highly-ionized species in simulations and find that models of fast cosmic ray diffusivity without cosmic ray streaming heating best agree with observed diagnostic values. This work illustrates how ultraviolet diagnostics could be useful tools to help differentiate between radiative and cosmic ray feedback models. | |
dc.language.iso | en_US | |
dc.subject | galaxies | |
dc.subject | cosmic ray feedback | |
dc.subject | computational astrophysics | |
dc.title | The Impact of Cosmic Ray and Ionizing Radiation on Galactic Structure and Associated Observational Diagnostics | |
dc.type | Thesis | |
dc.description.thesisdegreename | PhD | en_US |
dc.description.thesisdegreediscipline | Astronomy and Astrophysics | |
dc.description.thesisdegreegrantor | University of Michigan, Horace H. Rackham School of Graduate Studies | |
dc.contributor.committeemember | Ruszkowski, Mateusz | |
dc.contributor.committeemember | Kuranz, Carolyn Christine | |
dc.contributor.committeemember | Gnedin, Oleg Y | |
dc.contributor.committeemember | Hartmann, Lee William | |
dc.contributor.committeemember | Yang, Hsiang-Yi | |
dc.subject.hlbsecondlevel | Astronomy | |
dc.subject.hlbtoplevel | Science | |
dc.description.bitstreamurl | http://deepblue.lib.umich.edu/bitstream/2027.42/174621/1/opaco_1.pdf | |
dc.identifier.doi | https://dx.doi.org/10.7302/6352 | |
dc.identifier.orcid | 0000-0002-8732-5427 | |
dc.identifier.name-orcid | Holguin, Francisco; 0000-0002-8732-5427 | en_US |
dc.working.doi | 10.7302/6352 | en |
dc.owningcollname | Dissertations and Theses (Ph.D. and Master's) |
Files in this item
Remediation of Harmful Language
The University of Michigan Library aims to describe library materials in a way that respects the people and communities who create, use, and are represented in our collections. Report harmful or offensive language in catalog records, finding aids, or elsewhere in our collections anonymously through our metadata feedback form. More information at Remediation of Harmful Language.
Accessibility
If you are unable to use this file in its current format, please select the Contact Us link and we can modify it to make it more accessible to you.