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Stellar Feedback in Galaxies, Its Impact on the Circumgalactic Medium, and the Importance of Radiative Cooling

Lochhaas, Cassandra Derrick
http://rave.ohiolink.edu/etdc/view?acc_num=osu1562676332648711

Abstract Details

2019, Doctor of Philosophy, Ohio State University, Astronomy.
The circumgalactic medium (CGM) is the conduit between galaxies and their large-scale environments, and both affects and is affected by the evolution of the galaxy. In particular, stellar feedback that launches large-scale galactic winds can restructure the CGM and seed it with cool gas, potentially explaining why CGM surveys ubiquitously find a large mass of cool gas with no clear origin. I show that an analytic model for a galactic wind bubble propagating into the CGM can cool radiatively to produce the large mass of cool gas observed and the mass budget, physical scale, velocities, and metallicities are shown to match the observations well. By analyzing a high signal-to-noise spectrum of a quasar behind two foreground galaxies, I find that the warm gas in the CGM cannot be in collisional ionization equilibrium and must instead be produced in dynamic processes, such as the radiative cooling of large-scale winds in the wind bubble model. A detailed analysis of high-resolution simulations of the CGM in both high- and low-mass halos shows that while a high-mass halo can be described following the standard picture, as a hot gas halo in pressure equilibrium with condensing cold clouds, whereas a low-mass halo is not in equilibrium and is instead dominated by cooling bulk gas flows rather than turbulent motions. These three results, across the domains of analytics, observations, and simulations, suggest that radiatively cooling galactic winds play a pivotal role in the structure and evolution of the CGM. On smaller scales, I show that a heavily mass-loaded wind radiatively cools within a wind-driving region, such as a star cluster, which can both inhibit the wind that escapes from the cluster and lead to additional generations of stars to form out of the stellar wind material of the first generation. Radiative cooling predicts a maximum on hot, supernova-driven wind momentum that agrees well with wind observations and can be used to inform galaxy formation simulations. On larger scales, I show that dense reservoirs of gas in the universe are correlated in location with galaxies, and mock observations from large-scale structure simulations can be used to characterize the environments of observed galaxies. Overall, these results represent several forays into understanding the interaction of galactic winds with galactic environments using a variety of methods.
Todd Thompson (Advisor)
David Weinberg (Committee Member)
Laura Lopez (Committee Member)
346 p.
Astronomy; Astrophysics
galaxies; galactic winds; circumgalactic medium; astronomy

Recommended Citations

Citations

  • Lochhaas, C. D. (2019). Stellar Feedback in Galaxies, Its Impact on the Circumgalactic Medium, and the Importance of Radiative Cooling [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1562676332648711

    APA Style (7th edition)

  • Lochhaas, Cassandra. Stellar Feedback in Galaxies, Its Impact on the Circumgalactic Medium, and the Importance of Radiative Cooling. 2019. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1562676332648711.

    MLA Style (8th edition)

  • Lochhaas, Cassandra. "Stellar Feedback in Galaxies, Its Impact on the Circumgalactic Medium, and the Importance of Radiative Cooling." Doctoral dissertation, Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1562676332648711

    Chicago Manual of Style (17th edition)

osu1562676332648711
409
© 2019, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.