Feedback in dwarf galaxies

Thesis

Stellar feedback processes have been suggested as a mechanism for explaining various properties of galaxies, especially dwarf galaxies, which have weaker potentials and thus lower escape velocities for galactic winds. In this thesis, I present work done during my DPhil to better understand these processes. I begin by discussing the techniques used to simulate galaxies as collections of astrophysical fluids in a cosmolog- ical context, and present some methods for interpreting the results of such simulations. I then present two projects aimed at furthering our understanding of feedback in dwarf galaxies.

The first project is the investigation of a suite of simulations of satellites of a Milky Way-class halo. We discuss the formation of high-redshift dwarf galaxies and the effect that supernova feedback and reionisation have on the gas content and star formation history of these objects. We find that neither process has a dramatic effect on the star formation rates in high redshift dwarf galaxies that have already begun forming stars prior to reionisation. We do find, however, that the population of satellites is dramatically altered by the presence of cooled gas in the host halo, which increases the tidal stripping of satellites that pass close to the host. The second project concerns detailed simulations of a 15 solar mass star throughout its evolution, studying photoionisation, wind and supernova feedback from this star in various environments. Preliminary results are given for these simulations, which are compared to the results of previous authors.

Authors: Geen, S; Samuel Thomas Geen

• Publication date: 2012
• DOI: 10.5287/ora-bmvbebqza
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: numerical astrophysics; galaxies; astrophysics
• Subjects: Astrophysics