Small Galaxies in a Wide-Field Era: On the Interplay Between the Structure of Low-Mass Galaxies and the Processes that Shape Them

Abstract

Low-mass "dwarf" galaxies, galaxies with stellar masses less than one billion solar masses, are key testbeds for many contemporary problems in astrophysics. The shallow potential wells of these low-mass systems make their structure particularly sensitive to physical processes at both sub-galactic and super-galactic scales; dwarfs in the mass range of about ten million to one billion solar masses are key testbeds for our understanding of star formation physics, galaxy interactions, and dark matter. However, due to their low luminosities, it is only recently that wide-field surveys have reached the requisite depth and spatial resolution to probe the dwarf population at distances beyond a few tens of Mpc. In this thesis, I develop new data analysis methods to fill the gaps in our knowledge of low-mass galaxies using modern wide-field surveys, focusing particularly on the interconnected nature of star formation, galaxy interactions, and their respective impacts on galaxy structure. I first provide an abbreviated introduction to the history of the observation and cataloging of dwarf galaxiesin Chapter 1. Chapter 2 and Chapter 3 center around the detection and classification of extragalactic tidal debris -- the first focuses on high mass-ratio encounters between low-mass and massive galaxies, while the second focuses on roughly equal mass mergers between dwarfs. Chapter 4 and Chapter 5 develop and deploy statistical tools to measure the three dimensional shape of dwarf galaxies for both a spectroscopic sample of high surface brightness dwarfs and a sample of Low Surface Brightness Galaxies. Chapter 6 goes on to compare the three dimensional structure of these observed dwarf galaxies to that of the simulated dwarfs in the FIRE-2 cosmological zoom suite. Chapter 7 maps out the star formation rate and star formation efficiency of a sample of Ultra Diffuse Galaxies and "normal" dwarfs, while Chapter 8 considers the physical picture of star formation in these galaxies in the model of pressure-regulated, feedback-modulated star formation. Finally, Chapter 9 gives a short overview of the current and upcoming observational campaigns of which I am a part that will further expand our view of the low-mass galaxy population.