I am a fifth year Ph.D. candidate working with Alyson Brooks. I use cosmological simulations to study galaxies that are difficult to study with telescopes: the small, the dim, and the diffuse. All of the simulations that I use are run with N-body+SPH code Gasoline or its newer cousin, ChaNGa.
I investigate dwarf galaxies that are initially quenched by reionization, but which resume star formation at least 2 Gyr later. In our simulations, star formation is restarted in these galaxies when they are struck by a stream of gas, typically either thrown off during a nearby merger (as in the above gif) or simply hanging off of a neighboring galaxy. If the ram pressure exerted by the stream is within the right range, some of the gas in the hot halo of the dwarf is compressed onto its disk, forming neutral hydrogen (HI) and, eventually, stars. I am interested in how the gas within dwarf galaxies evolves and, in particular, the role that environment plays in these developments.
Low Surface Brightness Galaxies
A low surface brightness galaxy (LSB) is broadly defined as any galaxy with a central surface brightness dimmer than 22.5 mag/arcsec2. However, classical LSBs are also typically blue, metal-poor, gas-rich and possess either a disk-like or irregular morphology. Whether these characteristics are a product of the high spin dark matter halos they are proposed to inhabit, the underdense environments they have been observed to populate, or an entirely different set of factors is unknown. Also unexplained are the discrepancies between the cuspy dark matter halo density profile that a galaxy with low past and current star formation rates would be expected to possess and the cored profiles that LSB rotation curves are most consistent with. I am interested in using cosmological simulations to study the formation and evolution of these galaxies.
Ultra Diffuse Galaxies
As their name suggests, ultra diffuse galaxies (UDGs) are diffuse, having effective radii of at least 1.5 kpc. Like LSBs, they are also characterized by low central surface brightnesses -- dimmer than 24 mag/arcsec2. UDGs are primarily red in color and appear to be heavily dark matter dominated. Although originally discovered in clusters, they have also been observed in the field, which suggests that it is not purely the violence of the cluster environment that creates them. I am interested in using cosmological simulations to study the formation and evolution of these galaxies in the field.