Brainerd, Tereasa G.McDonough, Bryanne2025-09-052025-09-052025https://hdl.handle.net/2144/511612025Due to the large time scales over which galaxy- and group-scale changes take place, as well as the invisible nature of dark matter, many challenges remain in the study of galaxy formation and evolution in observations. I use mock galaxies from the TNG100 simulation to investigate the relationship between satellite galaxies and the dark matter that surrounds their central, “host” galaxies, as well as the star formation properties and histories of central and satellite galaxies. TNG100 is a state-of-the-art magnetohydrodynamical simulation that incorporates the best accepted model of structure formation: Lambda Cold Dark Matter. First, I investigate satellite galaxies as possible luminous tracers of their hosts’ dark matter halos. From this, I find that there is no observable subset of satellites with a radial number density profile that traces the underlying dark matter distribution well, including the subset of satellites that have resided within their hosts’ halos for the longest times. Next, I demonstrate that TNG100 reproduces the resolved star-forming main sequence (rSFMS) of observed galaxies on kiloparsec-scales. This is an important test of the physical models used in the simulation. I also find that choices made when projecting particles onto 2D grids (i.e., to obtain maps of surface mass density and star formation rate) can affect the resultant rSFMS when it is fit with ordinary least squares. Further, I use the 2D particle grids to study how quenching of star formation proceeds in central vs. satellite galaxies. From this, I gain insight into where star formation is occurring in TNG100 galaxies, and find that the spatial distribution of star formation is in qualitative agreement with observations. Lastly, I assess how intrinsic and environmental factors influence the spatially resolved distribution of star formation in TNG100 galaxies. In agreement with observations, I find that quenching of massive galaxies in these simulations is primarily driven by feedback energy imparted by their central supermassive black holes. For low-mass galaxies, quenching can also be driven by environmental processes (e.g., galaxy-galaxy interactions), and low-mass satellites are susceptible to quenching via stochastic processes such as ram pressure stripping within their hosts’ halos.en-USAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/AstrophysicsGalaxy evolutionSatellite galaxiesStar formationThesis/Dissertation2025-09-050000-0001-6928-4345