Werk, JessicaWilde, Matthew2022-09-232022-09-232022-09-232022Wilde_washington_0250E_24808.pdfhttp://hdl.handle.net/1773/49255Thesis (Ph.D.)--University of Washington, 2022The work presented in this dissertation provides the groundwork for understanding key unresolved questions in the study of galaxy evolution: the circumgalactic medium (CGM) and the role of environment. I present a new survey that has the power to drastically improve our understanding of the CGM and use it to estimate the size of the CGM as a function of galactic mass. In addition, a novel method to reconstruct the cosmic web using \textit{Physarum polycephalum} slime mold is presented and applied to the SDSS surveys. This cosmic web reconstruction was released publicly with SDSS DR17 and will allow exciting connections between galaxies and their environments to be illuminated, to distances greater than other previous catalogs.application/pdfen-USCC BYCGMCircumgalactic MediumData ScienceGalaxy EvolutionSlime MoldAstrophysicsAstronomyThesis