Abstract

The circumgalactic medium (CGM) houses large-scale gaseous flows as well as a reservoir of material that can be used for future star formation. For galaxies to continue forming stars, they must accrete material that passes through the CGM in the form of inflows (recycling material or gas from the intergalactic medium, IGM) while also contending with outflows (winds escaping the galaxy disk). Here I present two projects that study the CGM of galaxies at z < 1, investigating whether the CGM properties correlate with the galaxy properties using absorbers known as partial Lyman limit systems (pLLSs) and Lyman limit systems (LLSs) with 16.0 ”Ü logNHI < 19.0 [cm-2]. Using a sample of blindly-selected pLLSs that span a broad range (0.1ØC54% solar) in metallicity, I utilize IFU observations to identify and characterize the host galaxies of these absorbers to determine the types of environments that house absorbers of different metallicities. In my second project, I observationally test model predictions for cold-mode and hot-mode accretion into galaxy halos by determining the cool HI gas content in the halos of luminous red galaxies (LRGs, logM”ļ > 11 M”Ń) at z ~ 0.5 and the metallicity of the absorbers we detect. My findings show the CGM metallicity does not correlate with most of the host galaxy properties, with the exception of stellar mass. There is no mass where we do not find cool gas in the inner CGM of galaxy halos, and low-metallicity absorbers are found in halos of all masses. However, the majority of these low-metallicity absorbers are most likely associated with filaments instead of galaxy halos at z < 1. With these two surveys, we see that to understand the interplay between the CGM and the galaxy, observations of both are necessary.