Unveiling the role of environment on the growth of galaxies and dark-matter halos

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Galaxies have a complex relationship with surrounding gas. Cosmic-web filaments take on especially important roles for halo and galaxy growth: simulations indicate that around 40 percent of the Dark Matter in the Universe is found within filaments, and they act as conduits that feed Dark Matter and neutral, cold gas into halos and galaxies. The neutral cold gas, once accreted onto a galaxy, will almost always form stars, at which point it becomes easily detectable via starlight. However, although a key player in the formation and growth of galaxies, we know astoundingly little about the gas component of the cosmic web, before it reaches the vicinity of a galaxy.In this project, you will cross-correlate excess absorption in the spectra of distant quasars with filaments detected via the positions of galaxies, to understand the gas content of the cosmic web, far from the influence of dark matter halos. You will work with eBOSS and DESI data, which together provide the densest sample of lines of sight that pierce the low-redshift cosmic web. Your observational work will be complemented by work in cosmological hydrodynamical simulations