Special Physics Colloquium

Joint surveys of galaxy evolution and fuel supplies over 10 billion years ofcosmic history

In a modern cosmological context, galaxy formation and evolution is understood as a self-regulating process in which star formation is fueled by the accretion ofgas from intergalactic space into the gravitational potential wells of darkmatter halos. After accretion, the gas cools and condenses to form stars. The most massive of these stars then explode as supernovae and inject energy, momentum, and heavy elements back into the surrounding gas to slow or even halt further gas cooling. The distribution, physical state, and chemical enrichment levels of the low density gas around and between galaxies therefore represents a key laboratory for testing our understanding of the physical processes thatgovern galaxy evolution. Except in rare and extreme environments, this gas is too diffuse to be detectable in emission with current facilities, but it can be directly observed through sensitive ultraviolet absorption spectroscopy taking advantage of bright background objects identified by cosmological surveys and followed-up with both ground- and space-based telescopes. I will present a series of surveys combining galaxies observed in emission and the surroundinggas observed in absorption that provide key insights into galaxy evolution inthe low and intermediate redshift Universe. When combined with on-goingtargeted observations and imminent cosmological experiments such as DESI and PFS, combined emission and absorption surveys will enable unprecedented, longitudinal studies of both galaxy evolution and the gas supplies that fuel them over 10 billion years of cosmic history.