UV Diagnostics of the Interaction between Starburst Galaxies and the Intergalactic Medium

Both galaxies and the intergalactic medium evolve dramatically between $z \approx 2$ and the present. These changes are coupled via galactic winds, cloud accretion, and ionizing radiation. Measurements of these interactions are critical for building a physical understanding of galaxy assembly. This paper reviews the role of starburst galaxies in heating, enriching, and ionizing the intergalactic medium. The strategies used to address these problems rely heavily on access to the rest-frame ultraviolet (UV) spectrum. Rather modest gains in UV sensitivity are shown to produce enormous gains in our ability to follow the very low-density gas dispersed by galactic winds and galaxy interactions. This leverage results from the sensitivity of absorption lines to low ionic columns and the very steep rise in the areal density of quasars toward fainter magnitudes.