| Abstract: | Gas in galaxy-scale dark matter halos, known as the circumgalactic medium (CGM), is both the source of fuel for star formation in the galaxy and the destination of galaxy outflows. The CGM is thus expected to play a fundamental role in galaxy evolution. I will present a systematic analysis of the CGM based on a combination of an analytic cooling flow treatment, controlled numerical experiments, and fully cosmological simulations. I will show that our analysis allows us to understand, and make predictions for, multiple transitions experienced by galaxies as they evolve in mass and redshift, including the emergence of galactic disks, the stabilization of galactic star formation rates, and the decline in star-formation driven galactic winds. |