Abstract

Absorption and emission measurements reveal the existence of extended multiphase gas around galaxies in the local and high-redshift Universe. Due to the challenging nature of the observations, many questions remain open – how much gas is out there, what are its thermal properties, spatial distribution, and morphology? These are linked to the properties of gas accretion onto galaxies, star formation, and feedback processes, and are important for our understanding of galaxy evolution. I will present analytic phenomenological models for the circumgalactic medium (CGM) of the Milky Way and other L* galaxies in the low redshift universe. Our models allow for non-thermal support and heating by feedback, and describe the thermal and ionization state of the CGM . They reproduce a wide range of observations, from the warm/hot virialized phase to the cool, photoionized gas, and provide predictions for future UV, X-ray, and radio observations.