The Massive, Multiphase Circumgalactic Medium in High Definition

The environments extending hundreds of kiloparsecs from bright galaxies are now well-known to contain massive amounts of metal-enriched gas that spans several orders of magnitude in temperature (from ~10^4-10^7 K). Galaxy formation theory suggests that this material -- the circumgalactic medium (CGM) -- is destined to become the fuel that feeds star formation in these systems. Because of its extremely low density, however, it has proven very challenging to constrain the detailed spatial structure and distribution of this gas, and in turn to measure the rates of mass and energy exchange between the CGM and central galaxies. I will describe recent observational and theoretical advancements that provide new insights into the spatial distribution of the cool (~10^4 K) and warm (~10^5 K) phases of the CGM, and which suggest that the cool phase persists in structures as small as <100 Msun. The existence of such small-scale CGM structure poses a major challenge for computational models of galaxy formation, and yet must be understood to develop a complete picture of the cycling of material between galaxies and their surroundings.

Biography: Kate Rubin is an Associate Professor of Astronomy at San Diego State University. She completed her PhD in Astronomy in 2010 at UC Santa Cruz, and spent six years working as a postdoctoral fellow at the MPIA in Heidelberg, Germany and at the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA before moving San Diego in Fall 2016. She studies the movement of gas into and out of galaxies and the effects of this gas cycle on galaxy evolution. Her areas of expertise include extragalactic astronomy, galaxy formation and evolution, galactic winds and feedback, the circumgalactic medium, and QSO absorption line spectroscopy. (Credit: https://astronomy.sdsu.edu/people/kate-rubin/ and https://krubin.sdsu.edu/)