Fakhri Zahedy (U Chicago)
Friday, September 28, 2018 - 12:15pm
Significant progress has been made in understanding the manyaspects of galaxy evolution over the past two decades. However, what stilleludes us is a self-consistent explanation of the diffuse gas surroundinggalaxies, known as the circumgalactic medium (CGM). Particularly puzzlingis the widespread presence of cool gas in the CGM of massive quiescentgalaxies, contrary to expectation that the gaseous halo is predominantly hot.A detailed characterization of the gaseous halos of massive “red and dead”galaxies is necessary to solve this puzzle. I will highlight new results fromCOS-LRG, a systematic study of the CGM of massive quiescent galaxiesat z~0.4 using the Cosmic Origins Spectrograph onboard the Hubble SpaceTelescope. I will illustrate what investigating the elemental abundances,abundance patterns, kinematics, and ionization states of the gas tells usabout physical processes in the CGM of massive quiescent galaxies. Finally,I will discuss the implications of these findings on the origin and fate of the gas,and point to a future direction for our quest to understand the co-evolution ofmassive galaxies and their halo gas.