Dissecting the Circumgalactic Medium of Massive Quiescent Galaxies

Fakhri Zahedy (U Chicago)
Friday, September 28, 2018 - 12:15pm

Significant progress has been made in understanding the many 

aspects of galaxy evolution over the past two decades. However, what still 
eludes us is a self-consistent explanation of the diffuse gas surrounding 
galaxies, known as the circumgalactic medium (CGM). Particularly puzzling 
is the widespread presence of cool gas in the CGM of massive quiescent 
galaxies, 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 from 
COS-LRG, a systematic study of the CGM of massive quiescent galaxies 
at z~0.4 using the Cosmic Origins Spectrograph onboard the Hubble Space 
Telescope. I will illustrate what investigating the elemental abundances, 
abundance patterns, kinematics, and ionization states of the gas tells us 
about 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 of 
massive galaxies and their halo gas.
Talk Type: