[Astronomy seminar] Astronomy seminar this Friday

[Astronomy seminar announcements]

All,

The astronomy seminar this Friday will be

*** Friday 8 of Sept from 10:30 to 11:30 at FC61 ***

Welcome.


Title:  The circumgalactic gas and metals around star forming and 
elliptical galaxies

Speaker: Sijing Shen, Institute of Theoretical Astrophysics, Oslo

Abstract:

Understanding the baryon cycle in galaxies, i.e., how gas is accreted 
onto galaxies, consumed in star formation, and ejected back to the 
environment is crucial to understand galaxy formation and evolution. 
Studies of the distribution, kinematics and evolution of the gas and 
metals in the circumgalactic medium (CGM) provide clues to understanding 
this baryon cycle.  In this talk, I will briefly review recent progress 
on observational and theoretical studies on the CGM. I will then present 
new results on the circumgalactic gas and metals around massive 
star-forming and elliptical galaxies at z~3-0 from two suites of 
“zoom-in” cosmological hydrodynamic simulations, and detailed 
comparisons with observed Lyman alpha (Lya) and metal absorption data 
(e.g. Mg II, Si II, Si III, C II, C III, CIV and OVI) in particular from 
the COS-Halos Survey. We found that simulations generally reproduce the 
distributions of of neutron hydrogen and high-ionisation metal ions 
(such as O VI), but significantly underestimate the low-ionisation metal 
species. I will explore possible reasons for the mis-match and discuss 
the correlation between the cold, enriched gas probed by the low ions 
and the warm-hot gas probed by O VI. I will also discuss the impact of 
feedback from supernova and the active galactic nuclei (AGN).