Hydrogen and Metal Line Absorption Around Low-Redshift Galaxies in Cosmological Hydrodynamic Simulations

Understand

We study the physical conditions of the circum-galactic medium (CGM) around z=0.25 galaxies as traced by HI and metal line absorption, using cosmological hydrodynamic simulations that include galactic outflows.

• Using lines of sight targeted at impact parameters from 10 kpc to 1 Mpc around galaxies with halo masses from 10^11-10^13 M_solar, we study the physical conditions and their variation with impact parameter b and line-of-sight velocity delta v in the CGM as traced by HI, MgII, SiIV, CIV, OVI, and NeVIII absorbers.
• All ions show a strong excess of absorption near galaxies compared to random lines of sight.
• The excess continues beyond 1 Mpc, reflecting the correlation of metal absorption with large-scale structure.