The impact of galactic feedback on the circumgalactic medium


Type
Article
Change log
Authors
Suresh, J 
Bird, S 
Vogelsberger, M 
Genel, S 
Torrey, P 
Abstract

Galactic feedback strongly affects the way galactic environments are enriched. We examine this connection by performing a suite of cosmological hydrodynamic simulations, exploring a range of parameters based on the galaxy formation model developed in Vogelsberger et al. 2013 (henceforth V13). We examine the effects of AGN feedback, wind mass loading, wind specific energy, and wind metal-loading on the properties of the circumgalactic medium (CGM) of galaxies with Mhalo>1011M. Note that while the V13 model was tuned to match observations including the stellar mass function, no explicit tuning was done for the CGM. The wind energy per unit outflow mass has the most significant effect on the CGM enrichment. High energy winds launch metals far beyond the virial radius. AGN feedback also has a significant effect, but only at z<3. We compare to high redshift HI and CIV observations. All our simulations produce the observed number of Damped Lyman-α Absorbers. At lower column density, several of our simulations produce enough Lyman Limit Systems (LLS) 100 kpc from the galaxy, but in all cases the LLS abundance falls off with distance faster than observations, with too few LLS at 200 kpc. Further, in all models the CIV abundance drops off too sharply with distance, with too little CIV 100-200 kpc from the galaxy. Higher energy wind models produce more extended CIV but also produce less stars, in tension with star-formation rate density observations. This highlights the fact that circumgalactic observations are a strong constraint on galactic feedback models.

Description
Keywords
galaxies: formation, intergalactic medium
Journal Title
Monthly Notices of the Royal Astronomical Society
Conference Name
Journal ISSN
0035-8711
1365-2966
Volume Title
448
Publisher
Oxford University Press (OUP)
Sponsorship
Science and Technology Facilities Council (ST/L000725/1)