MAGICC haloes: confronting simulations with observations of the
  circumgalactic medium at z=0
  We explore the circumgalactic medium (CGM) of two simulated star-forming
galaxies with luminosities L ~ 0.1 and 1 L* generated using the smooth particle
hydrodynamic code GASOLINE. These simulations are part of the Making Galaxies
In a Cosmological Context (MAGICC) program in which the stellar feedback is
tuned to match the stellar mass-halo mass relationship. For comparison, each
galaxy was also simulated using a 'lower feedback' (LF) model which has
strength comparable to other implementations in the literature. The 'MAGICC
feedback' (MF) model has a higher incidence of massive stars and an
approximately two times higher energy input per supernova. Apart from the
low-mass halo using LF, each galaxy exhibits a metal-enriched CGM that extends
to approximately the virial radius. A significant fraction of this gas has been
heated in supernova explosions in the disc and subsequently ejected into the
CGM where it is predicted to give rise to substantial O VI absorption. The
simulations do not yet address the question of what happens to the O VI when
the galaxies stop forming stars. Our models also predict a reservoir of cool H
I clouds that show strong Ly\alpha absorption to several hundred kpc. Comparing
these models to recent surveys with the Hubble Space Telescope, we find that
only the MF models have sufficient O VI and H I gas in the CGM to reproduce the
observed distributions. In separate analyses, these same MF models also show
better agreement with other galaxy observables (e.g. rotation curves, surface
brightness profiles and H I gas distribution). We infer that the CGM is the
dominant reservoir of baryons for galaxy haloes.
