Greg Stinson, Chris Brook, J. Xavier Prochaska, Joe Hennawi, Andrew Pontzen, Sijing Shen, James Wadsley, Hugh Couchman, Tom Quinn, Andrea V. Macciò, Brad K. Gibson
We explore the circumgalactic medium (CGM) of two simulated star-forming
galaxies with luminosities $L \approx 0.1$ and $1 L^\star$ generated using the
smooth particle hydrodynamic code {\sc GASOLINE}. For each galaxy, we have
implemented two prescriptions for supernovae feedback: a "low feedback" (LF)
model which has strength comparable to other implementations in the literature
and a "high feedback" (HF) model that has a higher incidence of massive stars
and an $\approx 2\times$ higher energy input per supernova. Aside from the the
low mass halo using LF, each galaxy exhibits a metal-enriched CGM that extends
to approximately the virial radius. A significant portion of this gas has been
shock-heated to $T \sim 10^{5.5}\,$K and is predicted to give rise to
substantial \iovi\ absorption. These models also predict a reservoir of cool
\ihi\ clouds that show strong \lya\ absorption to several hundred kpc.
Comparing these models to recent surveys with the {\it Hubble Space Telescope},
we find that only the HF models have sufficient \iovi\ and \ihi\ gas in the CGM
to reproduce the observed distributions. In separate analysis, these same HF
models also offer better agreement to other galaxy observables (e.g.\ the
stellar mass-halo mass relation). We infer that the CGM holds the dominant
reservoir of baroyns for galaxy halos.
View original:
http://arxiv.org/abs/1112.1698
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