MUFASA: Galaxy star formation, gas, and metal properties across cosmic
  time
  We examine galaxy star formation rates (SFRs), metallicities, and gas
contents predicted by the MUFASA cosmological hydrodynamic simulations, which
employ meshless hydrodynamics and novel feedback prescriptions that yield a
good match to observed galaxy stellar mass assembly. We combine 50, 25, and
12.5 Mpc/h boxes with a quarter billion particles each to show that MUFASA
broadly reproduces a wide range of relevant observations, including SFR and
specific SFR functions, the mass-metallicity relation, HI and H2 fractions, HI
(21 cm) and CO luminosity functions, and cosmic gas density evolution. There
are mild but significant discrepancies, such as too many high-SFR galaxies,
overly metal-rich and HI-poor galaxies at M*>10^{10} Mo, and sSFRs that are too
low at z~1-2. The HI mass function increases by x2 out to z~1 then steepens to
higher redshifts, while the CO luminosity function computed using the Narayanan
et al. conversion factor shows a rapid increase of CO-bright galaxies out to
z~2 in accord with data. Omega_HI and Omega_H2 both scale roughly as (1+z)^0.7
out to z~3, comparable to the rise in HI and H2 fractions. MUFASA galaxies with
high SFR at a given M* have lower metallicities and higher HI and H2 fractions,
following observed trends; we make quantitative predictions for how
fluctuations in the baryon cycle drive correlated scatter around galaxy scaling
relations. Most of these trends are well converged with numerical resolution.
These successes highlight MUFASA as a viable platform to study many facets of
cosmological galaxy evolution.
