Misc,
The Effect of Star Formation on the Redshift Evolution of Interstellar Metals, Atomic and Molecular Gas in Galaxies
(2012)cite arxiv:1203.5280Comment: Submitted to MNRAS, 15 pages, 10 figures.
Abstract
We examine how the atomic and molecular gas components of galaxies evolve to
higher redshifts using the semi-analytic galaxy formation models of Fu et al.
(2010) in which we track the surface density profiles of gas in disks. We adopt
two different prescriptions based either on gas surface density and
metallicity, or on interstellar pressure, to compute the molecular fraction as
a function of radius in each disk. We demonstrate that the adopted star
formation law determines how the balance between gas, stars and metals changes
with time in the star-forming galaxy population, but does not influence the
total mass in stars formed into galaxies at redshifts below z~2.5. The redshift
evolution of the mass-metallicity relation places strong constraints on the
timescale over which cold gas is converted into stars in high redshift
galaxies, and favours models in which the star formation surface density scales
with the cold gas surface density in the same way at all cosmic epochs. Future
observations of the evolution of the average molecular-to-atomic gas ratio in
galaxies as a function of stellar mass and redshift will constrain models of
the atomic-to-molecular transition.
