An empirical model for the star formation history in dark matter haloes

Abstract

We develop an empirical approach to infer the star formation rate in dark matter haloes from the galaxy stellar mass function (SMF) at different redshifts and the local cluster galaxy luminosity function (CGLF), which has a steeper faint end relative to the SMF of local galaxies. As satellites are typically old galaxies which have been accreted earlier, this feature can cast important constraint on the formation of low-mass galaxies at high redshift. The evolution of the SMFs suggests the star formation in high-mass haloes (>1012 h-1M⊙) has to be boosted at high redshift beyond what is expected from a simple scaling of the dynamical time. The faint end of the CGLF implies a characteristic redshift zc ≈ 2 above which the star formation rate in low-mass haloes with masses <1011 h-1M⊙ must be enhanced relative to that at lower z. This is not directly expected from the standard stellar feedback models. Also, this enhancement leads to some interesting predictions, for instance, a significant old stellar population in present-day dwarf galaxies with M* ≤108 h-2M⊙ and steep slopes of high-redshift stellar mass and star formation rate functions. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.