A simple physical model for young galaxies in the early Universe

We present a simple physical model featuring an evolutionary link between Lyα emitting (LAE), Lyman break (LBG), sub-millimeter bright (SMB), and passively evolving galaxies, in the framework of the approach by Granato et al. (Astrophys. J. 600:580, 2004), according to which the evolution of massive galaxies is tied to the growth of the supermassive black holes at their centers. A key role in determining the properties of high-z galaxies is played by dust absorption. We model its evolution adopting a power-law relationship between UV extinction, star formation rate and metallicity, whose parameters are determined from a fit to the luminosity-reddening correlation for Lyman Break Galaxies, found by Shapley et al. (Astrophys. J. 562:95, 2001). The model yields quantitative relations between luminosities and basic physical quantities such as stellar and halo masses, star formation rates, galactic ages, metal abundances and dust extinction. It reproduces the luminosity functions (LFs) of LBGs and of LAEs at different redshifts, in the framework of the scenario that was previously shown to account for the wealth of observational data on SMB and passively evolving galaxies, as well as on high redshift quasars.