Chemical Evolution of Spiral Galaxies from Redshift 4 to the Present

Abstract

We use our unified chemical and spectrophotometric evolutionary synthesis code to describe galaxies of various Hubble types. With stellar evolutionary tracks and element yields for 5 different metallicities we follow the spectrophotometric evolution of composite stellar populations and the chemical evolution of ISM abundances in a chemically consistent way, i.e., accounting for the increasing initial metallicities of successive generations of stars. Evolutionary galaxy models are required to give agreement with template nearby galaxies of various Hubble types in terms of SEDs, stellar absorption indices or HII region abundances, respectively. Within the framework of a given cosmological model the redshift evolution of ISM abundances and abundance ratios is compared to damped Lyman $α$ abundances. This provides information about the early star formation and nucleosynthesis history of the absorber galaxies and, at the same time, our models predict their spectral energy distributions. Optically identified DLA absorbers, with their spectral and chemical properties, provide, of course, the strongest constraints for the model parameters.