The Evolution of Galaxies on Cosmological Timescales

Abstract

I discuss the chemical and spectrophotometric evolution of galaxies over cosmological timescales and present a first attempt to treat both aspects in a chemically consistent way. In our evolutionary synthesis approach, we account for the increasing metallicity of successive generations of stars and use sets of stellar evolutionary tracks, stellar yields, spectra, etc. for various metallicities. This gives a more realistic description of nearby galaxies, which are observed to have broad stellar metalllicty distributions, as well as of young galaxies at high redshift. Selected results are presented for the chemo-cosmological evolution of galaxies as compared to QSO absorption line observations and for the spectrophotometric evolution of galaxies to very high redshifts. On cosmological timescales, intercations are important drivers of galaxy evolution. Neglecting dynamical aspects we study the effects of interaction-induced starbursts on the spectrophotometric and chemical evolution of galaxies and briefly discuss the formation of star clusters and Tidal Dwarf Galaxies in this context.