Chemical Evolution of Galaxies and the Relevance of Gas Processes

Abstract

Since stellar populations enhance particular element abundances according to the yields and lifetimes of the stellar progenitors, the chemical evolution of galaxies serves as one of the key tools that allows the tracing of galaxy evolution. In order to deduce the evolution of separate galactic regions one has to account for the dynamics of the interstellar medium, because distant regions can interact by means of large-scale dynamics. To be able to interpret the distributions and ratios of the characteristic elements and their relation to e.g. the galactic gas content, an understanding of the dynamical effects combined with small-scale transitions between the gas phases by evaporation and condensation is essential. In this paper, we address various complex signatures of chemical evolution and present in particular two problems of abundance distributions in different types of galaxies: the discrepancies of metallicity distributions and effective yields in the different regions of our Milky Way and the N/O abundance ratio in dwarf galaxies. These can be solved properly, if the chemodynamical prescription is applied to simulations of galaxy evolution.