Introduction to Galactic Chemical Evolution

TL;DR

This paper introduces the principles and models of galactic chemical evolution, discussing analytical and numerical approaches, and compares predictions with observational data to understand element formation and distribution in galaxies.

Contribution

It provides a comprehensive overview of modeling techniques and critical analysis of assumptions in galactic chemical evolution studies.

Findings

Analytical models offer simplified insights but have limitations.

Numerical models can track element abundances over time.

Comparisons with observations constrain stellar nucleosynthesis and galaxy formation theories.

Abstract

In this lecture I will introduce the concept of galactic chemical evolution, namely the study of how and where the chemical elements formed and how they were distributed in the stars and gas in galaxies. The main ingredients to build models of galactic chemical evolution will be described. They include: initial conditions, star formation history, stellar nucleosynthesis and gas flows in and out of galaxies. Then some simple analytical models and their solutions will be discussed together with the main criticisms associated to them. The yield per stellar generation will be defined and the hypothesis of instantaneous recycling approximation will be critically discussed. Detailed numerical models of chemical evolution of galaxies of different morphological type, able to follow the time evolution of the abundances of single elements, will be discussed and their predictions will be compared to observational data. The comparisons will include stellar abundances as well as interstellar medium ones, measured in galaxies. I will show how, from these comparisons, one can derive important constraints on stellar nucleosynthesis and galaxy formation mechanisms. Most of the concepts described in this lecture can be found in the monograph by Matteucci (2012).