Galactic chemical evolution - the observational side

Abstract

In this review I first outline some interesting ideas in chemical evolution, necessary for understanding the evolution of galaxies from measured elemental abundance ratios. I then discuss abundance results from studies of stars in Local Group dwarf galaxies and the globular cluster Omega Cen. Finally, I present a qualitative scenario of prolonged chemical evolution in a leaky box that can explain the observed abundance ratios trends in these dwarf systems. Unfortunately, space limitations prevent a comprehensive discussion of the vast field of observational chemical evolution, so I have limited this paper to a few interesting subtopics. I have completely omitted the Galactic bulge; this may be as well, because there is some disagreement over the measured abundance ratios, except for [O/Fe] which follows the thick disk trend.