Galaxy Metallicities, Masses and Outflows at Redshifts 1 ≲Z≲ 3: An Observational Perspective

Abstract

I review the most widely used methods of determining chemical abundances in galaxies at 1≲ z ≲ 3, including emission and absorption line techniques (including a brief discussion of Damped Lyman Alpha systems). Most star-forming galaxies at these redshifts show significant enrichment, with ~1/3 solar to ~solar metallicities. They are overluminous for their metallicities compared to local galaxies, and the mass-metallicity relation at z ~ 2 is offset to lower metallicities compared to the local relation. Metals are also seen in the IGM at these redshifts, most likely from galactic-scale outflows in the galaxies themselves.