Chemical constraints on the star formation history in high redshift galaxies

Abstract

Abstract.It is now possible to study the chemical properties of distant galaxies through emission line diagnostics which have long been used in local H II regions. Initial results from a sample of compact, narrow emission line galaxies at z = 0.2 to z = 0.5 show a range of metallicities from metal-poor like the SMC to super solar. The oxygen abundances correlate strongly with optical luminosity just like local galaxies. This suggests that the chemical production and retention in individual galaxies is determined predominantly by local characteristics, such as the integrated star formation activity and the depth of the gravitational potential rather than the cosmic star formation history. The ratios of specific elements like nitrogen-to-oxygen can constrain the evolutionary descendants of hi-z galaxies.