Hierarchical Structure Formation and Chemical Evolution of Damped Ly alpha Systems

Abstract

We present a model for chemical evolution of damped Ly alpha systems considering production of metals by SNe II and infall associated with hierarchical structure formation. The growth of metallicity in these systems is a reflection of the competition between astration and infall. The apparent late turn-on of these systems is due to the late cut-off of infall. The wide range in [Fe/H] at a given redshift is explained by the range of the times for onset of star formation and the range of the times for infall cessation in different systems. The observed lower bound of [Fe/H] = -3 follows from the very rapid initial rise of [Fe/H] subsequent to onset of star formation. To reach [Fe/H] = -3 from a metal-free initial state requires only about 30 Myr so that the probability of observing lower [Fe/H] values is very small.

4 pages, 2 figures, to appear in ApJL

References in corpus (3)

• The Age-Metallicity Relation of the Universe in Neutral Gas: The First 100 Damped Lya Systems
• The C IV Mass Density of the Universe at Redshift 5
• Stellar Sources for Heavy r-Process Nuclei

Cited by in corpus (5)

• Damped Lyman alpha Systems
• Probing the ISM Near Star Forming Regions with GRB Afterglow Spectroscopy: Gas, Metals, and Dust
• Two populations of metal-free stars in the early Universe
• Damped Lyα Absorption Systems in Semi-Analytic Models with Multiphase Gas
• Hierarchical Structure Formation and Chemical Evolution of Galaxies