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Age-Metallicity Relation of the Universe in Neutral Gas: The First 100 Damped Lyα Systems

Prochaska, Jason X. and Gawiser, Eric and Wolfe, Arthur M. and Castro, Sandra and Djorgovski, S. G. (2003) Age-Metallicity Relation of the Universe in Neutral Gas: The First 100 Damped Lyα Systems. Astrophysical Journal, 595 (1). L9-L12. ISSN 0004-637X. doi:10.1086/378945.

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We discuss accurate metallicity measurements for 125 damped Lyα (DLA) systems at 0.5 < z < 5, including ≈50 new measurements from our recently published Echellette Spectrograph and Imager surveys. This data set is analyzed to determine the age-metallicity relation of neutral gas in the universe. Contrary to previous analyses, this sample shows statistically significant evolution in the cosmic mean metallicity. The best linear fit for metallicity evolution is -0.26 ± 0.07 dex per unit redshift. The DLA systems continue to maintain a floor in metallicity of ≈1/700 solar, independent of observational effects. This metallicity threshold limits the prevalence of primordial gas in high-redshift galaxies and stresses the correspondence between damped systems and star formation. Finally, we comment on an apparent "missing metals problem:" the mean metallicity of the damped systems is ≈10 times lower than the value expected from their inferred star formation history. This problem is evident in current theoretical treatments of galaxy formation and may indicate a serious flaw in our understanding of the interplay between star formation and metal enrichment.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Prochaska, Jason X.0000-0002-7738-6875
Djorgovski, S. G.0000-0002-0603-3087
Additional Information:© 2003 The American Astronomical Society. Received 2003 May 7; accepted 2003 August 8; published 2003 August 21. We acknowledge the Keck staff for their efforts in performing these observations. We thank M. Pettini for helpful comments and acknowledge collaborators S. Rao and D. Turnshek, who allowed us to present measurements prior to publication. E. G. is supported by NSF award AST 02-01667. A. M. W. is partially supported by NSF grant AST 00-71257. S. G. D. acknowledges partial support from the Ajax Foundation.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
NSF Astronomy and Astrophysics FellowshipAST 02-01667
NSFAST 00-71257
Ajax FoundationUNSPECIFIED
Subject Keywords:galaxies: abundances—galaxies: ISM—quasars: absorption lines
Issue or Number:1
Record Number:CaltechAUTHORS:20191002-144036689
Persistent URL:
Official Citation:Jason X. Prochaska et al 2003 ApJ 595 L9
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:99028
Deposited By: Tony Diaz
Deposited On:02 Oct 2019 21:52
Last Modified:16 Nov 2021 17:43

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