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Precious Metals in SDSS Quasar Spectra. I. Tracking the Evolution of Strong, 1.5 < z < 4.5 C IV Absorbers with Thousands of Systems

Cooksey, Kathy L. and Kao, Melodie M. and Simcoe, Robert A. and O'Meara, John M. and Prochaska, J. Xavier (2013) Precious Metals in SDSS Quasar Spectra. I. Tracking the Evolution of Strong, 1.5 < z < 4.5 C IV Absorbers with Thousands of Systems. Astrophysical Journal, 763 (1). Art. No. 37. ISSN 0004-637X.

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We have vastly increased the C iv statistics at intermediate redshift by surveying the thousands of quasars in the Sloan Digital Sky Survey (SDSS) Data-Release 7.We visually verified over 16,000 Civ systems with 1.46 < z < 4.55—a sample size that renders Poisson error negligible. Detailed Monte Carlo simulations show that we are approximately 50% complete down to rest equivalent widths W_r ≈ 0.6Å. We analyzed the sample as a whole and in 10 small redshift bins with approximately 1500 doublets each. The equivalent width frequency distributions f (W_r) were well modeled by an exponential, with little evolution in shape. In contrast with previous studies that modeled the frequency distribution as a single power law, the fitted exponential gives a finite mass density for the Civ ions. The comoving line density dN_(Civ)/dX evolved smoothly with redshift, increasing by a factor of 2.37 ± 0.09 from z = 4.55–1.96, then plateauing at dN_(Civ)/dX ≈ 0.34 for z = 1.96–1.46. Comparing our SDSS sample with z < 1 (ultraviolet) and z > 5 (infrared) surveys, we see an approximately 10-fold increase in dN_(Civ)/dX over z ≈ 6 → 0, for W_r ≥� 0.6Å. This suggests a monotonic and significant increase in the enrichment of gas outside galaxies over the 12 Gyr lifetime of the universe.

Item Type:Article
Related URLs:
URLURL TypeDescription
Kao, Melodie M.0000-0001-5125-1414
Simcoe, Robert A.0000-0003-3769-9559
O'Meara, John M.0000-0002-7893-1054
Prochaska, J. Xavier0000-0002-7738-6875
Additional Information:© 2013 American Astronomical Society. Received 2012 April 11; accepted 2012 November 21; published 2013 January 4. We thank J. Harker, D. Ogden, J. Pritchard, and P. Creasey for their programming help and P. Jonsson for productive discussions regarding statistics and programming. We gratefully acknowledge the vital role of the Adam J. Burgasser Endowed Chair. The current study was funded largely by the National Science Foundation Astronomy & Astrophysics Postdoctoral Fellowship (AST-1003139) and in part by the MIT Department of Physics and the Alfred P. Sloan Foundation Research Fellowship. Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England. The SDSS Web site is The SDSS is managed by the Astrophysical Research Consortium for the Participating Institutions. The Participating Institutions are the American Museum of Natural History, Astrophysical Institute Potsdam, University of Basel, University of Cambridge, Case Western Reserve University, University of Chicago, Drexel University, Fermilab, the Institute for Advanced Study, the Japan Participation Group, Johns Hopkins University, the Joint Institute for Nuclear Astrophysics, the Kavli Institute for Particle Astrophysics and Cosmology, the Korean Scientist Group, the Chinese Academy of Sciences (LAMOST), Los Alamos National Laboratory, the Max-Planck- Institute for Astronomy (MPIA), the Max-Planck-Institute for Astrophysics (MPA), New Mexico State University, Ohio State University, University of Pittsburgh, University of Portsmouth, Princeton University, the United States Naval Observatory, and the University of Washington. Facility: Sloan
Funding AgencyGrant Number
NSF Astronomy and Astrophysics FellowshipAST-1003139
Massachusetts Institute of Technology (MIT)UNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
Subject Keywords:galaxies: halos; intergalactic medium; quasars: absorption lines; techniques: spectroscopic
Issue or Number:1
Record Number:CaltechAUTHORS:20130215-134548329
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Official Citation:Precious Metals in SDSS Quasar Spectra. I. Tracking the Evolution of Strong, 1.5 < z < 4.5 C IV Absorbers with Thousands of Systems Kathy L. Cooksey et al. 2013 ApJ 763 37
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:36962
Deposited By: Ruth Sustaita
Deposited On:15 Feb 2013 22:10
Last Modified:09 Mar 2020 13:19

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