The Cosmological Evolution of Quasar Damped Lyman-Alpha Systems

2000/09/06 by Sandhya M. Rao, Sandhya Rao, Rao, Sandhya
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #FOS: Physical sciences #Scientific Research and Discoveries #astro-ph

paper · pdf · doi:10.48550/arxiv.astro-ph/0009098

To appear in "Gas and Galaxy Evolution", ASP Conference Series, eds. Hibbard, Rupen, and van Gorkum. 4 pages, 5 encapsulated postscript figures. newpasp.sty included

arxiv created 2000/09/06 · openalex publication_date 2000/09/06 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We present results from an efficient, non-traditional survey to discover damped Lyman-alpha (DLA) absorption-line systems with neutral hydrogen column densities N(HI)>2x10²⁰ atoms cm^-2 and redshifts z<1.65. Contrary to previous studies at higher redshift that showed a decrease in the cosmological mass density of neutral gas in DLA absorbers, Omega_DLA, with time, our results indicate that Omega_DLA is consistent with remaining constant from redshifts z ≈ 4 to z ≈ 0.5. There is no evidence that Omega_DLA is approaching the value at z=0. Other interesting results from the survey are also presented.

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