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Statistical Properties of DLAs and sub-DLAs

Celine Peroux·Mike J. Irwin·Richard G. McMahon·Lisa J. Storrie-Lombardi
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Abstract

Quasar absorbers provide a powerful observational tool with which to probe both galaxies and the intergalactic medium up to high redshift. We present a study of the evolution of the column density distribution, f(N,z), and total neutral hydrogen mass in high-column density quasar absorbers using data from a recent high-redshift survey for damped Lyman-alpha (DLA) and Lyman limit system (LLS) absorbers. Whilst in the redshift range 2 to 3.5, ~90% of the neutral HI mass is in DLAs, we find that at z>3.5 this fraction drops to only 55% and that the remaining 'missing' mass fraction of the neutral gas lies in sub-DLAs with N(HI) 10^{19} - 2 * 10^{20} cm^{-2}.

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Celine Peroux, Mike J. Irwin, Richard G. McMahon, Lisa J. Storrie-Lombardi. 2001-07-06. Statistical Properties of DLAs and sub-DLAs. https://arxiv.org/abs/astro-ph/0107125

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