A Homogeneous Sample of Sub-DLAs I: Construction of the Sample and Chemical Abundance Measurements

Abstract

In this first paper of a series, we report on the use of quasar spectra obtained with the UVES high resolution spectrograph and available through the ESO VLT archive to build the first sample of sub-DLA systems, absorbers with HI column densities > 10^{19} cm^{-2} but lower than the classical definition of damped Ly-alpha systems (DLAs) 2x10^{20} cm^{-2}. A systematic investigation of the properties of these systems and a comparison with those of the DLAs (Paper II of this series; Peroux et al. 2003b) is expected to provide new clues on the association of high column density absorbers with galaxies and on the overall evolution of the neutral hydrogen gas mass and metal content in the Universe. In the spectra of 22 quasars which were found suitable for a sub-DLA search, we identified 12 sub-DLAs and 1 borderline case between the DLA and sub-DLA systems in the redshift interval z = 1.8-4.3. We measured the column densities of HI and up to 16 ions of low-, intermediate- and high-ionization. We further investigated the significance of the ionization corrections in the determination of the chemical abundances from the low-ionization ions in the sub-DLA HI column density range. Using the predictions of different ion ratios as a function of the ionization parameter computed with the CLOUDY software package, we have estimated that with the exception of one case, the ionization corrections to the abundances of 9 systems for which we were able to constrain the ionization parameter, are lower than 0.2 dex for all of the elements except AlII and ZnII down to HI column densities of log N(HI) = 19.3 cm^{-2}. We finally present the first sub-DLA chemical abundance database which contains the abundance measurements of 11 different elements (O, C, Si, N, S, Mg, Al, Fe, Ni, Zn, and Cr).

35 pages, 43 figures, Accepted for publication in MNRAS (high-resolution figures available on request from the authors or in the journal)

References in corpus (44)

• Radiative Transfer in a Clumpy Universe: II. The Utraviolet Extragalactic Background
• Radiative Transfer in a Clumpy Universe: III. The Nature of Cosmological Ionizing Sources
• Heavy element abundances in blue compact galaxies
• Abundances at High Redshifts: the Chemical Enrichment History of Damped Lyman-alpha Galaxies
• Damped Lyman alpha absorbers at high redshift -- large disks or galactic building blocks?
• Cosmic Histories of Stars, Gas, Heavy Elements, and Dust
• Cosmic Chemical Evolution
• Surveys for z > 3 Damped Lyman-alpha Absorption Systems
• Metal Abundances at z < 1.5: Fresh Clues to the Chemical Enrichment History of Damped Lyman alpha Systems
• The UCSD HIRES/KeckI Damped Lya Abundance Database: II. The Implications
• Chemical Abundances of the Damped Lya Systems at z>1.5
• The Abundances of Nitrogen and Oxygen in Damped Lyman Alpha Systems
• Protogalactic Disk Models of Damped Lya Kinematics
• Molecular hydrogen, deuterium and metal abundances in the damped Ly-alpha system at z = 3.025 toward QSO 0347-3819
• The UCSD HIRES/KeckI Damped Lya Abundance Database: I. The Data
• Ionization Properties and Elemental Abundances in Damped Ly alpha Systems
• The Lyman-Alpha Forest at 1.5 < z < 4
• A Homogeneous Sample of Sub-DLAs II: Statistical, Kinematic and Chemical Properties
• Metallicity Evolution in the Early Universe
• Approaching Reionization: The Evolution of the Lyman Alpha Forest from Redshifts Four to Six
• A Keck HIRES Investigation of the Metal Abundances and Kinematics of Three Damped Lya Systems Toward Q2206-199
• Absorption Systems in the Spectra of 66 z > 4 Quasars
• A Keck HIRES Investigation of the Metal Abundances and Kinematics of the z=2.46 Damped Lya System Toward Q0201+365
• First Comparison of Ionization and Metallicity in Two Lines of Sight Toward HE 1104-1805 AB at z=1.66
• Abundances and Physical Conditions in the Warm Neutral Medium Towards mu Columbae
• NICMOS imaging search for damped Lya galaxies
• Chemical evolution and nature of Damped Lyman-Alpha systems
• Ionized Gas in Damped Lyman-alpha Systems and Its Effects on Elemental Abundance Studies
• Metal abundances and ionization conditions in a possibly dust-free damped Ly-alpha system at z=2.3
• Chemical Evolution of Damped Ly alpha galaxies: The [S/Zn] abundance ratio at redshift z > 2
• On the origin of Damped Lyman-alpha systems: a case for LSB galaxies?
• The UCSD HIRES/KeckI Damped Lya Abundance Database III. An Empirical Study of Photoionization in the Damped Lya System Toward GB1759+7539
• The evolution of the physical state of the IGM
• Galactic Chemical Abundances at z>3 I: First Results from the Echellette Spectrograph and Imager
• UVES observations of a damped Ly-alpha system at z_abs = 4.466 towards the quasar APM BR J0307-4945
• Molecular signals from primordial clouds at high redshift
• Zinc as a tracer of metallicity evolution of Damped Lyman alpha systems
• On ionization effects and abundance ratios in damped Lyman alpha systems
• New detections of Mn, Ti and Mg in damped Ly-alpha systems: Toward reconciling the dust/nucleosynthesis degeneracy
• The First Detection of Cobalt in a Damped Lyman Alpha System
• A new measurement of zinc metallicity in a DLA at z=3.35
• Inhomogeneous metal enrichment at z \sim 1.9: the Lyman limit systems in the spectrum of the HDF-S quasar
• Metal abundances and kinematics of quasar absorbers - II. Absorption systems toward Q0347-3819 and APM BR J0307-4945
• The Second APM UKST Colour Survey for z>4 Quasars

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