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The Vlt-Uves Survey For Molecular Hydrogen In High-Redshift Damped Lyman Α Systems: Physical Conditions In The Neutral Gas, Raghunathan Srianand, Patrick Petitjean, Cédric Ledoux, Gary J. Ferland, Gargi Shaw

Physics and Astronomy Faculty Publications

We study the physical conditions in damped Lyman α systems (DLAs), using a sample of 33 systems towards 26 quasi-stellar objects (QSOs) acquired for a recently completed survey of H₂ by Ledoux, Petitjean & Srianand. We use the column densities of H₂ in different rotational levels, together with those of C I, C I*, C I**, C II* and singly ionized atomic species to discuss the kinetic temperature, the density of hydrogen and the electronic density in the gas together with the ambient ultraviolet (UV) radiation field. Detailed comparisons are made between the observed properties in DLAs, the …