2001/11/30 by P. Molaro, Paolo Molaro, Molaro, Paolo
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #Astrophysics and Star Formation Studies #FOS: Physical sciences #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0111592
to appear in the Proceedings of the XVII IAP Colloquium "Gaseous Matter in Galaxies and Intergalactic Space
arxiv created 2001/11/30 · openalex publication_date 2001/11/30 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Neutral hydrogen clouds with high column density detected towards distant quasars are unique probes of elemental nucleosynthesis and chemical evolution in the low metallicity regime. They provide measurements for several elements at very early times which are unfeasible in other astrophysical environments. Comparison between refractory and non-refractory elements provides evidence for the presence of dust, and the recently measured Ar probes photoionization. A prominent characteristic is the dominance of a solar abundance pattern, which is somewhat unexpected at low metallicities. It is argued that this property and Nitrogen observations can be used to constrain the age of the Damped Lyalpha systems and the epoch of star formation.