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Damped Lyα systems as probes of chemical evolution over cosmological timescales

Dessauges-Zavadsky, Miroslava

In: Proceedings of the International Astronomical Union, 2008, vol. 4, no. S255, p. 121-128

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    Title
    • Damped Lyα systems as probes of chemical evolution over cosmological timescales
    Author
    • Dessauges-Zavadsky, Miroslava. Geneva Observatory, University of Geneva, 51, Ch. des Maillettes, 1290 Sauverny, Switzerland email: miroslava.dessauges@unige.ch
    Document Type
    • Postprint
    Language
    • English
    Published in
    • Proceedings of the International Astronomical Union, 2008, vol. 4, no. S255, p. 121-128. Cambridge University Press
    Other Version
    OAI-PMH Identifier
    • oai:doc.rero.ch:291654
    Summary
    We review the current state of knowledge of damped Lyα systems (DLAs) selected in absorption on quasar sightlines. These objects are extremely useful to study the interstellar medium of high-redshift galaxies and the nucleosynthesis in the early Universe. The characteristics of this galaxy population has been investigated for years and slowly we are getting information on their puzzling nature. Imaging at z <1 shows that DLAs are associated with a mixing bag of galaxies with no especially large contribution from dwarf galaxies. Evidence for a mild evolution of the cosmic mean metallicity with time is observed. The star formation histories of these high-redshift galaxies begin to be accessible and indicate that DLAs tend to be young, gas-dominated galaxies with low star formation rates per unit area. Finally, indirect estimation of the DLA stellar masses from the mass-metallicity relations observed for emission-selected star-forming galaxies at z = 2−3 points to intermediate-mass galaxies with M* < 109 M