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Colloquium: In search of near-pristine gas at intermediate redshifts

Submitter: Max Pettini (University of Cambridge, UK)
Description: I will describe our recent searches for the most metal-poor damped Lyman alpha systems at redshifts between z = 2 and 4.
The improved statistics afforded by the Sloan Digital Sky Survey have led to the identification of moderately large samples of DLAs with metallicities of only 1/100 - 1/1000 of solar. High resolution spectroscopy of these QSO absorbers has clarified a number of lingering issues concerning stellar nucleosynthesis in the metal-poor regime, has revealed the existence of DLA analogues to the so-called ``Carbon-Enhanced Metal-Poor'' Stars in the halo of the Milky Way, and is providing some of the most precise measures of the primordial abundance of Deuterium.
Copyright: M. Pettini
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