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Paper: Neutral Gas and Metals from z = 4 to z = 0.5
Volume: 380, At the Edge of the Universe: Latest Results from the Deepest Astronomical Surveys
Page: 449
Authors: Peroux, C.
Abstract: A complementary method to selecting high-redshift galaxies by emission consists of observations of absorbers along the line of sight toward a background quasar. This selection technique has a constant sensitivity at all redshifts up to z = 6 (i.e. no redshift desert) and allows selection of all types of galaxies regardless of their luminosity or star formation rate. The highest column density absorbers, the Damped Lyman-α (DLAs) systems, in particular, can be used to determine the cosmic evolution of HI gas in the Universe, ΩHI, and the global metallicity in the gas phase. Since stars are known to form from HI gas, ΩHI provides an indirect tracer of the history of star formation. Recent results from several parallel VLT programmes aiming at determining the cosmological evolution of the metallicity in the absorbing gas are presented.
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