Fox, Andrew J.Ledoux, C.Petitjean, Patricket al.2012-03-052012-03-052007-07-27http://hdl.handle.net/11007/463We present a study of Civ absorption in a sample of 63 damped Lyman-α (DLA) systems and 11 sub-DLAs in the redshift range 1.75<zabs<3.61, using a dataset of high-resolution (6.6 kms −1 FWHM), high signal-to-noise VLT/UVES spectra. Narrow and broad Civ absorption line components indicate the presence of both warm, photoionized and hot, collisionally ionized gas. We report new correlations between the metallicity (measured in the neutral-phase) and each of the Civ column density, the Civ total line width, and the maximum Civ velocity. We explore the effect on these correlations of the sub-DLAs, the proximate DLAs (defined as those within 5 000 kms −1 of the quasar), the saturated absorbers, and the metal line used to measure the metallicity, and we find the correlations to be robust. There is no evidence for any difference between the measured properties of DLA Civ and sub-DLA Civ. In 25 DLAs and 4 sub-DLAs, covering 2.5 dex in [Z/H], we directly observe Civ moving above the escape speed, where vesc is derived from the total line width of the neutral gas profiles. These high-velocity Civ clouds, unbound from the central potential well, can be interpreted as highly ionized outflowing winds, which are predicted by numerical simulations of galaxy feedback. The distribution of Civ column density in DLAs and sub-DLAs is similar to the distribution in Lyman Break galaxies, where winds are directly observed, supporting the idea that supernova feedback creates the ionized gas in DLAs. The unbound Civ absorbers show a median mass flow rate of ∼22 (r/40 kpc)M⊙ yr −1 , where r is the characteristic Civ radius. Their kinetic energy fluxes are large enough that a star formation rate (SFR) of ∼ 2M⊙ yr −1 is required to power them.enQuasarsAbsorption linesCosmologyObservations galaxiesHigh-redshift galaxiesHalos galaxiesArticle