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We have collected data for 69 Damped Lyman-alpha (DLA) systems, to investigate the chemical evolution of galaxies in the redshift interval 0.0 < z < 4.4. In doing that, we have adopted the most general approach used so far to correct for dust depletion. The best solution, obtained through chi^2 minimization, gives as output parameters the global DLA metallicity and the dust-to-metals ratio. Clear evolution of the metallicity vs. redshift is found (99.99% significance level), with average values going from ~1/30 solar at z~4.1 to ~3/5 solar at z~0.5. We also find that the majority of DLAs (~60%) shows dust depletion patterns which most closely resemble that of the warm halo clouds in the Milky Way, and have dust-to-metals ratios very close to warm halo clouds.
We report evidence for an anti-correlation between spin temperature $T_s$ and metallicity [Z/H], detected at $3.6 sigma$ significance in a sample of 26 damped Lyman-$alpha$ absorbers (DLAs) at redshifts $0.09 < z < 3.45$. The anti-correlation is dete
Based on the disk galaxy formation theory within the framework of standard LCDM hierarchical picture, we selected modelled DLAs, according to their observational criterion, by Monte Carlo simulation with the random inclinations being considered, to e
We examine the properties of damped Lyman-$alpha$ absorbers (DLAs) emerging from a single set of cosmological initial conditions in two state-of-the-art cosmological hydrodynamic simulations: {sc Simba} and {sc Technicolor Dawn}. The former includes
We have identified a metal-strong (logN(Zn+) > 13.15 or logN(Si+) > 15.95) DLA (MSDLA) population from an automated quasar (QSO) absorber search in the Sloan Digital Sky Survey Data Release 3 (SDSS-DR3) quasar sample, and find that MSDLAs comprise ~5
We report evidence for a bimodality in damped Ly systems (DLAs). Using [C II] 158 mu cooling rates, lc, we find a distribution with peaks at lc=10^-27.4 and 10^-26.6 ergs s^-1 H^-1 separated by a trough at lc^crit ~= lc < 10^-27.0 ergs s^-1 H^-1. We