Evolution of the population of very strong Mg ii absorbers

We present a study of the evolution of several classes of Mg II absorbers, and their corresponding Fe II absorption, over a large fraction of cosmic history: 2.3–8.7 Gyr from the big bang. Our sample consists of 87 strong ($W_{\rm r}(Mg _{II}) > 0.3$ Å) Mg II absorbers, with redshifts 0.2 < z < 2.5, measured in 81 quasar spectra obtained from the Very Large Telescope/Ultraviolet and Visual Echelle...