Chemical fingerprints in quasar spectra: Intervening metal absorbers from redshift 2 to 6

I identify a population of singly ionised Magnesium absorbers which most likely trace the halos hosting a population of numerous and faint galaxies whose brightness lies below the current detection limit of existing telescopes. I present full population statistics of the triply ionised Carbon (CIV) and Silicon ions during the second billion years of cosmological evolution of the Universe. I find that a significant fraction of CIV is held in systems which are most likely tracing a multi-phase medium where hot and cold gas is mixing at the interface between the circumgalactic and intergalactic mediums.