XQR-30 quasars absorption systems properties

Large absorber samples are required to robustly measure typical absorber properties and to refine models of the synthesis, transport, and ionization of metals in the early Universe. The Ultimate XSHOOTER legacy survey of quasars at z ~ 5.8-6.6 (XQR-30) has obtained high signal-to-noise spectra of 30 luminous quasars, nearly quadrupling the existing sample of 12 high quality z ~ 6 quasar spectra.

We use this unprecedented sample to construct a catalogue of 778 systems showing absorption in one or more of Mg II (360 systems), Fe II (184), C II (46), C IV (479), Si IV (127), and N V (13) which span 2 <~ z <~ 6.5. This catalogue significantly expands on existing samples of z ~> 5 absorbers, especially for C IV and Si IV which are important probes of the ionizing photon background at high redshift. The sample is 50 per cent (90 per cent) complete for rest-frame equivalent widths W ~> 0.03 {AA} (0.09 {AA}).