The XQR-30 Metal Absorber Catalog: 778 Absorption Systems Spanning 2 < z < 6 5 by Rebecca L. Davies et al. on Tuesday 29 November

Intervening metal absorption lines in the spectra of z > 6 quasars are

fundamental probes of the ionization state and chemical composition of

circumgalactic and intergalactic gas near the end of the reionization epoch.

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 catalog of 778 systems

showing absorption in one or more of MgII (360 systems), FeII (184), CII (46),

CIV (479), SiIV (127), and NV (13) which span 2 < z < 6.5. This catalog

significantly expands on existing samples of z > 5 absorbers, especially for

CIV and SiIV which are important probes of the ionizing photon background at

high redshift. The sample is 50% (90%) complete for rest-frame equivalent

widths W > 0.03AA (0.09AA). We publicly release the absorber catalog along with

completeness statistics and a Python script to compute the absorption search

path for different ions and redshift ranges. This dataset is a key legacy

resource for studies of enriched gas from the era of galaxy assembly to cosmic

noon, and paves the way for even higher redshift studies with the James Webb

Space Telescope and 30m-class telescopes.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.15816v1