The XQR-30 Metal Absorber Catalog: 778 Absorption Systems Spanning 2 < z < 6.5

Abstract

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.

29 pages and 14 figures including 2 appendices. Accepted for publication in MNRAS. The metal absorber catalogue can be downloaded from https://github.com/XQR-30/Metal-catalogue. Contents unchanged from v1 apart from change to author list

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Cited by in corpus (19)

• XQR-30: the ultimate XSHOOTER quasar sample at the reionization epoch
• Damping Wing-Like Features in the Stacked Ly$\alpha$ Forest: Potential Neutral Hydrogen Islands at $z<6$
• Damping wings in the Lyman-α forest: a model-independent measurement of the neutral fraction at 5.4<z<6.1
• Multi-phase black-hole feedback and a bright [CII] halo in a Lo-BAL quasar at $z\sim 6.6$
• Examining the Decline in the C IV Content of the Universe over 4.3 < z < 6.3 using the E-XQR-30 Sample
• Metal enrichment and evolution in four z > 6.5 quasar sightlines observed with JWST/NIRSpec
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• Chemical Diagnostics to Unveil Environments Enriched by First Stars
• Discovery and characterization of 25 new quasars at 4.6 < z < 6.9 from wide-field multi-band surveys
• A SPectroscopic survey of biased halos In the Reionization Era (ASPIRE): JWST Discovers an Overdensity around a Metal Absorption-selected Galaxy at $z\sim 5.5$
• Optical and near-infrared spectroscopy of quasars at $z>6.5$: public data release and composite spectrum
• An extremely metal-poor Lyman $\alpha$ emitter candidate at $z=6$ revealed through absorption spectroscopy
• Ly$\alpha$ Emission from [OIII] Emitters Near Reionization: The role of environment in galaxy Ly$\alpha$ detection
• Automated quasar continuum estimation using neural networks: a comparative study of deep-learning architectures
• Multi-phase investigation of outflows in the circumgalactic and interstellar media of luminous quasars at z~5
• Measuring the IGM correlation length at 5<z<6.1: a fast change at the end of Reionization
• The clustering of C IV and Si IV at the end of reionisation: A perspective from the E-XQR-30 survey
• 4MOST ChANGES: Catalog of high-redshift quasar candidates (4.5 < $z$ < 7) selected with SED fitting