The Sloan Digital Sky Survey Quasar Catalog: Fourteenth Data Release

Abstract: We present the Data Release 14 Quasar catalog (DR14Q) from the extended Baryon Oscillation Spectroscopic Survey (eBOSS) of the Sloan Digital Sky Survey IV (SDSS-IV). This catalog includes all SDSS-IV/eBOSS objects that were spectroscopically targeted as quasar candidates and that are confirmed as quasars via a new automated procedure combined with a partial visual inspection of spectra, have luminosities $M_{\rm i} \left[ z=2 \right] < -20.5$ (in a $\Lambda$CDM cosmology with $H_0 = 70 \ {\rm km \ s^{-1} \ Mpc ^{-1}}$, $\Omega_{\rm M} = 0.3$, and $\Omega_{\rm \Lambda} = 0.7$), and either display at least one emission line with a full width at half maximum (FWHM) larger than $500 \ {\rm km \ s^{-1}}$ or, if not, have interesting/complex absorption features. The catalog also includes previously spectroscopically-confirmed quasars from SDSS-I, II and III. The catalog contains 526,356 quasars 144,046 are new discoveries since the beginning of SDSS-IV) detected over 9,376 deg$^2$ (2,044 deg$^2$ having new spectroscopic data available) with robust identification and redshift measured by a combination of principal component eigenspectra. The catalog is estimated to have about 0.5% contamination. The catalog identifies 21,877 broad absorption line quasars and lists their characteristics. For each object, the catalog presents SDSS five-band CCD-based photometry with typical accuracy of 0.03 mag. The catalog also contains X-ray, ultraviolet, near-infrared, and radio emission properties of the quasars, when available, from other large-area surveys.

• The paper presents the DR14Q catalog, adding 144,046 new quasar discoveries and refined redshift measurements for enhanced BAO studies.
• It uses extensive spectroscopic data and rigorous visual inspections to achieve a contamination rate of only 0.5%, ensuring high data quality.
• The catalog integrates multi-wavelength observations from surveys like FIRST, GALEX, 2MASS, and XMM-Newton, deepening insights into quasar properties and cosmic structure.

Overview of the Fourteenth Data Release Quasar Catalog from the Sloan Digital Sky Survey

The paper "The Sloan Digital Sky Survey Quasar Catalog: Fourteenth Data Release" presents the DR14Q catalog, which is a comprehensive compilation of quasar data derived from the extended Baryon Oscillation Spectroscopic Survey (eBOSS) under the Sloan Digital Sky Survey IV (SDSS-IV). This catalog stands as a key resource in astronomy, offering refined data on quasars crucial for various cosmological and astrophysical research endeavors.

The DR14Q catalog encompasses a total of 526,356 quasars, which marks an increase of approximately 144,046 new quasar discoveries since the previous data release. These quasars span observations conducted over an expansive area of 9,376 square degrees, with newly integrated spectroscopic data extending over an added 2,044 square degrees. The data extraction and cataloging processes of the SDSS allow for a substantial improvement in the quasar detection surface density, especially notable for the redshift range of 0.9 to 2.2.

Quasars have been spectroscopically targeted and confirmed via a combination of automated procedures and exhaustive visual inspections, which together assure a contamination rate of only 0.5%. The catalog holds great relevance for studies focused on large-scale structures in the universe due to its robust and exquisitely measured redshifts, achieved by employing calibrated automated procedures and the use of specific emission lines such as \ion{Mg}{ii}.

Numerical Backbone and Implications

The catalog presents quasars with redshifts predominantly below 2, thereby addressing the deficit in earlier quasar surveys which primarily targeted higher redshift bands. The strategic goal of eBOSS is clearly underscored by its inclusion of quasars in the 0.9 < z < 2.2 range, achieving an impressive density of 58 such quasars per square degree for precise Baryon Acoustic Oscillation (BAO) measurements.

The DR14Q release is enriched with multifaceted data from cross-matched large-area surveys, such as the FIRST for radio properties, GALEX for ultraviolet emissions, 2MASS and UKIDSS for infrared signatures, and X-ray detections from ROSAT and XMM-Newton. This interwoven dataset maximizes the scientific output by integrating multi-wavelength observations.

From a future perspective, the insights derived from this extensive spectral repository pave the way for deeper exploration of Evolutionary Black Hole models, surveys on the Intergalactic Medium (IGM), and refinements of quasar luminosity functions. These facets hold potential to reframe our understanding of the universe's large-scale architecture and evolution.

Immediate and Long-term Relevance

Practically, the availability of DR14Q data aids in discerning properties of Broad Absorption Line (BAL) quasars, notably enhanced by the automated detection methodologies which integrate robust PCA-based redshift evaluations.

The release catalyzes future spectroscopic surveys by setting a rigorous benchmark for redshift adequacy and spectral purity. Enhanced intermixed data facilitates a better understanding of quasar properties like clustering potentials and dynamic evolution that are pivotal for numerous theoretical and observational models in cosmology.

In conclusion, the DR14Q catalog is a testament to the ongoing progress of the SDSS-IV/eBOSS project. It holds immense value for both current theoretical pursuits and future explorations, making it a cornerstone database supporting astrophysical research aimed at illuminating the cosmos. The strategic alignment of its data acquisition and analysis processes ensures that it remains a central asset for quasar research and for probing the universe's enigmatic constituents.