Identification confusion and blending concealment in the SDSS-DR16 Quasar catalogues -- 40 new quasars and 82 false quasars identified

Abstract

The SDSS-DR16 Quasar Superset and pipeline catalogues are searched for undeclared quasars which were concealed by or confused with other objects, usually due to incomplete deblending. Forty such quasars with redshifts are found and herewith presented. Also, 82 entries in the SDSS-DR16Q main quasar catalogue are shown to be non-quasars, some also due to incomplete deblending, especially "line poachers". Other non-quasars are shown to be star spikes or moving stars or other types, and 7 new quasars are identified from analysis of "unplugged" spectra. These numbers are tiny compared with the millions of DR16 spectra, but highlight some heretofore overlooked systematics. The deblending issue is discussed throughout.

Accepted by Monthly Notices of the Royal Astronomical Society. 14 pages, 22 figures, 2 tables

References in corpus (3)

• The Sloan Digital Sky Survey Quasar Catalog: Sixteenth Data Release
• The Sloan Digital Sky Survey Quasar Catalog: twelfth data release
• The 2dF-SDSS LRG and QSO Survey: The spectroscopic QSO catalogue

Cited by in corpus (8)

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• CatNorth: An Improved Gaia DR3 Quasar Candidate Catalog with Pan-STARRS1 and CatWISE
• The accretion of a solar mass per day by a 17-billion solar mass black hole
• Deep Learning in Searching the Spectroscopic Redshift of Quasars
• The intrinsic reddening of the Magellanic Clouds as traced by background galaxies -- III. The Large Magellanic Cloud
• A search for gravitationally lensed supernovae within the Zwicky Transient Facility public survey
• FNet II: Spectral Classification of Quasars, Galaxies, Stars, and broad absorption line (BAL) Quasars
• A Treasure Hunt in the Pool of Spectra Classified as High-redshift QSOs by the Spectroscopic Pipeline of the SDSS DR16