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Description
This is a compendium of 829666 type-I QSOs and AGN, largely complete from the literature to 30 April 2021 including SDSS-DR16 quasars and VLASS radio. Also included are 703348 candidates which are calculated as 60%-100% likely to be quasars, including 225051 which are radio/X-ray associated. Type-II and Bl Lac objects are also included, bringing the total count to 1573824. Gaia-DR2 astrometry is used where available, amounting to ~66% of all objects. Changes from version 7.1 are: (1) Quasars added from publications to 30 April 2021. (2) The VLASS Quick Look radio catalog is included, which adds 34189 new radio core associations and 6793 probable double radio lobe associations. (3) Ongoing audits of SDSS & LAMOST quasars have led to a few additions & drops. Some WISEA-supported SDSS/LAMOST pipeline quasars are now accepted which were otherwise marginal. Also some likely galaxies removed. Low-confidence/quality or questionable objects (so deemed by their researchers) are not included in Milliquas. Additional quality cuts can apply as detailed in the HMQ paper (Flesch, 2015PASA...32...10F). Full QSO/AGN classification is via spectral lines, thus hidden / occluded objects may be absent from Milliquas. Two NIQs offset <2-arcsecs can be reported as a single object if within the same host. The aim here is to present one unique reliable object per each data row. The catalog format is simple, each object is shown as one line bearing the J2000 coordinates, its original name, object class, red and blue optical magnitudes, PSF class, redshift, the citations for the name and redshift, plus up to four radio/X-ray identifiers where applicable. Please cite as Milliquas v7.2, Flesch, E.W. 2021, arXiv:2105.12985 or as Milliquas v7.2 (2021) update, Flesch, E.W. 2015PASA...32...10F. Questions/comments/praise/complaints may be directed to me at eric(at)flesch.org.
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