Photometric selection of quasars from SDSS. II. J/ApJS/180/67 ivo://CDS.VizieR/J/ApJS/180/67 doi:10.26093/cds/vizier.21800067 CDS Richards G.T. Myers A.D. Gray A.G. Riegel R.N. Nichol R.C.,Brunner R.J. Szalay A.S. Schneider D.P. Anderson S.F. 2017-06-27T06:37:32Z 2009-11-16T22:17:15Z CDS support team CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France cds-question@unistra.fr visible-astronomy sloan-photometry quasars redshifted spectroscopy We present a catalog of 1172157 quasar candidates selected from the photometric imaging data of the Sloan Digital Sky Survey (SDSS). The objects are all point sources to a limiting magnitude of i=21.3 from 8417deg^2^ of imaging from SDSS Data Release 6 (DR6). This sample extends our previous catalog by using the latest SDSS public release data and probing both ultraviolet (UV)-excess and high-redshift quasars. While the addition of high-redshift candidates reduces the overall efficiency (quasars:quasar candidates) of the catalog to ~80%, it is expected to contain no fewer than 850000 bona fide quasars, which is ~8 times the number of our previous sample and ~10 times the size of the largest spectroscopic quasar catalog. Cross-matching between our photometric catalog and spectroscopic quasar catalogs from both the SDSS and 2dF survey yields 88879 spectroscopically confirmed quasars. For judicious selection of the most robust UV-excess sources (~500000 objects in all), the efficiency is nearly 97% -more than sufficient for detailed statistical analyses. The catalog's completeness to type 1 (broad-line) quasars is expected to be no worse than 70%, with most missing objects occurring at z<0.7 and 2.5<z<3.0. In addition to classification information, we provide photometric redshift estimates (typically good to {Delta}z+/-0.3[2{sigma}]) and cross-matching with radio, X-ray, and proper-motion catalogs. Finally, we consider the catalog's utility for determining the optical luminosity function of quasars and are able to confirm the flattening of the bright-end slope of the quasar luminosity function at z~4 as compared to z~2. 2009ApJS..180...67R https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/180/67 Catalog Research IsServedBy TAP VizieR generic service IsServedBy Conesearch service related-to VII/241 : The 2dF QSO Redshift Survey (Croom+ 2004) VII/252 : SDSS-DR5 quasar catalog (Schneider+, 2007) II/282 : The SDSS Photometric Catalog, Release 6 (Adelman-McCarthy+, 2007) II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009) J/ApJS/155/257 : NBC Quasar Candidate Catalog (Richards+, 2004) http://www.sdss.org : SDSS Home Page https://cds.unistra.fr/vizier-org/licences_vizier.html https://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/180/67 https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/180/67 http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/180/67 https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/180/67 https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/180/67 http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/180/67 GET text/xml+votable https://tapvizier.cds.unistra.fr/TAPVizieR/tap Cone search capability for table J/ApJS/180/67/catalog (Catalog of quasar candidates from non-parametric Bayes classifier kernel density estimate (NBC KDE)) https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/180/67/catalog? https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/180/67/catalog? http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/180/67/catalog? 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Catalog of quasar candidates from non-parametric Bayes classifier kernel density estimate (NBC KDE) recno Record number assigned by the VizieR team. Should Not be used for identification. meta.record int Seq Unique catalog number meta.id;meta.main int primary indexed SDSS SDSS name (JHHMMSS.ss+DDMMSS.s) meta.id char zph Photometric redshift; see Weinstein et al., 2004ApJS..155..243W src.redshift float zph.L Lower limit of zphot src.redshift.phot float zph.U Upper limit of zphot src.redshift.phot float zpprob Photometric redshift range probability stat.probability float umag u band PSF ubercalibrated asinh magnitude (1) mag phot.mag;em.opt.U float e_umag Error in umag mag stat.error;phot.mag;em.opt.U float gmag g band PSF ubercalibrated asinh magnitude (1) mag phot.mag;em.opt.B float e_gmag Error in gmag mag stat.error;phot.mag;em.opt.B float rmag r band PSF ubercalibrated asinh magnitude (1) mag phot.mag;em.opt.R float e_rmag Error in rmag mag stat.error;phot.mag;em.opt.R float imag i band PSF ubercalibrated asinh magnitude (1) mag phot.mag;em.opt.I float e_imag Error in imag mag stat.error;phot.mag;em.opt.I float zmag z band PSF ubercalibrated asinh magnitude (1) mag phot.mag;em.opt.I float e_zmag Error in zmag mag stat.error;phot.mag;em.opt.I float E(B-V) The (B-V) extinction (2) mag phot.color.excess float c Concentration for star/galaxy separation (3) mag phys.size;arith.ratio float F20cm ? the 20cm (1.5GHz) flux density mJy phot.flux.density;em.radio.1500-3000MHz double nullable FX ? RASS full-band count rate (0.1-2keV) ct/s phot.count;em.X-ray float nullable pm ? Proper motion mas/yr pos.pm double nullable mov [-1/1] Flag to indicate possible moving object (4) meta.code int fz [0/1] Full z range flag, 95% star prior meta.code int lz [0/1] Low z range flag (z<=2.2), 98% star prior meta.code int mz [0/1] Mid z range flag (2.2<z<3.5), 98% star prior meta.code int hz [0/1] High z range flag (z>=3.5), 98% star prior meta.code int uv [0/1] UV-excess flag, 88% star prior; see Paper I, Cat. <J/ApJS/155/257> meta.code int log(q) Kernel density estimate (KDE) quasar probability stat.probability double log(s) Kernel density estimate (KDE) star probability stat.probability double good [-6/6] Quality flag (5) meta.code.qual int Class Previous catalog object classification (6) meta.code.class;src.class;meta.table char z ? Previous catalog object redshift src.redshift float nullable Sloan Display the SDSS data from the SDSS site meta.ref.url char RAJ2000 Right Ascension in decimal degrees (J2000) deg pos.eq.ra;meta.main indexed DEJ2000 Declination in decimal degrees (J2000) deg pos.eq.dec;meta.main indexed