J/ApJ/755/169ivo://CDS.VizieR/J/ApJ/755/169doi:10.26093/cds/vizier.17550169CDSMasters D.Capak P.Salvato M.Civano F.Mobasher B.Siana B.,Hasinger G.Impey C.D.Nagao T.Trump J.R.Ikeda H.Elvis M.,Scoville N.2022-10-05T07:38:10Z2017-09-11T08:53:07ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frquasarsphotometryredshiftedx-ray-sourcesWe investigate the high-redshift quasar luminosity function (QLF) down to an apparent magnitude of I_AB_=25 in the Cosmic Evolution Survey (COSMOS). Careful analysis of the extensive COSMOS photometry and imaging data allows us to identify and remove stellar and low-redshift contaminants, enabling a selection that is nearly complete for type-1 quasars at the redshifts of interest. We find 155 likely quasars at z>3.1, 39 of which have prior spectroscopic confirmation. We present our sample in detail and use these confirmed and likely quasars to compute the rest-frame UV QLF in the redshift bins 3.1<z<3.5 and 3.5<z<5. The space density of faint quasars decreases by roughly a factor of four from z~3.2 to z~4, with faint-end slopes of {beta}~-1.7 at both redshifts. The decline in space density of faint optical quasars at z>3 is similar to what has been found for more luminous optical and X-ray quasars. We compare the rest-frame UV luminosity functions found here with the X-ray luminosity function at z>3, and find that they evolve similarly between z~3.2 and z~4; however, the different normalizations imply that roughly 75% of X-ray bright active galactic nuclei (AGNs) at z~3-4 are optically obscured. This fraction is higher than found at lower redshift and may imply that the obscured, type-2 fraction continues to increase with redshift at least to z~4. Finally, the implications of the results derived here for the contribution of quasars to cosmic reionization are discussed.2012ApJ...755..169Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/755/169CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/284 : COSMOS Multi-Wavelength Photometry Catalog (Capak+, 2007)J/ApJ/690/1236 : COSMOS photometric redshift catalog (Ilbert+, 2009)J/ApJ/693/8 : High-redshift QSOs in the COSMOS survey (Brusa+, 2009)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/755/169https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/755/169http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/755/169https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/755/169https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/755/169http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/755/169GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/755/169/table3 (Summary of the Likely Quasars Found Here and Used to Compute the Luminosity Function)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/755/169/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/755/169/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/755/169/table3?GETtext/xml+votable180.050000true149.853961.75367190.0055555555555555565/6814 6/27245 27247https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/755/169?format=asciiX-raydefaultJ/ApJ/755/169/table3Summary of the Likely Quasars Found Here and Used to Compute the Luminosity FunctionrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID[115356/1970813] Quasar identifiermeta.id;meta.mainintRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainImagAuto I band magnitude (AB)magphot.mag;em.opt.IfloatzestRedshift estimated based on visual examinationsrc.redshift;pos.heliocentricfloatzqsoPhotometric redshift from COSMOS (Ilbert et al. 2009, J/ApJ/690/1236)src.redshift.photfloatzspec? Spectroscopic redshiftsrc.redshiftfloatnullablezusedRedshift adopted in computing the luminosity functionsrc.redshift;pos.heliocentricfloatFlag[2/4] Confidence flag we assigned the source based on visual examination (1)meta.code.errorintX-ray[yes/no ] Source detected in X-ray ?meta.codecharM1450Derived absolute magnitude M1450 (1450{AA})magphys.magAbsfloatSimbadSimbad column added by the CDSmeta.ref.urlchar