J/AJ/155/131ivo://CDS.VizieR/J/AJ/155/131doi:10.26093/cds/vizier.51550131CDSMcGreer I.D.Fan X.Jiang L.Cai Z.2020-02-03T10:42:25Z2018-11-13T07:36:15ZCDS support team

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

cds-question@unistra.frquasarsredshiftedvisible-astronomysloan-photometryWe present results from a spectroscopic survey of z~5 quasars in the CFHT Legacy Survey (Cat. II/317). Using both optical color selection and a likelihood method, we select 97 candidates over an area of 105 deg^2^ to a limit of i_AB_<23.2, and 7 candidates in the range 23.2<i_AB_<23.7 over an area of 18.5 deg^2^. Spectroscopic observations for 43 candidates were obtained with Gemini, MMT, and Large Binocular Telescope, of which 37 are z>4 quasars. This sample extends measurements of the quasar luminosity function ~1.5 mag fainter than our previous work in Sloan Digital Sky Survey Stripe 82. The resulting luminosity function is in good agreement with our previous results, and suggests that the faint end slope is not steep. We perform a detailed examination of our survey completeness, particularly the impact of the Ly{alpha} emission assumed in our quasar spectral models, and find hints that the observed Ly{alpha} emission from faint z~5 quasars is weaker than for z~3 quasars at a similar luminosity. Our results strongly disfavor a significant contribution of faint quasars to the hydrogen-ionizing background at z=5.2018AJ....155..131Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/155/131CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)II/317 : The CFHTLS Survey (T0007 release) (Hudelot+ 2012)J/AJ/121/2308 : Sloan Digital Sky Survey quasar photometry (Richards+, 2001)J/AJ/131/2766 : Quasar luminosity function from SDSS-DR3 (Richards+, 2006)J/ApJ/710/1498 : QSO luminosity function at z~4 (Glikman+, 2010)J/A+A/548/A66 : SDSS Quasar Catalog, DR9Q (Paris+, 2012)J/ApJ/755/169 : 3<z<5 quasar luminosity function in the COSMOSJ/ApJ/768/105 : z~5 QSO luminosity function from SDSS Stripe 82J/ApJ/773/14 : BOSS: quasar luminosity function (Ross+, 2013)J/ApJ/819/24 : z>4.5 QSOs with SDSS and WISE. I. Opt. spectra (Wang+, 2016)J/ApJ/829/33 : Luminous of high-z QSOs with SDSS and WISE. II (Yang+, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/155/131https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/155/131http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/155/131https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/155/131https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/155/131http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/155/131GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/155/131/Sample (Complete quasar candidates with i_AB_<23.2 (table 3) and 23.2<i_AB_<23.7 (table 4))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/155/131/Sample?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/155/131/Sample?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/155/131/Sample?GETtext/xml+votable180.050000true30.2517083-5.87505560.005555555555555556Cone search capability for table J/AJ/155/131/table5 (Quasars with spectroscopy not included in final candidate sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/155/131/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/155/131/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/155/131/table5?GETtext/xml+votable180.050000true21.43954176.04752780.0055555555555555565/4416 4758 6/4120 4627 7609 9687 10246 10268 10741 10742 10745 10747 10748 10750 11399 11402 11403 11416 11418 11419 11422 11429 11430 11432 11433 11434 11436 11437 11441 11443 11444 11445 11447 11449 11450 11780 17494 17495 17502 17503 17674 17678 17679 17680 17682 17690 17691 17692 17696 17698 17699 17700 17701 17703 17705 17708 17709 17714 18226 19025 19027 19030 19036 19037 19038 19050 19053 19057 19058 19064 19068 19112 22395 28165 28334 28429 30064 36607 36776 36778 36780 36781 36783 36792 36793 36795 36798 40943 49151https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/155/131?format=asciiOpticaldefaultJ/AJ/155/131/SampleComplete quasar candidates with i_AB_<23.2 (table 3) and 23.2<i_AB_<23.7 (table 4)SimbadNameSimbad column added by the CDSmeta.idcharzmag[19.15/23.37] z band AB magnitude (2)magphot.mag;em.opt.IfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintimagInti band magnitude interval of samplemeta.noteRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainl_gmag[>] Limit flag on gmag (1)meta.code.errorchargmag[23.87/29.58] g band AB magnitude (2)magphot.mag;em.opt.Bfloate_gmag[0.02/1]? Uncertainty in gmag (2)magstat.error;phot.mag;em.opt.Bfloatnullablermag[21.22/26.18] r band AB magnitude (2)magphot.mag;em.opt.Rfloate_rmag[0.01/0.51] Uncertainty in rmag (2)magstat.error;phot.mag;em.opt.Rfloatimag[19.38/23.69] i band AB magnitude (2)magphot.mag;em.opt.Ifloate_imag[0.01/0.05] Uncertainty in imag (2)magstat.error;phot.mag;em.opt.Ifloate_zmag[0.01/0.11] Uncertainty in zmag (2)magstat.error;phot.mag;em.opt.IfloatPQso[0/1] Summed probability that this object is in the full redshift range (4.5<z<5.8)stat.fit.goodnessfloatPQsoMidz[0/1] Probability that this object is a QSO with 4.8<z<5.2stat.fit.goodnessfloatM1450[-27.7/-22.7]? Absolute 1450{AA} magnitude (3)meta.notefloatnullablez[4.2/5.42]? Redshift (3)src.redshiftfloatnullableu_z[?] Uncertainty flag on z (not in Table 4)meta.code.error;src.redshiftcharn_z[abcde] Note on z (not in Table 4) (4)meta.notecharTelTelescope (MMT, Gem, LBT or Sloan) (not in Table 4) (3)meta.id;instr.telcharJ/AJ/155/131/table5Quasars with spectroscopy not included in final candidate samplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainz[4.18/5.31]? Redshift (1)src.redshiftfloatnullableSourceImaging source from which the object was selected (2)meta.idchar