J/ApJ/462/614ivo://CDS.VizieR/J/ApJ/462/614doi:10.26093/cds/vizier.14620614CDSHall P.B.Osmer P.S.Green R.F.Porter A.C.Warren S.J.2013-03-05T06:34:55Z1997-12-09T20:59:09ZCDS support team

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

cds-question@unistra.frquasarsgalaxiesphotometrysurveysWe have used the Kitt Peak National Observatory 4m Mayall telescope to image 0.83 square degrees of sky in six fields at high galactic latitude in six filters spanning 3000-10000A to magnitude limits ranging from 22.1 to 23.8. As a first use of this database, we have conducted a multicolor survey for quasars. We discuss various methods of selecting outliers in different color-color diagrams and multicolor space that have been used to identify quasars at all redshifts from their colors alone. We discuss the initial results of our program of spectroscopic identification which has so far resulted in the identification of over 40 faint quasars, including one a z>4, a similar number of compact narrow emission-line galaxies, and a number of unusual and potentially interesting stars. We use these spectroscopic results, along with extensive simulations of quasar spectra, to study the efficiency of our candidate selection procedures. Finally, we compare the number counts of our quasars and quasar candidates to the expected numbers based on previous studies of the quasar luminosity function. The agreement of our observations with these expectations is good in most cases. However, we do estimate that our survey contains more quasars with B<21 and z<2.3 than expected from the results published by Koo & Kron in (1988ApJ...325...92K) and more z>3 quasars than expected from the results published by Warren, Hewett & Osmer in (1994ApJ...421..412W), both at the 3 {sigma} level. Additional spectroscopic observations will be required to confirm or refute these excesses.1996ApJ...462..614Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/462/614CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJS/104/185 : A deep multicolor survey. I. (Hall+ 1996)J/AJ/114/2269 : A deep multicolor survey. III (Kennefick+ 1997)J/ApJS/119/189 : A deep multicolor Survey. IV. (Osmer+ 1998)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/462/614https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/462/614http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/462/614https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/462/614https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/462/614http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/462/614GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/462/614/table1 (Quasars: identification)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/462/614/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/462/614/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/462/614/table1?GETtext/xml+votable180.050000true15.4068695-0.58955160.005555555555555556Cone search capability for table J/ApJ/462/614/table2 (Compact narrow emission-line galaxies: identifications)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/462/614/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/462/614/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/462/614/table2?GETtext/xml+votable180.050000true15.4238591-0.72850910.0055555555555555566/10049 10051 18020 18825 18827 18830 18994 26002https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/462/614?format=asciiOpticaldefaultJ/ApJ/462/614/table1Quasars: identificationrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNoSequential numbermeta.recordintNameDMS or N designation (1)meta.idcharRA1950Right ascension (1950.0)pos.eq.ra;meta.mainDE1950Declination (1950.0)pos.eq.dec;meta.mainBmagB magnitudemagphot.mag;em.opt.Bfloatz? Redshiftsrc.redshiftfloatnullableu_z[?] Uncertainty flag on zmeta.code.error;src.redshiftcharNotesNotesmeta.notechar_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data)pos.eq.ranullableindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data)pos.eq.decnullableindexedJ/ApJ/462/614/table2Compact narrow emission-line galaxies: identificationsz? Redshiftsrc.redshiftfloatnullableu_z[?] Uncertainty flag on zmeta.code.error;src.redshiftcharNotesNotesmeta.notecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNoSequential numbermeta.recordintNameDMS or N designation (1)meta.idcharRA1950Right ascension (1950.0)pos.eq.ra;meta.mainDE1950Declination (1950.0)pos.eq.dec;meta.mainBmagB magnitudemagphot.mag;em.opt.Bfloat_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data)pos.eq.ranullableindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data)pos.eq.decnullableindexed