J/MNRAS/370/1034ivo://CDS.VizieR/J/MNRAS/370/1034doi:10.26093/cds/vizier.73701034CDSCarballo R.Gonzalez-Serrano J.I.Montenegro-Montes F.M.Benn C.R.,Mack K.-H.Pedani M.Vigotti M.2024-07-02T20:17:50Z2007-04-28T23:22:27ZCDS support team

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

cds-question@unistra.frquasarsradio-sourcesvisible-astronomyphotographic-photometryWe selected from the VLA FIRST survey a sample of 94 objects with star-like counterparts in the Sloan Digital Sky Survey (SDSS), and with APM POSS-I colour O-E>=2, i.e. consistent with their being high-redshift quasars. 78 of the 94 candidates can be classified spectroscopically on the basis of either published data (mainly SDSS) or the observations presented here. The fractions of QSOs (51 out of 78) and redshift z>3 QSOs (23 out of 78, 29 per cent) are comparable to those found in other photometric searches for high-redshift QSOs. We confirm that selecting colour O-E>=2 ensures inclusion of all QSOs with 3.7<=z<=4.4. The fraction of 2<=z<=4.4 QSOs with broad absorption lines (BALs) is 27+/-10 per cent (7/26) and the estimated BAL fraction for radio-loud QSOs is at least as high as for optically selected QSOs (~13 per cent). Both the high BAL fraction and the high fraction of low-ionization BALs among BALs (four to five out of seven) in our sample, compared to previous work, are likely due to the red colour selection O-E>=2.2006MNRAS.370.1034Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/370/1034CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVIII/71 : The FIRST Survey Catalog, Version 03Apr11 (Becker+ 2003)J/ApJS/143/1 : FIRST-APM Source Catalog (McMahon+, 2002)http://www.sdss.org : SDSS Home Pagehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/370/1034https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/370/1034http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/370/1034https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/370/1034https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/370/1034http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/370/1034GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/370/1034/table2 (Radio/optical properties and spectroscopic classification of the 94 candidates)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/370/1034/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/370/1034/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/370/1034/table2?GETtext/xml+votable180.050000true122.185291744.06608330.0055555555555555566/5035 5119 5479 5485 5487 5496 5533 5563 5592 5598 5604 5744 5771 5824 5873 5886 5903 5914 5919 5927 5935 5950 5957 5992 6005 6009 6046 6056 6096 6464 6480 6487 6507 6600 7204 7212 7237 7248 9372 9395 9397 9412 9432 9453 9464 9747 9758 9783 9789 9805 9841 9901-9902 9984 9988 10607 10623 10651 10655 10669 10694 10719 10748 10941 10956 10981 10997 11016 11063 11069 11080 11095 11099 11111-11112 11130 11161 11202 11232 11270 11290 11303 11312 11355 11368 11396 11404 11438 11449 11461https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/370/1034?format=asciiOpticalRadiodefaultJ/MNRAS/370/1034/table2Radio/optical properties and spectroscopic classification of the 94 candidatesz? Redshiftsrc.redshiftfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000SDSS Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000SDSS Declination (J2000)pos.eq.dec;meta.mainSepRadio-optical (FIRST-SDSS) separationarcsecpos.angDistancefloatS1.4GHzFIRST Flux density at 1.4GHz (integrated for S1.4GHz>10mJy, otherwise peak)mJyphot.flux.density;em.radio.750-1500MHzfloatE(B-V)Galactic extinction (Schlegel et al., 1998ApJ...500..525S)magphot.color.excessfloatEmagE magnitude from McMahon et al. (2002, Cat. <J/ApJS/143/1>)magphot.mag;em.opt.Rfloatl_O-ELimit flag on O-Emeta.code.errorcharO-EO-E colour index from McMahon et al. (2002, Cat. <J/ApJS/143/1>) (1)magphot.color;em.opt.B;em.opt.RfloatRel[DR3 DR4] SDSS Source of spectrum, spectroscopic classification, and redshiftmeta.softwarecharr_Sp[1/8]? Other Source of spectrum, spectroscopic classification, and redshift (2)meta.refintnullableSpSpectroscopic classificationsrc.classcharRemRemarks (3)meta.notecharSDSSDisplay the SDSS datameta.ref.urlcharFIRSTDisplay the FIRST data (Cat. VIII/71)meta.ref.urlcharAPMDisplay the APM data (Cat. J/ApJS/143/1)meta.ref.urlchar