J/AJ/106/848ivo://CDS.VizieR/J/AJ/106/848doi:10.26093/cds/vizier.51060848CDSDrinkwater M.J.Webster R.L.Thomas P.A.2023-04-06T16:50:06Z1998-10-02T17:18:33ZCDS support team

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

cds-question@unistra.frquasarsinfrared-photometryThe results of a large R-band imaging survey of 71 bright (m(V)<18) quasars are presented. The quasars were chosen from published samples which have intermediate resolution optical spectroscopy available, so the presence of low redshift Mg II absorption lines can be determined. We have searched our data for galaxies close to the line-of-sight to the quasars, which we might be able to identify with the absorption systems. We find a high coincidence between galaxies very near the line-of-sight and quasars showing absorption systems in their spectra, a result consistent with other studies. These galaxies have a mean luminosity of 0.5L_star_ (assuming they lie at the absorption redshift). The distribution of impact parameters between the galaxies and the quasars extends with a flat distribution to large radii (>30h^-1^kpc). This suggests that the absorption systems may not be gravitationally bound to the observed galaxies, but may be part of larger extended systems. We also find a significant number of galaxies near the line-of-sight to the quasar where no absorption is seen in the quasar spectrum. The selection of our quasars is unbiased with respect to galaxies near the line-of-sight, so we can compare the observed number of absorption systems to that predicted by a simple model with a constant covering factor in Mg II absorbing gas within a maximum radius of each detected galaxy. The model is consistent with a covering factor of unity, but allowing for incompleteness in the detection of galaxies, the covering factor is less than unity. The redshifts of the galaxies are required to confirm this result.1993AJ....106..848Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/106/848CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/106/848https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/106/848http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/106/848https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/106/848https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/106/848http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/106/848GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/106/848/table1 (Quasars observed)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/106/848/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/106/848/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/106/848/table1?GETtext/xml+votable180.050000true108.260062711.7710230.0055555555555555566/4322 4333 4345 4351 4448 4693 4698 5264 5306 6252 6264 7349 7424 7426 7488 8300 8523 8638 8709 8753 8858 9181 9402 9633 10084 10217 10298 10385 10401 10416 10423 10495 10501 10769 10774 10801 11099 11723 11845 12684 15067 19190 19398 21714 22452 25302 25789 25986 26100 26125 26614 26920 26966 27005 27009 27025 27127 27423 27717 27756 27762 27814 27981 28216 28532 28538 28666 31333 31735 325272.4622242610829604e-19 3.264051565855503e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/106/848?format=asciiInfrareddefaultJ/AJ/106/848/table1Quasars observedrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintQSOQuasar namemeta.id;meta.maincharType[RXCO ] Detection technique (1)instr.saturationcharRA1950Right ascension 1950.0pos.eq.ra;meta.mainDE1950Declination 1950.0pos.eq.dec;meta.mainVmagQuasar V magnitudemagphot.mag;em.opt.VfloatzQuasar redshift (Data in bytes 1-48 taken from Hewitt & Burbidge 1987, ApJS, 63, 1, and Hewitt & Burbidge 1989, ApJS, 69, 1)src.redshiftfloatz1Minimum redshift at which Mg II might be observed in the published spectrasrc.redshiftfloatz2Maximum redshift at which Mg II might be observed in the published spectrasrc.redshiftfloatzab1[]? Redshift of any Mg II absorption systemssrc.redshiftfloatnullablezab2[]? Redshift of any Mg II absorption systemssrc.redshiftfloatnullabler_zReference for the published spectra, parentheses signifying a non-detection (2)meta.ref;pos.framecharDateDate observed (UT)time.epochnullableEpx.TExposure timestime.duration;obs.exposureintFWHMFWHM seeingarcsecinstr.obsty.seeingfloatRmagQuasar R magnitudemagphot.mag;em.opt.RfloatNotePhotometry flag (3)meta.notecharRmaglLimiting R magnitude of image (the magnitude of the faintest object for which the formal error in the magnitude was less than 0.2 mag)magphot.magfloat_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/AJ/106/848/table3aQuasar parametersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintQSOQuasar namemeta.id;meta.maincharzQuasar redshiftsrc.redshiftfloatSeeingSeeingarcsecinstr.obsty.seeingfloatMlimMagnitude limitmagphot.magfloatJ/AJ/106/848/table3bCatalogue of quasar companionsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintQSOQuasar namemeta.id;meta.mainchardRARigth ascension offset from the quasararcsecpos.eq.ra;arith.difffloatdDEDeclination offset from the quasararcsecpos.eq.dec;arith.difffloatDistDistance from the quasararcsecpos.angDistancefloatcls[fgs ] Classification (f: faint, g: galaxy, s: star)meta.code.class;src.class.structcharRmagApparent R magnitude, m(R)magphot.mag;em.opt.Rfloate_RmagFormal photometry error in the magnitudemagstat.error;phot.mag;em.opt.RfloatPAPosition angle of the object with respect to the quasar, measured anti-clockwise from Northdegpos.posAngfloat