J/A+A/710/A180ivo://CDS.VizieR/J/A+A/710/A180CDSWu D.He Z.Li N.Cui S.Fu Y.Wu X.-B.Qiu D.Jiang S.2026-06-10T11:50:17Z2026-06-10T12:48:46ZCDS support team

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

cds-question@unistra.frquasarsgravitational-lensinggalaxy-clustersvisible-astronomyWide-separation lensed quasars (WSLQs) represent a special but rare subclass of strongly lensed quasars with multiple images, magnified by massive galaxy cluster lenses, which offer valuable probes for the properties of dark matter halos and detailed characteristics of quasar host galaxies. However, only around ten WSLQ systems are known so far, limiting the development of relevant investigations. To enlarge the sample of WSLQs by mining candidates from large-scale sky surveys, we develop a catalogue-based pipeline and apply it to the CatNorth, which is a quasar candidate catalogue with more than 1.5 million candidates constructed from Gaia DR3. The CatNorth has a purity of ~90% and a limiting magnitude in the Gaia G band of <~21. Our pipeline unfolds in three sequential stages. First, to search for groups of quasar candidates with a maximum quasar image separation between 10 and 72 arcsec, we applied a friends-of-friends-like algorithm to the HEALPix grids of CatNorth objects using a grid size of 25.6 arcsec. Second, these identified groups undergo an automatic filtering process that assesses the intra-group similarity of photometric colours or spectral information when available. These two steps yield 14 760 quasar candidate groups, while retaining all discoverable previously known WSLQs. Third, a visual inspection, guided primarily by the projected geometry of the quasar images and plausible foreground objects, yields the final candidate sample, with a label indicating the candidates' quality. We have identified a total of 333 new WSLQ candidates with separations ranging from 10 to 56.8 arcsec. By exploiting the available SDSS DR16/DESI DR1 spectroscopic data, we uncovered two novel WSLQ candidate systems, but 331 WSLQ candidates - 45 Grade A, 98 Grade B, and 188 Grade C systems - lack sufficient spectral information. In addition, a sample of 29 dual quasar candidates is presented as a by-product. When feasible, we plan to secure follow-up spectroscopy and deeper imaging to confirm WSLQs from the above candidates and proceed with pertinent scientific investigations.2026A&A...710A.180Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/710/A180CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/365 : The CatWISE2020 catalog (28-Jan-2021 version) (Marocco+, 2021)I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)II/349 : The Pan-STARRS release 1 (PS1) Survey - DR1 (Chambers+, 2016)J/ApJS/199/34 : Clusters of galaxies in SDSS-III (Wen+, 2012)J/ApJ/807/178 : Newly rich galaxy clusters identified in SDSS-DR12 (Wen+, 2015)J/ApJS/253/56 : Galaxy clusters from the DESI surveys. I. (Zou+, 2021)J/ApJS/271/54 : CatNorth: improved GaiaDR3 quasar cat. with PS1 + WISEhttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/710/A180https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/710/A180http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/710/A180https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/710/A180https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/710/A180http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/710/A180GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/710/A180/wslq (Wide-separation lensed quasar candidate members (table C1))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/710/A180/wslq?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/710/A180/wslq?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/710/A180/wslq?GETtext/xml+votable180.050000true253.4701007238.761699360.005555555555555556Cone search capability for table J/A+A/710/A180/dqso (Dual-QSO candidate members (table C2))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/710/A180/dqso?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/710/A180/dqso?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/710/A180/dqso?GETtext/xml+votable180.050000true219.2898509838.212153360.0055555555555555566/175 211 568 939 2062 2157 2163 2690 2702 3539 4244 4346 4422 4442 4469 4489 4554 4598 4716 4769 4819 4858 4867 4919 5028 5065 5202 5319-5320 5328 5356 5358 5375 5442 5450 5471 5687 5694 5697 5764 5766 5772 5980 6072 6135 6441 6466 6853 6920 7003 7119 7380 7488 7502 7534 7551 7582 7621 7776 7799 7807 7832 7881 7886 7959 7973 7981 8027 8346 8359 8610 8681 8712 8737 8756 8795 8807 8824 8829 8862 8879 9056-9057 9095 9189 9200 9213 9235 9354 9385 9412 9454 9525 9532 9606 9634 9676 9779 10146 10290 10317 10377 10389 10435 10563 10566 10572-10573 10587 10595 10672 10713 10813 10819 10836 10908 10924 11011 11071 11106 11195 11495 11505 11582 11594 11615 11642 11652 11681 11811 11863 11917 11925 11942 12053 12105 12121 12189 12195 12232 12326 13340 13388 13401 14881 14888 14995 15281 15321 15913 16033 16066 16077 16105 16107 16453 16462 16532 16571 16619 16650 16711 16888 16926 17057 17099 17168 17273 17298 17356 17441 17444 17457 17460 17479 17698 17704 17909 18059 18419 18448 18516 18533 18571 18640 18880 18892 18953 19321 19604 19753 19828 20164 20172 20260 20281 20425 20434 20464 20874 20887 21019 21032 21098 21122 21785 21815 21865 22563 22569 22617 22891 23022 23049 23075 23114 23197 24289 24669 24827 24843 24879 24894 24923 24925 24988 25114 25273 25284 25318 25339 25392 25465 25479 25511 25522 25643 25647 25700 25828 26025 26367 26375 26485 26536 26651-26652 26722 26788 26899 26906 27073 27111 27371 27482 27503 27554 27606 27737 27757 27966 28068 28075 28100 28158 28245 28313 28427 28447 28480 28520 28592 28620 28648-28649 28663 31442 31449 32296 32422 32471 32562 32639 32669-32670 32685 32731 32750 34546 34557 34629 34664 34685 34705 34707 34714 34752 34761 34783 34793 35649 35680 35687 35727 35814 35942 35976-35977 35999 36022 36064 36072 36105 36120 36132 36135 36137 36193 36210 36232 36258 36337 36364 36367 36425 36436 36502 36516 36530 36587 36597 36600 36616 36681 36760 36819 38876 38888 38898 39662 39673 40304 40801 43806 43891 44257 44261 44420 44516 44628 44678 44707 44828 46907 46981 46992 46994 47087 48209 48395 48476 48868 490961.9867573869263685e-19 3.916500758235022e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/710/A180?format=asciiOpticaldefaultJ/A+A/710/A180/wslqWide-separation lensed quasar candidate members (table C1)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGroupIdCandidate system identifiermeta.id;pos.framelonge_pmDE? Uncertainty in pmDEmas/yrstat.error;pos.pm;pos.eq.decfloatnullable_RA.icrsRight ascension (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.raindexed_DE.icrsDeclination (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.decindexedRA_ICRSGaia DR3 right ascension (ICRS) at Ep=2016.0degpos.eq.ra;meta.mainDE_ICRSGaia DR3 declination (ICRS) at Ep=2016.0degpos.eq.dec;meta.mainsepMaxMaximum angular separation in systemarcsecpos.angDistance;stat.maxdoublezdiffMaximum photometric-redshift differencesrc.redshift;arith.diffdoubleqsoNumNumber of quasar-candidate membersmeta.numberfloatScol? Colour-similarity statisticstat.fit.paramdoublenullableRAWdeg? Right ascension of matched WEN BCGdegpos.eq.ranullableDEWdeg? Declination of matched WEN BCGdegpos.eq.decnullablezW? Cluster redshift in WEN_CATsrc.redshift;pos.heliocentricdoublenullableM500W? Cluster M500 in WEN_CAT (1)1e+14solMassphys.massfloatnullableIDWenCat? Cluster identifier in WEN_CATmeta.idintnullableRAZdeg? Right ascension of matched ZOU BCGdegpos.eq.ranullableDEZdeg? Declination of matched ZOU BCGdegpos.eq.decnullablezZ? Cluster redshift in ZOU_CATsrc.redshift;pos.heliocentricdoublenullablelogM500Z? log10(cluster M500) in ZOU_CAT (1)log(solMass)phys.massdoublenullableIDZouCat? Cluster identifier in ZOU_CATmeta.idnullableRAXdeg? Right ascension of matched eROSITA cl.degpos.eq.ranullableDEXdeg? Declination of matched eROSITA cl.degpos.eq.decnullablezeRos? Cluster redshift in eROSITA cataloguesrc.redshift;pos.heliocentricfloatnullableM500eRos? Cluster M500 in eROSITA cat. (1)1e+13solMassphys.massfloatnullableIDeRosCatCluster identifier in eROSITA cat.meta.idcharGaiaDR3Gaia DR3 source identifiermeta.idGLONGalactic longitudedegpos.galactic.lonGLATGalactic latitudedegpos.galactic.latdoublePlx? Gaia parallaxmaspos.parallaxfloatnullablee_Plx? Parallax uncertaintymasstat.error;pos.parallaxfloatnullablepmRA? Proper motion in right ascensionmas/yrpos.pm;pos.eq.rafloatnullablee_pmRA? Uncertainty in pmRAmas/yrstat.error;pos.pm;pos.eq.rafloatnullablepmDE? Proper motion in declinationmas/yrpos.pm;pos.eq.decfloatnullablepmCorr? pmRA-pmDE correlation coefficientstat.correlationfloatnullableBPmagGaia BP mean magnitudemagphot.mag;em.opt.BdoubleGmagGaia G mean magnitudemagphot.mag;em.optdoubleRPmagGaia RP mean magnitudemagphot.mag;em.opt.RdoubleBP-RPGaia BP-RP colourmagphot.color;em.opt.B;em.opt.RdoubleE(BP/RP)Gaia BP/RP excess factormagphot.color.excessdoublePS1Pan-STARRS1 identifiermeta.idRAPdegPan-STARRS1 right ascensiondegpos.eq.raDEPdegPan-STARRS1 declinationdegpos.eq.decgmag? Pan-STARRS1 g magnitudemagphot.mag;em.opt.Bdoublenullablee_gmag? Uncertainty in gmagmagstat.error;phot.magdoublenullablermag? Pan-STARRS1 r magnitudemagphot.mag;em.opt.Rdoublenullablee_rmag? Uncertainty in rmagmagstat.error;phot.magdoublenullableimagPan-STARRS1 i magnitudemagphot.mag;em.opt.Idoublee_imagUncertainty in imagmagstat.error;phot.magdoublezmag? Pan-STARRS1 z magnitudemagphot.mag;em.opt.Idoublenullablee_zmag? Uncertainty in zmagmagstat.error;phot.magdoublenullableymag? Pan-STARRS1 y magnitudemagphot.mag;em.IR.Jdoublenullablee_ymag? Uncertainty in ymagmagstat.error;phot.magdoublenullableCatWISECatWISE2020 identifiermeta.idcharRACdegCatWISE2020 right ascensiondegpos.eq.raDECdegCatWISE2020 declinationdegpos.eq.decpmRAcatCatWISE2020 pmRAmas/yrpos.pm;pos.eq.radoublepmDEcatCatWISE2020 pmDEmas/yrpos.pm;pos.eq.decdoublee_pmRAcatUncertainty in pmRAcatmas/yrstat.error;pos.pm;pos.eq.radoublee_pmDEcatUncertainty in pmDEcatmas/yrstat.error;pos.pm;pos.eq.decdoublesnrW1pmS/N in W1 proper-motion fitstat.snrfloatsnrW2pmS/N in W2 proper-motion fitstat.snrfloatW1magCatWISE2020 W1 magnitudemagphot.mag;em.IR.3-4umdoublee_W1magUncertainty in W1magmagstat.error;phot.magdoubleW2magCatWISE2020 W2 magnitudemagphot.mag;em.IR.4-8umdoublee_W2magUncertainty in W2magmagstat.error;phot.magdoublechi2pmRA? chi-square of pmRAcat fitmeta.notefloatnullablechi2pmDE? chi-square of pmDEcat fitmeta.notefloatnullableE(BP/RP)CCorrected BP/RP excess factormagphot.color.excessdoublefpm0? Feature fpm0 from CatNorthstat.fit.goodnessdoublenullablelogfpm0Logarithm of fpm0stat.fit.goodnessdoublepGalMeanMean galaxy probabilitystat.fit.goodnessdoublepQsoMeanMean quasar probabilitystat.fit.goodnessdoublepStarMeanMean stellar probabilitystat.fit.goodnessdoublezGaia? Gaia-based redshift estimatesrc.redshift;pos.heliocentricdoublenullablezphXGBPhotometric redshift from XGB modelsrc.redshift;pos.heliocentricdoublezphTabTabulated photometric redshiftsrc.redshift;pos.heliocentricdoublezphFTTPhotometric redshift from FTT methodsrc.redshift;pos.heliocentricdoublezphAdopted photometric redshiftsrc.redshiftdoublezxpNN? XP-neural-network redshiftsrc.redshift;pos.heliocentricdoublenullableps1GoodFlag for reliable PS1 photometrymeta.codecharGradeVisual-inspection grade (A, B, or C)meta.notecharJ/A+A/710/A180/dqsoDual-QSO candidate members (table C2)RA_ICRSGaia DR3 right ascension (ICRS) at Ep=2016.0degpos.eq.ra;meta.mainDE_ICRSGaia DR3 declination (ICRS) at Ep=2016.0degpos.eq.dec;meta.mainpmDEcatCatWISE2020 pmDE (from CatNorth)mas/yrpos.pm;pos.eq.decdoublee_pmRAcatUncertainty in pmRACat (from CatNorth)mas/yrstat.error;pos.pm;pos.eq.rafloate_pmDEcatUncertainty in pmDECat (from CatNorth)mas/yrstat.error;pos.pm;pos.eq.decdoublesnrW1pmS/N in W1 proper-motion fit (from CatNorth)stat.snrfloatsnrW2pmS/N in W2 proper-motion fit (from CatNorth)stat.snrfloat_RA.icrsRight ascension (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.raindexed_DE.icrsDeclination (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.decindexedrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGroupIdCandidate dual-QSO system identifiermeta.id;pos.framelongdVVelocity difference between the two quasar candidateskm/sphys.veloc;arith.diffdoublesepMaxAngular separation between the two quasar candidatesarcsecpos.angDistancedoubleDprojProjected physical separation between the two quasar candidateskpcpos.distancedoubleRAWdeg? Right ascension of the matched BCG in WEN_CAT (WenBCGRA)degpos.eq.ranullableDEWdeg? Declination of the matched BCG in WEN_CAT (WenBCGDE)degpos.eq.decnullablezW? Cluster redshift in WEN_CATsrc.redshift;pos.heliocentricfloatnullableM500W? Cluster M500 in WEN_CAT, in units of 10^14^ solar masses1e+14solMassphys.massfloatnullableIDWenCat? Cluster identifier in WEN_CATmeta.iddoublenullableGaiaDR3Gaia DR3 source identifier (from CatNorth)meta.idGLONGalactic longitude (from CatNorth)degpos.galactic.lonGLATGalactic latitude (from CatNorth)degpos.galactic.latdoublePlxGaia parallax (from CatNorth)maspos.parallaxfloate_PlxParallax uncertainty (from CatNorth)masstat.error;pos.parallaxfloatpmRAProper motion in right ascension (from CatNorth)mas/yrpos.pm;pos.eq.rafloate_pmRAUncertainty in pmRA (from CatNorth)mas/yrstat.error;pos.pm;pos.eq.rafloatpmDEProper motion in declination (from CatNorth)mas/yrpos.pm;pos.eq.decfloate_pmDEUncertainty in pmDE (from CatNorth)mas/yrstat.error;pos.pm;pos.eq.decfloatpmCorrpmRA-pmDE correlation coefficient (from CatNorth)stat.correlationfloatBPmagGaia BP mean magnitude (from CatNorth)magphot.mag;em.opt.BfloatGmagGaia G mean magnitude (from CatNorth)magphot.mag;em.optfloatRPmagGaia RP mean magnitude (from CatNorth)magphot.mag;em.opt.RfloatBP-RPGaia BP-RP colour (from CatNorth)magphot.color;em.opt.B;em.opt.RfloatE(BP/RP)Gaia BP/RP excess factor (from CatNorth)magphot.color.excessfloatPS1Pan-STARRS1 identifier (from CatNorth)meta.idRAPdegPan-STARRS1 right ascension (from CatNorth)degpos.eq.raDEPdegPan-STARRS1 declination (from CatNorth)degpos.eq.decgmagPan-STARRS1 g magnitude (from CatNorth)magphot.mag;em.opt.Bdoublee_gmagUncertainty in gmag (from CatNorth)magstat.error;phot.magdoublermagPan-STARRS1 r magnitude (from CatNorth)magphot.mag;em.opt.Rdoublee_rmagUncertainty in rmag (from CatNorth)magstat.error;phot.magdoubleimagPan-STARRS1 i magnitude (from CatNorth)magphot.mag;em.opt.Idoublee_imagUncertainty in imag (from CatNorth)magstat.error;phot.magdoublezmagPan-STARRS1 z magnitude (from CatNorth)magphot.mag;em.opt.Idoublee_zmagUncertainty in zmag (from CatNorth)magstat.error;phot.magdoubleymag? Pan-STARRS1 y magnitude (from CatNorth)magphot.mag;em.IR.Jdoublenullablee_ymag? Uncertainty in ymag (from CatNorth)magstat.error;phot.magdoublenullableCatWISECatWISE2020 identifier (from CatNorth)meta.idcharRACdegCatWISE2020 right ascension (from CatNorth)degpos.eq.raDECdegCatWISE2020 declination (from CatNorth)degpos.eq.decpmRAcatCatWISE2020 pmRA (from CatNorth)mas/yrpos.pm;pos.eq.radoubleW1magCatWISE2020 W1 magnitude (from CatNorth)magphot.mag;em.IR.3-4umdoublee_W1magUncertainty in W1mag (from CatNorth)magstat.error;phot.magdoubleW2magCatWISE2020 W2 magnitude (from CatNorth)magphot.mag;em.IR.4-8umdoublee_W2magUncertainty in W2mag (from CatNorth)magstat.error;phot.magdoublechi2pmRAChi-square of pmRACat fit (from CatNorth)meta.notefloatchi2pmDEChi-square of pmDECat fit (from CatNorth)meta.notefloatE(BP/RP)CCorrected BP/RP excess factor (from CatNorth)magphot.color.excessdoublefpm0Feature fpm0 from CatNorthstat.fit.goodnessdoublelogfpm0Logarithm of fpm0 (from CatNorth)stat.fit.goodnessdoublepGalMeanMean galaxy probability (from CatNorth)stat.fit.goodnessdoublepQsoMeanMean quasar probability (from CatNorth)stat.fit.goodnessdoublepStarMeanMean stellar probability (from CatNorth)stat.fit.goodnessfloatzGaia? Gaia-based redshift estimate (from CatNorth)src.redshift;pos.heliocentricdoublenullablezphXGBPhotometric redshift from XGB model (from CatNorth)src.redshift;pos.heliocentricfloatzphTabTabulated photometric redshift (from CatNorth)src.redshift;pos.heliocentricfloatzphFTTPhotometric redshift from FTT method (from CatNorth)src.redshift;pos.heliocentricdoublezphAdopted photometric redshift (from CatNorth)src.redshiftfloatzxpNN? XP-neural-network redshift (from CatNorth)src.redshift;pos.heliocentricfloatnullableps1GoodFlag for reliable PS1 photometry (from CatNorth)meta.codecharinJ25Flag indicating whether the system has a counterpart in J25meta.codechar