J/MNRAS/466/3088ivo://CDS.VizieR/J/MNRAS/466/3088doi:10.26093/cds/vizier.74663088CDSWilliams P.Agnello A.Treu T.2024-08-17T20:17:52Z2019-11-27T16:21:38ZCDS support team

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

cds-question@unistra.frquasarsgravitational-lensingWide-field photometric surveys enable searches of rare yet interesting objects, such as strongly lensed quasars or quasars with a bright host galaxy. Past searches for lensed quasars based on their optical and near-infrared properties have relied on photometric cuts and spectroscopic preselection (as in the Sloan Quasar Lens Search), or neural networks applied to photometric samples. These methods rely on cuts in morphology and colours, with the risk of losing many interesting objects due to scatter in their population properties, restrictive training sets, systematic uncertainties in catalogue-based magnitudes and survey-to-survey photometric variations. Here, we explore the performance of a Gaussian mixture model to separate point-like quasars, quasars with an extended host and strongly lensed quasars using grizpsf and model magnitudes and WISEW1, W2. The choice of optical magnitudes is due to their presence in all current and upcoming releases of wide-field surveys, whereas UV information is not always available. We then assess the contamination from blue galaxies and the role of additional features such as W3 magnitudes or psf-model terms as morphological information. As a demonstration, we conduct a search in a random 10 per cent of the SDSS footprint, and provide the catalogue of the 43 SDSS object with the highest 'lens' score in our selection that survive visual inspection, and are spectroscopically confirmed to host active nuclei. We inspect archival data and find images of 5/43 objects in the Hubble Legacy Archive, including two known lenses.2017MNRAS.466.3088Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/466/3088CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/466/3088https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/466/3088http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/466/3088https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/466/3088https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/466/3088http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/466/3088GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/466/3088/table2 (List of all known lenses in SDSS, along with selected membership probabilities)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/466/3088/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/466/3088/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/466/3088/table2?GETtext/xml+votable180.050000true4.54744772.94445390.005555555555555556Cone search capability for table J/MNRAS/466/3088/table3 (*Coordinates and colours of the 43 SDSS objects selected by visual inspection.)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/466/3088/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/466/3088/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/466/3088/table3?GETtext/xml+votable180.050000true26.3191345-9.75478430.0055555555555555566/4124 4315 4415 4596 4615 4764 4850 5190 5372 5439 5733 5817 5876 5905 5922 6017 6085 6133 6166 6243 6384 6390 6572 6578 6599 6604 6616 7220 7266 7309 7334 7424 7426 7536 7540 8286 8352 8407 8423 8707 8748 8912 8922 9168 9268 9320 9327 9359 9387 9409 9458 9508 9639 9837 9907 10189 10334 10408 10439 10555 10698 10743 10925 10995 11063-11064 11188 11341 11347 11364 11424 11804 11814 11850 12719 16893 17305 17319 17493 17510 17514 17561 17579 17727 17743 17746 17748 17756 17838 17898 18028 18069 18096 18107 18385 18391 18766 18776 18780-18781 18907 19131 19216 19426 19741 19846 20073 21972 22007 23101 23339 23419 25245 26001 26013-26014 26157 26199 26202 26266 26316 26368 26372 26381 26460 26483 26489 26525 26555 26578 26618 26621 26877 26990 27004 27021 27034 27127 27204 27232 27252 27318 27330 27395 27446-27447 27577 27756 27852 27978 28005 28112 28245 28260 28371 28628 31146 31313 31334 31412 31459 31615 31690 36766 36780 36784 490131.3088508223161842e-20 6.090060298487514e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/466/3088?format=asciidefaultJ/MNRAS/466/3088/table2List of all known lenses in SDSS, along with selected membership probabilitiesNameNamemeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainp(lens)Probability of lensed QSOstat.fit.goodnessdoublep(PLQSO)Probability of point-like QSO, all redshiftsstat.fit.goodnessdoublep(ExtQSO1)Probability of extended QSO, 1.2<z<1.75stat.fit.goodnessdoublep(ExtQSO2)Probability of extended QSO, 1.75<z<2.4stat.fit.goodnessdoublep(ExtQSO3)Probability of extended QSO, z>2.4stat.fit.goodnessdoubleSepSeparationarcsecpos.angDistancefloatSloanDisplay the online SDSS data for this QSOmeta.ref.urlcharJ/MNRAS/466/3088/table3*Coordinates and colours of the 43 SDSS objects selected by visual inspection.SimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Rigth ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainumagSDSS u magnitude (AB)magphot.mag;em.opt.UfloatgmagSDSS g magnitude (AB)magphot.mag;em.opt.BfloatrmagSDSS r magnitude (AB)magphot.mag;em.opt.RfloatimagSDSS i magnitude (AB)magphot.mag;em.opt.IfloatzmagSDSS z magnitude (AB)magphot.mag;em.opt.IfloatW1magWISE W1 magnitude (Vega)magphot.mag;em.IR.3-4umfloatW2magWISE W2 magnitude (Vega)magphot.mag;em.IR.4-8umfloatgmagpsfSDSS PSF g magnitude (AB)magphot.mag;em.opt.BfloatrmagpsfSDSS PSF r magnitude (AB)magphot.mag;em.opt.RfloatimagpsfSDSS PSF i magnitude (AB)magphot.mag;em.opt.IfloatW3magWISE W3 magnitude (Vega)magphot.flux.density;em.IR.8-15umfloatzRedshiftsrc.redshiftfloatp(lens)Lensing QSO probabilitystat.fit.goodnessdoubleSloanDisplay the online SDSS data for this QSOmeta.ref.urlchar