J/A+A/668/A99ivo://CDS.VizieR/J/A+A/668/A99doi:10.26093/cds/vizier.36680099CDSHughes A.C.N.Bailer-Jones C.A.L.Jamal S.2024-11-06T20:01:57Z2022-12-13T07:58:59ZCDS support team

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

cds-question@unistra.frsurveysquasarsgalaxiesIn this work, we assess the combined use of Gaia photometry and astrometry with infrared data from CatWISE in improving the identification of extragalactic sources compared to the classification obtained using Gaia data. Here we perform a comprehensive study in which we assess different input feature configurations and prior functions to identify extragalactic sources in Gaia, with the aim of presenting a classification methodology that integrates prior knowledge stemming from realistic class distributions in the Universe. In our work, we compare different classifiers, namely Gaussian mixture models (GMMs) and the boosted decision trees, XGBoost and CatBoost, in a supervised approach, and classify sources into three classes, namely star, quasar, and galaxy, with the target quasar and galaxy class labels obtained from the Sloan Digital Sky Survey Data release 16 (SDSS16) and the star label from Gaia EDR3. In our approach, we adjust the posterior probabilities to reflect the intrinsic distribution of extragalactic sources in the Universe via a prior function. In particular, we introduce two priors, a global prior reflecting the overall rarity of quasars and galaxies, and a mixed prior that incorporates in addition the distribution of the extragalactic sources as a function of Galactic latitude and magnitude. Our best classification performances, in terms of completeness and purity of the extragalactic classes, namely the galaxy and quasar classes, are achieved using the mixed prior for sources at high latitudes and in the magnitude range G=18.5-19.5. We apply our identified best-performing classifier to three application datasets from Gaia Data Release 3 (GDR3), and find that the global prior is more conservative in what it considers to be a quasar or a galaxy compared to the mixed prior. In particular, when applied to the quasar and galaxy candidate tables from GDR3, the classifier using a global prior achieves purities of 55% for quasars and 93% for galaxies, and purities of 59% and 91%, respectively, using the mixed prior. When compared to the performances obtained on the GDR3 pure quasar and galaxy candidate samples, we reach a higher level of purity, 97% for quasars and 99.9% for galaxies using the global prior, and purities of 96% and 99%, respectively, using the mixed prior. When refining the GDR3 candidate tables via a cross-match with SDSS DR16 confirmed quasars and galaxies, the classifier reaches purities of 99.8% for quasars and 99.9% for galaxies using a global prior, and 99.9% and 99.9% using the mixed prior. We conclude our work by discussing the importance of applying adjusted priors that portray realistic class distributions in the Universe and the effect of introducing infrared data as ancillary inputs in the identification of extragalactic sources.2022A&A...668A..99Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/668/A99CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)I/356 : Gaia DR3 Part 2. Extra-galactic (Gaia Collaboration, 2022)II/365 : The CatWISE2020 catalog (updated version 28-Jan-2021) (Marocco+, 2021)V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/668/A99https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/668/A99http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/668/A99https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/668/A99https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/668/A99http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/668/A99GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/668/A99/quasarpb (Probabilities on the GDR3 quasar candidate table)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/668/A99/quasarpb?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/668/A99/quasarpb?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/668/A99/quasarpb?GETtext/xml+votable180.050000true45.07550470.15231610.005555555555555556Cone search capability for table J/A+A/668/A99/galaxypb (Probabilities on the GDR3 galaxy candidate table)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/668/A99/galaxypb?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/668/A99/galaxypb?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/668/A99/galaxypb?GETtext/xml+votable180.050000true223.1049083-51.42940030.0055555555555555560/1-2 4 6 8 11 1/0 2 12-14 20-22 30-31 37 39 42-43 2/5 7 13-15 62-63 93 112-114 116-117 119 144-146 152 154-155 160-162 164 166 3/17-19 24-26 48 50-51 240 242-244 246-247 368-370 376-378 381-383 460 462 474 588-590 612 614-615 652 654-655 660-662 668-670 4/64 66-67 108 110-111 196 198-199 964-965 967 980-981 983 1484-1486 1516-1518 1521-1523 1845 1847 1853-1855 1888-1890 1892-1893 1895 1900 1902-1903 2364 2366-2367 2452 2454 2613-2615 2652 2654-2655 2684-2685 2687 5/260-261 436-438 789-791 3865-3867 3929-3931 5948 5950-5951 6077-6082 7377-7379 7384-7386 7408 7410-7411 7565-7566 7576-7577 7605-7607 9461-9463 9812-9813 9815 9821-9823 10448-10449 10451 10612-10613 10744 10746-10747 6/1048-1049 1051-1053 1055 1756-1757 1759 3152-3154 15456 15458-15459 15712 15714-15715 23797-23798 24304-24306 24332 24334-24335 29505-29507 29548-29550 29636 29638-29639 30256 30258-30259 30269-30271 30312-30313 30315-30317 30319 30416-30418 37840-37841 37843 39257-39259 39281-39283 41800-41802 42456-42458 42461-42463 42980-42982https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/668/A99?format=asciidefaultJ/A+A/668/A99/quasarpbProbabilities on the GDR3 quasar candidate tablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaDR3Gaia-DR3 identification number (source_id)meta.id;meta.mainisQSOpure[F/T] Binary flag indicating in the GDR3 pure quasar sample (isQSO_pure)meta.codecharisQSOSDSS[F/T] Binary flag indicating in the SDSS16 quasar sample (isQSO_pure)meta.codecharpStarStar probability (pStar)stat.fit.goodnessdoublepQSOQuasar probability (pQSO)stat.fit.goodnessdoublepGALGalaxy probability (pGAL)stat.fit.goodnessdouble_RAPositions from Gaia DR3 (right ascension part)degpos.eq.ra;meta.mainindexed_DEPositions from Gaia DR3 (declination part)degpos.eq.dec;meta.mainindexedJ/A+A/668/A99/galaxypbProbabilities on the GDR3 galaxy candidate tablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaDR3Gaia-DR3 identification number (source_id)meta.id;meta.mainisGALpure[F/T] Binary flag indicating in the GDR3 pure galaxy sample (isGAL_pure)meta.codecharisGALSDSS[F/T] Binary flag indicating in the SDSS16 galaxy sample (isGAL_SDSS)meta.codecharpStarStar probability (pStar)stat.fit.goodnessdoublepQSOQuasar probability (pQSO)stat.fit.goodnessdoublepGALGalaxy probability (pGAL)stat.fit.goodnessdouble_RAPositions from Gaia DR3 (right ascension part)degpos.eq.ra;meta.mainindexed_DEPositions from Gaia DR3 (declination part)degpos.eq.dec;meta.mainindexed