J/A+A/618/A59ivo://CDS.VizieR/J/A+A/618/A59doi:10.26093/cds/vizier.36180059CDSCastro-Ginard A.Jordi C.Luri X.Julbe F.Morvan M.Balaguer-Nunez L.,Cantat-Gaudin T.2020-06-02T15:11:56Z2019-06-18T10:06:27ZCDS support team

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

cds-question@unistra.frmilky-way-galaxygalactic-centeropen-star-clustersThe publication of the Gaia Data Release 2 (Gaia DR2) opens a new era in astronomy. It includes precise astrometric data (positions, proper motions, and parallaxes) for more than 1.3 billion sources, mostly stars. To analyse such a vast amount of new data, the use of data-mining techniques and machine-learning algorithms is mandatory. A great example of the application of such techniques and algorithms is the search for open clusters (OCs), groups of stars that were born and move together, located in the disc. Our aim is to develop a method to automatically explore the data space, requiring minimal manual intervention. We explore the performance of a density-based clustering algorithm, DBSCAN, to find clusters in the data together with a supervised learning method such as an artificial neural network (ANN) to automatically distinguish between real OCs and statistical clusters. The development and implementation of this method in a five-dimensional space (l, b, p, {mu}_{alpha}_^*^, {mu}_{delta}_) with the Tycho-Gaia Astrometric Solution (TGAS) data, and a posterior validation using Gaia DR2 data, lead to the proposal of a set of new nearby OCs. We have developed a method to find OCs in astrometric data, designed to be applied to the full Gaia DR2 archive.2018A&A...618A..59Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/618/A59CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/345 : Gaia DR2 (Gaia Collaboration, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/618/A59https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/618/A59http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/618/A59https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/618/A59https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/618/A59http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/618/A59GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/618/A59/members (Members for the reported UBC clusters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/618/A59/members?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/618/A59/members?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/618/A59/members?GETtext/xml+votable180.050000true287.89323191953356.4444932358190.005555555555555556Cone search capability for table J/A+A/618/A59/centers (Mean parameters for the reported UBC clusters (table2 of the paper))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/618/A59/centers?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/618/A59/centers?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/618/A59/centers?GETtext/xml+votable180.050000true287.99827451545256.8334965783130.0055555555555555565/299-300 302-303 389 478 3533 3803 3806 3936 5496 5714-5715 5720-5721 7289 7617 8030 9887 10129 10131 10219 6/511 853 1179 1182 1189 1194 1204 1206 1258 1536 1541 1552-1553 1555 1564-1565 1600 1883 1903 1905 1907-1908 2000-2002 2766-2767 2784-2785 2787 14131 14137 14140 15228 15485 15487 15572-15574 15657-15660 15662 15748 15752 21764 21919 21941 21943 21962 21989 21991 21993 21995-21996 22002 22805 22807 22813 22815 22849-22851 22854-22855 22872 22874 22889 22892 29153 29155 29161 29164-29165 29167 29170-29171 29176-29178 30127 30138 30480 30482-30483 30486 30488-30489 30492 30681 30683-30684 30686 30705 30708 32005 32016 32109 32111 32124 32126 32197 32238 32576-32577 32579-32580 32582 39541-39543 39545 39637 39720 40530 40536 40538 40548-40549 40560 40870 40873 41423 41429 41432-41434 41436-41438 41444-41445 41457 42114 42120 42511 42521-42523 42526 42532-42533 425441.9867573869263685e-19 4.851276835901009e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/618/A59?format=asciidefaultJ/A+A/618/A59/membersMembers for the reported UBC clustersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClusterCluster name (UBCNN_a)meta.id.parentcharSourceGaia DR2 source_idmeta.id;meta.mainGLONGalactic longitude meandegpos.galactic.lonGLATGalactic latitude meandegpos.galactic.latPlxParallax meanmaspos.parallax;stat.meandoublepmRA*Proper motion in right ascension (pmRA*cosDE)mas/yrpos.pm;pos.eq.radoublepmDEProper motion in declinationmas/yrpos.pm;pos.eq.decdoubleGmagGaia G magnitude magnitudemagphot.mag;em.optdoubleBPmag? Gaia BP magnitudemagphot.mag;em.opt.BdoublenullableRPmag? Gaia RP magnitudemagphot.mag;em.opt.RdoublenullableSimbadSimbad column added by the CDSmeta.ref.urlchar_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.decnullableindexedJ/A+A/618/A59/centersMean parameters for the reported UBC clusters (table2 of the paper)NNumber of members foundmeta.numberintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClusterCluster name (UBCNN_a) (UBC1-UBC32)meta.id.parentcharGLONGalactic longitude meandegpos.galactic.lone_GLONGalactic longitude standard deviationdegstat.errordoubleGLATGalactic latitude meandegpos.galactic.late_GLATGalactic latitude standard deviationdegstat.errordoublePlxParallax meanmaspos.parallax;stat.meandoublee_PlxParallax standard deviationmasstat.error;pos.parallaxdoublepmRA*Proper motion in right ascension mean (pmRA*cosDE)mas/yrpos.pm;pos.eq.radoublee_pmRA*Proper motion in right ascension standard deviationmas/yrstat.error;pos.pm;pos.eq.radoublepmDEProper motion in declination meanmas/yrpos.pm;pos.eq.decdoublee_pmDEProper motion in declination standard deviationmas/yrstat.error;pos.pm;pos.eq.decfloatRV? Radial velocitykm/sphys.veloc;pos.heliocentricfloatnullablee_RV? rms uncertainty on RVkm/sstat.errorfloatnullableNRVNumber of members used to compute mean radial velocitymeta.numberintSimbadSimbad column added by the CDSmeta.ref.urlchar_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.decnullableindexed