J/MNRAS/490/157ivo://CDS.VizieR/J/MNRAS/490/157doi:10.26093/cds/vizier.74900157CDSMarchetti T.Rossi E.M.Brown A.G.A.2024-08-20T20:13:33Z2023-02-17T12:40:28ZCDS support team

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

cds-question@unistra.frradial-velocityvisible-astronomytrigonometric-parallaxproper-motionsstellar-distancemilky-way-galaxyWe search for the fastest stars in the subset of stars with radial velocity measurements of the second data release (DR2) of the European Space Agency mission Gaia. Starting from the observed positions, parallaxes, proper motions, and radial velocities, we construct the distance and total velocity distribution of more than 7 million stars in our Milky Way, deriving the full 6D phase space information in Galactocentric coordinates. These information are shared in a catalogue, publicly available at http://home.strw.leidenuniv.nl/~marchetti/research.html. To search for unbound stars, we then focus on stars with a probability greater than 50 per cent of being unbound from the Milky Way. This cut results in a clean sample of 125 sources with reliable astrometric parameters and radial velocities. Of these, 20 stars have probabilities greater than 80 per cent of being unbound from the Galaxy. On this latter subsample, we perform orbit integration to characterize the stars' orbital parameter distributions. As expected given the relatively small sample size of bright stars, we find no hypervelocity star candidates, stars that are moving on orbits consistent with coming from the Galactic Centre. Instead, we find seven hyperrunaway star candidates, coming from the Galactic disc. Surprisingly, the remaining 13 unbound stars cannot be traced back to the Galaxy, including two of the fastest stars (around 700km/s). If conformed, these may constitute the tip of the iceberg of a large extragalactic population or the extreme velocity tail of stellar streams.2019MNRAS.490..157Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/490/157CatalogResearchIsServedByTAP 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/MNRAS/490/157https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/490/157http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/490/157https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/490/157https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/490/157http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/490/157GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/490/157/table2 (Observed and derived properties for the 20 'clean' high-velocity star candidates with a probability >80% of being unbound from the Galaxy)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/490/157/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/490/157/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/490/157/table2?GETtext/xml+votable180.050000true244.1181-54.440450.005555555555555556Cone search capability for table J/MNRAS/490/157/tablec1 (Distances and total velocities in the Galactic rest frame for the 105 'clean' high-velocity star candidates with 0.5<P_ub_=<0.8)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/490/157/tablec1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/490/157/tablec1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/490/157/tablec1?GETtext/xml+votable180.050000true117.2789978-17.08500940.0055555555555555566/8469 9009 9461 9472 9695 9828 9926 11458 12055 13886 13903 13970 14138 14143 14174 14212 14480 14486 14525 14535 14722 14825 14850 14881 14887-14888 14913 14967 15008 15076 15340 15516 15538 16023 24542 26331 26893 27650 27752 28942 29328 29916 29989 30744 31023 31231 31639 31899 32198 32204 32660 32755 33089 34931 37039 37074 37168 37179 37227 37264 37284 37286-37287 37302 37354 37648 37681 37686 37728 37777 37781 37784-37785 37809 38043 38100 38185 38369 38477 39158 39413 39741 39988 40633 41065 41068 41107 41230 41262 41344 41377 41425 41436 41493 41542 41610 41902 42013 42150 42176 42610 42705 42876 42882 43184 43331 43460 43562 44205 44260 44347 45456 45699 45789 45876 46131 46192 47176 47195 47449 47606 47841 488031.9867573869263685e-19 3.916500758235022e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/490/157?format=asciiOpticaldefaultJ/MNRAS/490/157/table2Observed and derived properties for the 20 'clean' high-velocity star candidates with a probability >80% of being unbound from the GalaxyrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSimbadSimbad column added by the CDSmeta.ref.urlchare_pmDEError on pmDEmas/yrstat.error;pos.pm;pos.eq.decfloatRVGaia DR2 radial velocitykm/sphys.veloc;pos.heliocentricdoubleGaiaDR2Gaia DR2 object identifiermeta.id;meta.mainprimaryf_GaiaDR2[eg] Flag on GaiaDR2 (1)meta.codecharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainplxGaia DR2 parallaxmaspos.parallax.trigfloate_plxError on plxmasstat.error;pos.parallaxfloatpmRAGaia DR2 proper motion in right ascensionmas/yrpos.pm;pos.eq.rafloate_pmRAError on pmRAmas/yrstat.error;pos.pm;pos.eq.rafloatpmDEGaia DR2 proper motion in declinationmas/yrpos.pm;pos.eq.decfloate_RVError on RVkm/sstat.errorfloatGmagGaia DR2 G-band magnitudemagphot.mag;em.optfloatdDistancepcpos.distanceintE_dUpper error on dpcstat.error;stat.maxinte_dLower error on dpcstat.errorintrGCGalactocentric distancepcpos.distance;pos.galactocentricintE_rGCUpper error on rGCpcstat.error;stat.maxinte_rGCLower error on rGCpcstat.errorintvGCTotal velocity in the galactic rest framekm/sphys.veloc;pos.galactocentricintE_vGCUpper error on vGCkm/sstat.error;stat.maxinte_vGCLower error on vGCkm/sstat.errorintPMWProbability for a star to come from the Milky Way (2)stat.fit.goodnessfloatPubProbability of being unbound from the Galaxy (G1)stat.fit.goodnessfloatMoreStar information in tables d1 and e1meta.ref.urlcharJ/MNRAS/490/157/tablec1Distances and total velocities in the Galactic rest frame for the 105 'clean' high-velocity star candidates with 0.5<P_ub_=<0.8E_dUpper error on dpcstat.error;stat.maxinte_dLower error on dpcstat.errorintvGCTotal velocity in the galactic rest framekm/sphys.veloc;pos.galactocentricintSimbadSimbad column added by the CDSmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaDR2Gaia DR2 object identifiermeta.id;meta.maindDistancepcpos.distanceintE_vGCUpper error on vGCkm/sstat.error;stat.maxinte_vGCLower error on vGCkm/sstat.errorintPubProbability of being unbound from the Galaxy (G1)stat.fit.goodnessfloat_RAPosition from Gaia DR2 (Gaia Collaboration, 2018, Cat. I/345) (right ascension part)degpos.eq.ra;meta.main_DEPosition from Gaia DR2 (Gaia Collaboration, 2018, Cat. I/345) (declination part)degpos.eq.dec;meta.mainJ/MNRAS/490/157/tabled1Distances and total velocities in the Galactic rest frame for the 20 'clean' high-velocity star candidates with P_ub_>0.8 presented in Table 2, including the -0.029mas global parallax offsetdDistancepcpos.distanceintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaDR2Gaia DR2 object identifiermeta.id;meta.mainE_dUpper error on dpcstat.error;stat.maxinte_dLower error on dpcstat.errorintvGCTotal velocity in the galactic rest framekm/sphys.veloc;pos.galactocentricintE_vGCUpper error on vGCkm/sstat.error;stat.maxinte_vGCLower error on vGCkm/sstat.errorintPubProbability of being unbound from the Galaxy (G1)stat.fit.goodnessfloatJ/MNRAS/490/157/tablee1Distances and total velocities in the Galactic rest frame for the 20 'clean' high-velocity star candidates with P_ub_>0.8 presented in Table 2, including systematic errors in parallaxrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaDR2Gaia DR2 object identifiermeta.id;meta.maindDistancepcpos.distanceintE_dUpper error on dpcstat.error;stat.maxinte_dLower error on dpcstat.errorintvGCTotal velocity in the galactic rest framekm/sphys.veloc;pos.galactocentricintE_vGCUpper error on vGCkm/sstat.error;stat.maxinte_vGCLower error on vGCkm/sstat.errorintPubProbability of being unbound from the Galaxy (G1)stat.fit.goodnessfloat