J/A+A/704/A294ivo://CDS.VizieR/J/A+A/704/A294CDSKatz D.Gomez A.Caffau E.Bonifacio P.Hottier C.Vanel O.,Soubiran C.Panuzzo P.Chosson D.Sartoretti P.Lallement R.,Di Matteo P.Haywood M.Robichon N.Baker S.Barbier A.Bashi D.,Benson K.Blomme R.Brouillet N.Casamiquella L.Chemin L.Cropper M.,Damerdji Y.Dolding C.Faigler S.Fremat Y.Gosset E.Guerrier A.,Haigron R.Huckle H.E.Leclerc N.Lobel A.Marchal O.Mazeh T.,Mints A.Royer F.Seabroke G.M.Smith M.Snaith O.Thevenin F.,Weingrill K.2026-03-02T06:25:50Z2025-12-22T12:37:18ZCDS support team

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

cds-question@unistra.frhigh-velocity-starsradial-velocityeffective-temperaturemetallicityThe third Gaia data release includes 33.8 million radial velocity measurements, extending to a magnitude of G_RVS_=14. To reach this magnitude limit, spectra were processed down to a signal-to-noise ratio (S/N) of 2. In this very low S/N regime, noise-induced peaks in the cross-correlation function can result in spurious radial velocity determinations. Quality filters were applied to the dataset to mitigate such artefacts as much as possible prior to publication. Nevertheless, the high radial velocity (HRV) stars -- defined here as those with radial velocities below -500 or above +500km/s -- are so sparsely populated that even a few hundred spurious measurements can lead to significant contamination. The objectives of the present study are as follows: (i) to confirm or refute the radial velocity values of the order of one hundred Gaia DR3 HRV stars, (ii) to evaluate the rate of spurious radial velocities in the Gaia DR3 catalogue as a function of S/N and radial velocity, and (iii) to examine the properties of the genuine HRV stars. A total of 134 Gaia DR3 HRV stars were observed using the SOPHIE and UVES spectrographs. Their radial velocities were determined via cross-correlation or template-matching methods. These measurements were subsequently combined with radial velocities from the APOGEE, GALAH, GES, LAMOST, and RAVE catalogues in order to assess the rate of erroneous Gaia DR3 radial velocities as a function of S/N and radial velocity range. Finally, the orbits of a clean sample of HRV stars were integrated using an axisymmetric Galactic gravitational potential. Ground-based measurements confirm the Gaia DR3 radial velocities of 104 out of our 134 targets, and they refute those of the remaining 30. The combination of these data with the spectroscopic surveys mentioned above enabled an assessment of the rate of spurious measurements as a function of S/N and across three intervals of absolute value of the radial velocity: [0, 200), [200, 400), and [400, 1000)km/s. The outlier rate reaches up to 83% in the S/N range [2, 3) and velocity interval [400, 1000)km/s, and it decreases rapidly with increasing S/N and/or with decreasing absolute value of the radial velocity. The confirmed radial velocities were then combined with Gaia DR3 HRV stars having S/N>10, in order to construct a clean sample of HRV stars. The majority of these stars follow retrograde orbits. Their location in the energy-vertical component of the angular momentum diagram coincides with the region where several structures associated with past merging events have been identified: Sequoia, Arjuna and I'itoi, Antaeus, ED-2, and ED-3. It is likely that most of these HRV stars were accreted.2025A&A...704A.294Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/704/A294CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)J/A+A/651/A20 : Gaia RVS benchmark stars. I. (Caffau+, 2021)J/A+A/683/A72 : Gaia RVS benchmark stars. II. (Caffau+, 2024)J/AN/346/70025 : Gaia RVS benchmark stars. III. (Caffau+, 2025)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/704/A294https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/704/A294http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/704/A294https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/704/A294https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/704/A294http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/704/A294GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/704/A294/tablea1 (Coordinates and radial velocities)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/704/A294/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/704/A294/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/704/A294/tablea1?GETtext/xml+votable180.050000true46.907237.29150.0055555555555555566/990 1332 2420 2441 2696 6727 8779 9488 9495 9559 9619 10045 10090 10099 11505 11627 12446 12518 12527 12563 12591 12609 12612 12621 12638 12713 12816 12891 13069 13071 13243 13335 13552 13881 14054 14097 14155 14452 14481 14545 14890 15243 15369 15378 15621 15832 17641 18603 18962 19109 19169 19177 19375 19409 20118 20758 21079 21685 21776 21806 21820 22217 22255 22502 23964 24339 25189 25386 25476 25894 26845 26857 27216 27787 28763 28795 29039 29623 29844 29882 29898 29980 30103 30105 30173 30204 30298 30473 30496 31508 31979 32048 32205 32454 32582 32730 32744 32957 34258 37080 37840 38047 38073 38124 38160 38177 38247 38349 38477 38583 38586 38707 39190 40087 40089 40094 40174 40237 40628 40674 40911 41151 41237 41254 41259 41523 41638 42152 43157 43360 43367 43690 45605 457281.9867573869263685e-19 3.916500758235022e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/704/A294?format=asciidefaultJ/A+A/704/A294/tablea1Coordinates and radial velocitiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintabundindicates data in table B1meta.ref.urlcharGaiaDR3Gaia DR3 source_idmeta.id;meta.mainTargetIdentifier used throughout the papermeta.idcharprimaryRA_ICRSGaia DR3 right ascension (ICRS) at Ep=2016.0)degpos.eq.ra;meta.mainDE_ICRSGaia DR3 declination (ICRS) at Ep=2016.0)degpos.eq.dec;meta.mainGmagGaia DR3 G magnitudemagphot.mag;em.optfloatSpectrSpectrograph employed: SOPHIE or UVESinstr.ordercharMJDModified Julian Date: start of exposuredtime.epochdoubleMethMethod used: CC (cross-correlation) or TM (template-matching)meta.notecharRV? Radial velocitykm/sphys.veloc;pos.heliocentricdoublenullablee_RV? Radial velocity uncertaintykm/sstat.errorfloatnullableStatusStatus: Conf (confirmed) or Spur (spurious)meta.codecharJ/A+A/704/A294/tableb1Atmospheric parameters, metallicities and alpha-elements over iron abundance ratiosrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTargetIdentifier used throughout the papermeta.idcharTeffEffective temperatureKphys.temperature.effectiveintlogglogarithm of the surface gravitylog(cm.s**-2)phys.gravityfloat[Fe/H]Metallicityphys.abund.Zfloate_[Fe/H]Metallicity uncertaintystat.error;phys.abund.Fefloat[alpha/Fe]? alpha-elements over iron abundance ratiophys.abundfloatnullableSNSpectrum S/N at 500nmstat.snrintGaiaDR3Gaia DR3 source_idmeta.id;meta.main