J/MNRAS/501/5981ivo://CDS.VizieR/J/MNRAS/501/5981doi:10.26093/cds/vizier.75015981CDSLucey M.Hawkins K.Ness M.Debattista V.P.Luna A.Asplund M.,Bensby T.Casagrande L.Feltzing S.Freeman K.C.Kobayashi C.,Marino A.F.2024-08-21T20:17:10Z2021-10-18T09:02:07ZCDS support team

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

cds-question@unistra.frsurveyspopulation-ii-starsradial-velocitymilky-way-galaxyvisible-astronomyThe metal-poor stars in the bulge are important relics of the Milky Way's formation history, as simulations predict that they are some of the oldest stars in the Galaxy. In order to determine if they are truly ancient stars, we must understand their origins. Currently, it is unclear if the metal-poor stars in the bulge ([Fe/H]<-1dex) are merely halo interlopers, a unique accreted population, part of the boxy/peanut-shaped bulge, or a classical bulge population. In this work, we use spectra from the VLT/FLAMES spectrograph to obtain metallicity estimates using the Ca-II triplet of 473 bulge stars (187 of which have [Fe/H]<-1dex), targeted using SkyMapper photometry. We also use Gaia DR2 data to infer the Galactic positions and velocities along with orbital properties for 523 stars. We employ a probabilistic orbit analysis and find that about half of our sample has a >50 per cent probability of being bound to the bulge, and half are halo interlopers. We also see that the occurrence rate of halo interlopers increases steadily with decreasing metallicity across the full range of our sample (-3<[Fe/H]<0.5). Our examination of the kinematics of the confined compared to the unbound stars indicates the metal-poor bulge comprises at least two populations; those confined to the boxy/peanut bulge and halo stars passing through the inner galaxy. We conclude that an orbital analysis approach, as we have employed, is important to understand the composite nature of the metal-poor stars in the inner region.2021MNRAS.501.5981Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/501/5981CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/345 : Gaia DR2 (Gaia Collaboration, 2018)J/MNRAS/488/2283 : COMBS survey. Galactic Bulge metal-poor stars (Lucey+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/501/5981https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/501/5981http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/501/5981https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/501/5981https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/501/5981http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/501/5981GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/501/5981/tablea1 (Dynamical properties of our target stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/501/5981/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/501/5981/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/501/5981/tablea1?GETtext/xml+votable180.050000true276.069-33.545230.0055555555555555566/28737 28739-28740 28742 28792 28794 29026-29027 29033 47803 47806https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/501/5981?format=asciiOpticaldefaultJ/MNRAS/501/5981/tablea1Dynamical properties of our target starsVvelV velocity (V)km/sphys.veloc;pos.cartesian.ydoubleSNRSignal-to-noise ratio (SNR)stat.snrintb_YposLower value of Y interval (Y_lo)pcpos.cartesian.y;stat.minfloatB_YposUpper value of Y interval (Y_hi)pcpos.cartesian.y;stat.maxfloatZposZ position (Z)pcpos.distance;pos.cartesian.zfloatb_ZposLower value of Z interval (Z_lo)pcsrc.redshift;stat.minfloatB_ZposUpper value of Z interval (Z_hi)pcsrc.redshift;stat.maxfloatdDistance (d)kpcpos.distancedoubleb_dLower value of Distance interval (d_lo)kpcpos.distance;time.interval;stat.mindoubleB_dUpper value of Distance interval (d_hi)kpcpos.distance;time.interval;stat.maxdoubleProbPobability that a star stays confined to the bulge (prob)meta.notefloatperiPericentre (peri)kpcpos.distance;src.orbitaldoubleb_periLower value of peri interval (peri_lo)kpctime.interval;stat.mindoubleB_periUpper value of peri interval (peri_hi)kpctime.interval;stat.maxdoubleapiApocentre (api)kpcpos.distance;src.orbitaldoubleb_apiLower value of api interval (api_lo)kpctime.interval;stat.mindoubleB_apiUpper value of api interval (api_hi)kpctime.interval;stat.maxdoubleeExcentricity (e)src.orbital.eccentricitydoubleb_eLower value of e interval (e_lo)time.interval;stat.mindoubleB_eUpper value of e interval (e_hi)time.interval;stat.maxdoublezmaxMaximun height above the plane (zmax)pcpos.cartesian.z;pos.galacticdoubleb_zmaxLower value of e zmax (zmax_lo)pcpos.cartesian.z;pos.galactic;stat.mindoubleB_zmaxUpper value of e zmax (zmax_hi)pcpos.cartesian.z;pos.galactic;stat.maxdoubleobjectObject designation (object)meta.id;meta.maincharSourceGaia source ID (some erroneous identifiers) (source_id)meta.idRA_ICRSRight ascension (ICRS) (ra)degpos.eq.ra;meta.mainDE_ICRSDeclination (ICRS) (dec)degpos.eq.dec;meta.mainGLON[0/360] Galactic longitude (l)degpos.galactic.lonGLATGalactic latitude (b)degpos.galactic.latdouble[Fe/H]? Metallicity ([Fe/H])phys.abund.Zfloatnullablee_[Fe/H]? Metallicity error (e_[Fe/H])stat.error;phys.abund.FefloatnullableRVRadial velocity (RV)km/sphys.veloc;pos.heliocentricdoublee_RVRadial velocity error (e_RV)km/sstat.errorfloatRUWERenormalised unit weight error (ruwe)stat.errordoubleSpec[GU] Spectra origin (Spec) (1)meta.codecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSimbadNameSimbad column added by the CDSmeta.idcharnullableUvelU velocity (U)km/sphys.veloc;pos.cartesian.xdoubleb_UvelLower value of U interval (U_lo)km/stime.interval;pos.cartesian.xdoubleB_UvelUpper value of U interval (U_hi)km/stime.interval;pos.cartesian.xdoubleb_VvelLower value of V interval (V_lo)km/stime.interval;pos.cartesian.ydoubleB_VvelUpper value of V interval (V_hi)km/stime.interval;pos.cartesian.ydoubleWvelW velocity (W)km/sphys.veloc;pos.cartesian.zdoubleb_WvelLower value of W interval (W_lo)km/sphys.veloc;pos.cartesian.z;stat.mindoubleB_WvelUpper value of W interval (W_hi)km/sphys.veloc;pos.cartesian.z;stat.maxdoubleXposX position (X)pcpos.distance;pos.cartesian.xdoubleb_XposLower value of X interval (X_lo)pcpos.cartesian.x;stat.mindoubleB_XposUpper value of X interval (X_hi)pcpos.cartesian.x;stat.maxdoubleYposY position (Y)pcpos.distance;pos.cartesian.yfloat