J/AJ/159/254ivo://CDS.VizieR/J/AJ/159/254doi:10.26093/cds/vizier.51590254CDSJohnson C.I.Dupree A.K.Mateo M.Bailey J.I.Olszewski E.W.,Walker M.G.2022-09-30T06:31:49Z2020-10-14T07:16:42ZCDS support team

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

cds-question@unistra.frglobular-star-clusterschemically-peculiar-starsvisible-astronomyspectroscopyinfrared-astronomymetallicityradial-velocityThe most massive and complex globular clusters in the Galaxy are thought to have originated as the nuclear cores of now tidally disrupted dwarf galaxies, but the connection between globular clusters and dwarf galaxies is tenuous with the M54/Sagittarius system representing the only unambiguous link. The globular cluster Omega Centauri ({omega}Cen) is more massive and chemically diverse than M54, and is thought to have been the nuclear star cluster of either the Sequoia or Gaia-Enceladus galaxy. Local Group dwarf galaxies with masses equivalent to these systems often host significant populations of very metal-poor stars ([Fe/H]<-2.5), and one might expect to find such objects in {omega}Cen. Using high-resolution spectra from Magellan-M2FS, we detected 11 stars in a targeted sample of 395 that have [Fe/H] ranging from -2.30 to -2.52. These are the most metal-poor stars discovered in the cluster, and are five times more metal-poor than {omega}Cen's dominant population. However, these stars are not so metal-poor as to be unambiguously linked to a dwarf galaxy origin. The cluster's metal-poor tail appears to contain two populations near [Fe/H]~-2.1 and -2.4, which are very centrally concentrated but do not exhibit any peculiar kinematic signatures. Several possible origins for these stars are discussed.2020AJ....159..254Jhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/159/254CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/358 : SkyMapper Southern Sky Survey. DR1.1 (Wolf+, 2018)VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)J/ApJ/462/241 : Ca abundance for Omega Cen red giants (Norris+ 1996)J/A+A/360/472 : Proper motions in omega Centauri (van Leeuwen+, 2000)J/AJ/127/958 : CCD BV photometry on Omega Cen (Rey+, 2004)J/MNRAS/357/265 : BVI photometry of omega Cen red giants (Sollima+, 2005)J/A+A/459/423 : VI and [Fe/H] of Fornax dSph RGB stars (Battaglia+, 2006)J/A+A/445/503 : Radial velocities in Omega Cen (NGC5139) (Reijns+, 2006)J/A+A/465/357 : Stroemgren photometry in the Draco dSph galaxy (Faria+,2007)J/MNRAS/382/1353 : Spectral atlas of omega Cen post-MS stars (van Loon+, 2007)J/ApJ/663/296 : UBV phot. omega Cen (NGC5139) subgiants (Villanova+, 2007)J/AJ/136/1039 : CaII index of SMC red giant branch stars (Carrera+, 2008)J/ApJ/681/1505 : Abundances of red giants in {omega} Cen (Johnson+, 2008)J/ApJ/706/1277 : Stromgren photometry in {omega} Cen (Calamida+, 2009)J/MNRAS/396/1075 : Globular cluster nearby dwarf galaxies. II (Georgiev+, 2009)J/ApJ/705/328 : Abundance measurements in Sculptor dSph (Kirby+, 2009)J/MNRAS/396/2183 : Radial velocities red giants in {omega}Cen (Sollima+, 2009)J/AJ/140/631 : HST WFC3/UVIS photometry of omega Cen core (Bellini+, 2010)J/A+A/520/A95 : Abundances of red giants in M54 & Sgr dSph (Carretta+, 2010)J/ApJ/722/1373 : {omega} Centauri giants abundances (Johnson+, 2010)J/ApJ/731/64 : Spectroscopy of 300 RGBs in {omega} Cen (Marino+, 2011)J/MNRAS/416/L6 : AGB and RGB stars in {omega} Cen (McDonald+, 2011)J/A+A/534/A53 : Equivalent widths of 18 subgiant {omega}Cen (Pancino+, 2011)J/A+A/527/A18 : EW of 6 subgiants of {omega} Cen (Pancino+, 2011)J/ApJ/779/102 : Metallicities of RGB stars in dwarf galaxies (Kirby+, 2013)J/A+A/572/A82 : Abundances in outer parts of Fornax dSph (Hendricks+, 2014)J/ApJ/795/22 : Iron abundance of Terzan 5 stars (Massari+, 2014)J/ApJ/791/107 : Parameters of NGC 5139 SGBs stars (Villanova+, 2014)J/MNRAS/450/815 : Red giants in NGC 5286 (Marino+, 2015)J/ApJ/819/103 : Abundances of two very metal-poor stars (Afsar+, 2016)J/AJ/154/150 : Spectroscopy of RGB stars in {omega} Centauri (An+, 2017)J/ApJ/844/164 : HST astro-photo. analysis of NGC5139. III. (Bellini+, 2017)J/ApJ/836/168 : Abundances & RVs for stars near NGC6273 (Johnson+, 2017)J/MNRAS/466/2006 : Phoenix dwarf galaxy RV and [Fe/H] catalog (Kacharov+, 2017)J/A+A/618/A134 : Omega Cen lower red giant stars abund. (Mucciarelli+, 2018)J/ApJS/245/5 : Globular cluster intrinsic iron abund. spreads (Bailin,2019)J/ApJ/870/115 : Reddening, dist. modulus & Fe/H of RRLs in wCen (Bono+,2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/159/254https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/159/254http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/159/254https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/159/254https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/159/254http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/159/254GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/159/254/table1 (Sky coordinates, photometry, model atmosphere parameters, iron abundances, errors, and radial Velocities)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/159/254/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/159/254/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/159/254/table1?GETtext/xml+votable180.050000true201.44247-47.188510.0055555555555555566/43225 432277.952274030004205e-20 1.0188844282367877e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/159/254?format=asciiOpticalInfrareddefaultJ/AJ/159/254/table1Sky coordinates, photometry, model atmosphere parameters, iron abundances, errors, and radial VelocitiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintLeid[4013/98012] Leid identification (Cl* NGC 5139 Leid NNNNN)meta.id;meta.mainintRAJ2000[201.07/202.04] Degree of right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-47.9/-47.18] Degree of declination (J2000)degpos.eq.dec;meta.mainVmag[11.9/14.7] Visual magnitudemagphot.mag;em.opt.VfloatJmag[10.1/13.2]? J band magnitudemagphot.mag;em.IR.JfloatnullableKsmag[9.35/12.8]? Ks band magnitudemagphot.mag;em.IR.KfloatnullableTeff[4282/5822]? Effective temperatureKphys.temperature.effectiveintnullablelogg[1.1/2.56]? Surface gravitycm.s**-2phys.gravityfloatnullable[Fe/H][-2.52/-0.81]? Metallicityphys.abund.Zfloatnullablee_[Fe/H][0.11/0.16]? Error on [Fe/H] ({Delta}[Fe/H])stat.error;phys.abund.Fefloatnullableksi[0.9/1.89]? Microturbulence velocity ({ksi}_mic_)km/sphys.veloc.microTurbfloatnullableS/N[0.01/0.09]? Signal to noise ratio ({sigma}/sqrtN)stat.snrfloatnullableNobs[4/14]? Number of observationsmeta.numberintnullableRVel[186/272] Heliocentric radial velocitykm/sspect.dopplerVeloc;pos.heliocentricfloate_RVel[0.1/6.1] Error on RVelkm/sstat.error;spect.dopplerVelocfloatSimbadSimbad column added by the CDSmeta.ref.urlchar