J/ApJ/809/143ivo://CDS.VizieR/J/ApJ/809/143doi:10.26093/cds/vizier.18090143CDSDo T.Kerzendorf W.Winsor N.Stostad M.Morris M.R.Lu J.R.,Ghez A.M.2017-09-20T05:14:10Z2016-01-14T14:24:46ZCDS support team

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

cds-question@unistra.frchemical-abundancesradial-velocitygiant-starsmilky-way-galaxyWe present a metallicity analysis of 83 late-type giants within the central 1pc of the Milky Way. K-band spectroscopy of these stars was obtained with the medium spectral resolution integral-field spectrograph NIFS on Gemini North using laser-guided star adaptive optics. Using spectral template fitting with the MARCS synthetic spectral grid, we find that there is a large variation in the metallicity, with stars ranging from [M/H]<-1.0 to above solar metallicity. About 6% of the stars have [M/H]<-0.5. This result is in contrast to previous observations with smaller samples that show stars at the Galactic center having approximately solar metallicity with only small variations. Our current measurement uncertainties are dominated by systematics in the model, especially at [M/H]>0, where there are stellar lines not represented in the model. However, the conclusion that there are low-metallicity stars, as well as large variations in metallicity, is robust. The metallicity may be an indicator of the origin of these stars. The low-metallicity population is consistent with that of globular clusters in the Milky Way, but their small fraction likely means that globular cluster infall is not the dominant mechanism for forming the Milky Way nuclear star cluster. The majority of stars are at or above solar metallicity, which suggests they were formed closer to the Galactic center or from the disk. In addition, our results indicate that it will be important for star formation history analyses using red giants at the Galactic center to consider the effect of varying metallicity.2015ApJ...809..143Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/809/143CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/808/106 : NIR spectroscopic obs. in the Galactic Center (Stostad+, 2015)J/A+A/564/A125 : AGN Torus model comparison of AGN in the CDFS (Buchner+, 2014)J/ApJ/779/L6 : 3D kinematic obs. of stars in Galactic Centre (Do+, 2013)J/ApJ/764/154 : Stellar populations in the central 0.5pc. I. (Do+, 2013)J/A+A/549/A147 : Abundances of microlensed Bulge dwarf stars V. (Bensby+, 2013)J/A+A/549/A129 : Equivalent widths of cool stars (Cesetti+, 2013)J/ApJ/751/132 : Keck observations of the Arches cluster (Clarkson+, 2012)J/A+A/535/A42 : Metal rich stars in solar neighbourhood (Trevisan+, 2011)J/A+A/502/91 : Proper motions of stars near SgrA* (Schoedel+, 2009)J/ApJ/681/1254 : Radial velocities of stars in the Galactic Center (Zhu+, 2008)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/809/143https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/809/143http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/809/143https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/809/143https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/809/143http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/809/143GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/809/143/table1 (Measured physical parameters of stars at the Galactic Center)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/809/143/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/809/143/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/809/143/table1?GETtext/xml+votable180.050000true266.42165556-29.007946670.0055555555555555566/28830https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/809/143?format=asciiOpticaldefaultJ/ApJ/809/143/table1Measured physical parameters of stars at the Galactic CenterrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar namemeta.id;meta.maincharKmag[10.4/16.7] K magnitudephot.mag;em.IR.KfloatS/N[35/133] Signal to noise ratiostat.snrintoRA[1.4/22.73] R.A. offset from SgrA* (1)arcsecpos.eq.ra;arith.difffloatoDE[-4.55/11.57] Dec. offset from SgrA* (1)arcsecpos.eq.dec;arith.difffloatTeff[3447/4613] Effective temperatureKphys.temperature.effectiveinte_Teff[413/425] Teff uncertaintyKstat.error;phys.temperature.effectiveintlogg[2.7/4] Log of Surface gravityphys.gravityfloate_logg[0.91] logg uncertaintystat.errorfloat[M/H][-1.3/1] Metallicityphys.abund.Zfloate_[M/H][0.3/0.4] [M/H] uncertaintystat.error;phys.abundfloatRV[-225/228] Radial velocity {nu}_z_km/sphys.veloc;pos.heliocentricint_RASimbad column added by the CDSdegpos.eq.ra;meta.main_DESimbad column added by the CDSdegpos.eq.dec;meta.main