J/ApJ/889/177ivo://CDS.VizieR/J/ApJ/889/177doi:10.26093/cds/vizier.18890177CDSEscala I.Gilbert K.M.Kirby E.N.Wojno J.Cunningham E.C.,Guhathakurta P.2022-11-03T07:06:39Z2021-08-12T09:40:24ZCDS support team

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

cds-question@unistra.frgalaxieschemical-abundancesgiant-starsradial-velocityhalo-starsWe measured [Fe/H] and [{alpha}/Fe] using spectral synthesis of low-resolution stellar spectroscopy for 70 individual red-giant-branch stars across four fields spanning the outer disk, Giant Stellar Stream (GSS), and inner halo of M31. Fields at M31-centric projected distances of 23kpc in the halo, 12kpc in the halo, 22kpc in the GSS, and 26kpc in the outer disk are {alpha}-enhanced, with <[{alpha}/Fe]>=0.43, 0.50, 0.41, and 0.58, respectively. The 23 and 12kpc halo fields are relatively metal-poor, with <[Fe/H]>=-1.54 and -1.30, whereas the 22kpc GSS and 26kpc outer disk fields are relatively metal-rich with <[Fe/H]>=-0.84 and -0.92, respectively. For fields with substructure, we separated the stellar populations into kinematically hot stellar halo components and kinematically cold components. We did not find any evidence of a radial [{alpha}/Fe] gradient along the high surface brightness core of the GSS between ~17 and 22kpc. However, we found tentative suggestions of a negative radial [{alpha}/Fe] gradient in the stellar halo, which may indicate that different progenitor(s) or formation mechanisms contributed to the build up of the inner versus outer halo. Additionally, the [{alpha}/Fe] distribution of the metal-rich ([Fe/H]>-1.5), smooth inner stellar halo (r_proj_<~26kpc) is inconsistent with having formed from the disruption of a progenitor(s) similar to present-day M31 satellite galaxies. The 26kpc outer disk is most likely associated with the extended disk of M31, where its high {alpha}-enhancement provides support for an episode of rapid star formation in M31's disk possibly induced by a major merger.2020ApJ...889..177Ehttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/889/177CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/345 : Gaia DR2 (Gaia Collaboration, 2018)J/AJ/128/1177 : Galactic stellar abundances (Venn+, 2004)J/A+A/433/185 : Abundance analysis of 102 F and G dwarfs (Bensby+, 2005)J/MNRAS/367/1329 : Elemental abundances for 176 stars (Reddy+, 2006)J/MNRAS/383/183 : CaII triplet of RGB from VLT/FLAMES obs. (Battaglia+, 2008)J/ApJ/682/1217 : Abundances in red giants in 7 globular clusters (Kirby+, 2008)J/ApJS/184/152 : Deep optical photometry in M31 (Brown+, 2009)J/ApJ/705/328 : Abundance measurements in Sculptor dSph (Kirby+, 2009)J/AJ/137/272 : Space velocities orbits in the Milky Way halo (Roederer+ 2009)J/ApJ/714/663 : Stellar density map of the Milky Way (de Jong+, 2010)J/ApJS/191/352 : Abundances in stars of MW dwarf satellites (Kirby+, 2010)J/A+A/511/L10 : Abundances and space velocities of 94 stars (Nissen+, 2010)J/ApJ/735/L46 : Spectroscopy of 64 K red giants (Bensby+, 2011)J/ApJ/743/19 : Photometry of variable star cand. in M31 (Clementini+, 2011)J/ApJ/753/64 : Detailed abundances for 97 metal-poor stars (Ishigaki+, 2012)J/AJ/144/4 : Dwarf galaxies in the Local Group (McConnachie+, 2012)J/ApJ/771/67 : Abundances for 97 metal-poor stars. II. (Ishigaki+, 2013)J/ApJ/779/102 : Metallicities of RGB stars in dwarf galaxies (Kirby+, 2013)J/A+A/572/A33 : Abundances from Gaia-ESO Survey (Mikolaitis+, 2014)J/ApJ/790/73 : Iron & alpha abund. of RGBs in M31 satellites (Vargas+, 2014)J/ApJ/789/147 : Star formation histories of LG dwarf galaxies (Weisz+, 2014)J/A+A/577/A81 : Deep SDSS Optical Spectroscopy. II. (Fernandez-Alvar+, 2015)J/ApJ/798/77 : Metallicity of RGB stars in 6 M31 dwarf galaxies (Ho+, 2015)J/MNRAS/455/199 : CaII triplet in red giant spectra (Da Costa, 2016)J/ApJ/819/135 : Lithium-rich giants in globular clusters (Kirby+, 2016)J/ApJ/846/145 : PHAT. XIX. Formation history of M31 disk (Williams+, 2017)J/ApJ/859/L8 : Properties of TriAnd stars (Hayes+, 2018)J/ApJ/852/49 : Properties of metal-poor stars in APOGEE DR13 (Hayes+, 2018)J/ApJ/868/55 : Structure of M31 halo. II. PAndAS (McConnachie+, 2018)J/ApJ/883/128 : alpha & Fe abund. in the giant stellar stream (Gilbert+, 2019)J/AJ/159/46 : Abundances of 416 stars in 5 dSphs of M31 (Kirby+, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/889/177https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/889/177http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/889/177https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/889/177https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/889/177http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/889/177GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/889/177/table6 (Stellar parameters and elemental abundances of individual M31 RGB stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/889/177/table6?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/889/177/table6?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/889/177/table6?GETtext/xml+votable180.050000true11.555791740.66952780.0055555555555555566/2620-2621 2623 2667https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/889/177?format=asciidefaultJ/ApJ/889/177/table6Stellar parameters and elemental abundances of individual M31 RGB starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFieldField (1)meta.id;obs.fieldcharID[2493/3000724] Object Namemeta.id;meta.mainintRAJ2000[0] Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000[39/42] Degree of Declination (J2000)pos.eq.dec;meta.mainHRV[-552/-102] Heliocentric Radial Velocitykm/sspect.dopplerVeloc;pos.heliocentricfloatSN[4/32] Signal-to-noise ratio per Angstromnm**-1stat.snrfloatTeff[3569/5257] Stellar surface temperatureKphys.temperatureinte_Teff[2/2399] Uncertainty in Teff (2)Kstat.error;phys.temperature.effectiveintlogg[0.39/1.85] log of stellar surface gravitylog(cm.s**-2)phys.gravityfloat[Fe/H][-3.52/-0.02] Metallicityphys.abund.Zfloate_[Fe/H][0.13/0.32] Uncertainty in [Fe/H] (2)stat.error;phys.abund.Fefloat[a/Fe][-0.6/1.2]? {alpha} metal abundancephys.abund.Zfloatnullablee_[a/Fe][0.17/0.5]? Uncertainty [a/Fe] (2)stat.error;phys.abundfloatnullableSimbadSimbad column added by the CDSmeta.ref.urlchar