J/ApJ/790/73ivo://CDS.VizieR/J/ApJ/790/73doi:10.26093/cds/vizier.17900073CDSVargas L.C.Geha M.C.Tollerud E.J.2017-10-13T15:41:07Z2017-03-27T11:51:51ZCDS support team

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

cds-question@unistra.frgalaxiesgiant-starsapparent-magnitudegalaxy-kinematicsmetallicityWe present alpha to iron abundance ratios for 226 individual red giant branch stars in nine dwarf galaxies of the Andromeda (M31) satellite system. The abundances are measured from the combined signal of Mg, Si, Ca, and Ti lines in Keck/DEIMOS medium-resolution spectra. This constitutes the first large sample of alpha abundance ratios measured in the M31 satellite system. The dwarf galaxies in our sample exhibit a variety of alpha abundance ratios, with the average values in each galaxy ranging from approximately solar ([{alpha}/Fe] ~ + 0.0) to alpha-enhanced ([{alpha}/Fe] ~ + 0.5). These variations do not show a correlation with internal kinematics, environment, or stellar density. We confirm radial gradients in the iron abundance of two galaxies out of the five with sufficient data (NGC 185 and And II). There is only tentative evidence for an alpha abundance radial gradient in NGC 185. We homogeneously compare our results to the Milky Way classical dwarf spheroidals, finding evidence for wider variation in average alpha abundance. In the absence of chemical abundances for the M31 stellar halo, we compare to the Milky Way stellar halo. A stellar halo comprised of disrupted M31 satellites is too metal-rich and inconsistent with the Milky Way halo alpha abundance distribution even if considering only satellites with predominantly old stellar populations. The M31 satellite population provides a second system in which to study chemical abundances of dwarf galaxies and reveals a wider variety of abundance patterns than the Milky Way.2014ApJ...790...73Vhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/790/73CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/711/361 : Local Group dE galaxies. II. (Geha+, 2010)J/AJ/144/4 : Properties of dwarf galaxies in the Local GroupJ/ApJ/752/45 : SPLASH: Stellar spectroscopy of M31 satellites (Tollerud+, 2012)J/ApJ/798/77 : Metallicity of RGB stars in 6 M31 dwarf galaxies (Ho+, 2015)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/790/73https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/790/73http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/790/73https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/790/73https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/790/73http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/790/73GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/790/73/table2 (Iron and Alpha Abundance Results)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/790/73/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/790/73/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/790/73/table2?GETtext/xml+votable180.050000true10.663833340.89083330.0055555555555555566/2229 2231 2272 2274 2604 2611 2622 2623 2676 2774 2777 2780 2852 14149https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/790/73?format=asciidefaultJ/ApJ/790/73/table2Iron and Alpha Abundance ResultsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintUFDName of M31 Satellite Galaxymeta.id;meta.maincharRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.main[Fe/H]Iron abundance relative to the Sunlog(Sun)phys.abund.Fefloate_[Fe/H]Uncertainty in [Fe/H]log(Sun)stat.error;phys.abund.Fefloat[a/Fe]? Alpha-to-iron abundance ratiolog(Sun)phys.abundfloatnullableE_[a/Fe]? Upper limit uncertainty in [a/Fe]log(Sun)stat.error;stat.maxfloatnullablee_[a/Fe]? Lower limit uncertainty in [a/Fe]log(Sun)stat.error;phys.abundfloatnullableJ/ApJ/790/73/table1Observed Properties of M31 Satellite SamplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintUFDName of M31 Satellite Galaxymeta.id;meta.maincharVMagV band absolute magnitude (1)magphys.magAbs;em.opt.Vfloate_VMagError in VMagmagstat.error;phot.mag;em.opt.VfloatsigmalosLOS velocity dispersion (2)km/sphys.veloc.dispersionfloate_sigmalosError in sigmaloskm/sstat.errorfloatVrmsQuadrature sum of dispersion and rotation velocity (3)km/sphys.velocfloate_VrmsError in Vrmskm/sstat.errorfloatmuVSurface brightness in V band (4)mag.arcsec**-2phot.mag.sb;em.opt.Vfloate_muVError in muVmag.arcsec**-2stat.errorfloatr1/2Half-light radius (4)arcminphys.angSizefloate_r1/2Error in r1/2arcminstat.errorfloatPAPosition angle (4)degpos.posAngfloatepsilonEllipticity (4)src.ellipticityfloat(m-M)0Distance modulus (5)magphot.mag.distModfloate_(m-M)0Error in (m-M)0magstat.errorfloatN[alpha/Fe]Number of measurements of [alpha/Fe] (6)meta.numberintN[Fe/H]Number of measurements of [Fe/H] (7)meta.numberintSimbadSimbad column added by the CDSmeta.ref.urlchar