J/ApJ/808/108ivo://CDS.VizieR/J/ApJ/808/108doi:10.26093/cds/vizier.18080108CDSWalker M.G.Mateo M.Olszewski E.W.Bailey III J.I.Koposov S.E.,Belokurov V.Evans N.W.2017-11-28T13:21:30Z2015-12-21T11:56:56ZCDS support team

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

cds-question@unistra.frmetallicitygalaxiesspectroscopyinfrared-photometryvisible-astronomybroad-band-photometryWe present results from spectroscopic observations with the Michigan/Magellan Fiber System (M2FS) of 182 stellar targets along the line of sight (LOS) to the newly discovered "ultrafaint" object Reticulum 2 (Ret 2). For 37 of these targets, the spectra are sufficient to provide simultaneous estimates of LOS velocity ({nu}i_los_, median random error {delta}_{nu}los_=1.4km/s), effective temperature (T_eff_, {delta}_Tef_=478K), surface gravity (logg, {delta}_logg_=0.63dex), and iron abundance ([Fe/H], {delta}_[Fe/H]_=0.47dex). We use these results to confirm 17 stars as members of Ret 2. From the member sample we estimate a velocity dispersion of {sigma}_{nu}los_=3.6_-0.7_^+1.0^km/s about a mean of <{nu}_los_>=64.3_1.2_^+1.2^km/s in the solar rest frame (~-90.9km/s in the Galactic rest frame), and a metallicity dispersion of {sigma}_[Fe/H]_=0.49_-0.14_^+0.19^dex about a mean of <[Fe/H]_>=-2.58_-0.33_^+0.34^. These estimates marginalize over possible velocity and metallicity gradients, which are consistent with zero. Our results place Ret 2 on chemodynamical scaling relations followed by the Milky Way's dwarf-galactic satellites. Under assumptions of dynamic equilibrium and negligible contamination from binary stars --both of which must be checked with deeper imaging and repeat spectroscopic observations-- the estimated velocity dispersion suggests a dynamical mass of M(R_h_)~5R_h_{sigma}_{nu}los_^2^/(2G)=2.4_-0.8_^+1.4^x10^5^M_{sun}_ enclosed within projected halflight radius R_h_~32pc, with mass-to-light ratio ~2M(R_h_)/L_V_=467_-168_^+286^ in solar units.2015ApJ...808..108Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/808/108CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVII/202 : Globular Clusters in the Milky Way (Harris, 1997)J/ApJ/808/95 : Spectroscopy of Reticulum II (Simon+, 2015)J/MNRAS/448/2717 : Bayesian analysis of resolved spectra (Walker+, 2015)J/ApJ/779/102 : Metallicities of RGB stars in dwarf galaxies (Kirby+, 2013)J/ApJ/776/80 : PAndAS view of Andromeda satellites. I. (Martin+, 2013)J/AJ/144/4 : Properties of Local Group dwarf gal. (McConnachie+, 2012)J/ApJ/736/146 : Radial velocities of stars in Bootes I (Koposov+, 2011)J/AJ/136/2050 : SEGUE stellar parameter pipeline. II. (Lee+, 2008)J/MNRAS/380/281 : Faint galactic satellites spectrosc. survey (Martin+, 2007)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/808/108https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/808/108http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/808/108https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/808/108https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/808/108http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/808/108GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/808/108/table1 (M2FS stellar spectroscopy of Reticulum 2)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/808/108/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/808/108/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/808/108/table1?GETtext/xml+votable180.050000true53.9844583-54.05450.0055555555555555566/33626 33627https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/808/108?format=asciiInfraredOpticaldefaultJ/ApJ/808/108/table1M2FS stellar spectroscopy of Reticulum 2recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRet2[4/178] Target Identifiermeta.id;meta.mainintRAJ2000[3] Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000[53/54] Degree of Declination (J2000)pos.eq.dec;meta.mainR[1.2/18] Angular Separation from Centerarcminpos.angDistancefloatgmag[17.3/20.7] Magnitude in g band (1)magphot.mag;em.opt.Bfloatrmag[16.8/20.3] Magnitude in r band (1)magphot.mag;em.opt.RfloatS/N[1/16] Median Signal/Noise Ratio per pixelem.wl.central;stat.medianfloatVlos[16/309] Solar rest frame line-of-sight velocity ({nu}_los_)km/sphys.velocfloate_Vlos[0.4/3.3] Uncertainty in Vloskm/sstat.errorfloatsVlos[-0.5/0.9] Skewness in Vlosstat.fit.paramfloatkVlos[2/4] Kurtosis in Vlosstat.fit.paramfloatTeff[4494/6506] Effective TemperatureKphys.temperature.effectiveinte_Teff[50/1034] Uncertainty in TeffKstat.error;phys.temperature.effectiveintsTeff[-0.4/2.1] Skewness in Teffstat.fit.paramfloatkTeff[2/9.2] Kurtosis in Teffstat.fit.paramfloatlogg[0.5/4.8] Log surface gravitylog(cm.s**-2)phys.gravityfloate_logg[0.1/1.3] Uncertainty in logglog(cm.s**-2)stat.errorfloatslogg[-1.7/0.8] Skewness in loggstat.fit.paramfloatklogg[2.2/6.8] Kurtosis in loggstat.fit.paramfloat[Fe/H][-3.6/-0.01] Metallicityphys.abund.Zfloate_[Fe/H][0.04/1.1] Uncertainty in [Fe/H]stat.error;phys.abund.Fefloats[Fe/H][-0.6/1.5] Skewness in [Fe/H]stat.fit.paramfloatk[Fe/H][2/5.7] Kurtosis in [Fe/H]stat.fit.paramfloatMm?Member of Ret 2? (Y/N)meta.code.membercharSimbadSimbad column added by the CDSmeta.ref.urlchar