J/AJ/153/254ivo://CDS.VizieR/J/AJ/153/254doi:10.26093/cds/vizier.51530254CDSSpencer M.E.Mateo M.Walker M.G.Olszewski E.W.McConnachie A.W.,Kirby E.N.Koch A.2019-08-20T06:57:59Z2018-05-30T12:49:26ZCDS support team

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

cds-question@unistra.frgalaxiesgiant-starsradial-velocityWe combine precision radial velocity data from four different published works of the stars in the Leo II dwarf spheroidal galaxy. This yields a data set that spans 19 years, has 14 different epochs of observation, and contains 372 unique red giant branch stars, 196 of which have repeat observations. Using this multi-epoch data set, we constrain the binary fraction for Leo II. We generate a suite of Monte Carlo simulations that test different binary fractions using Bayesian analysis and determine that the binary fraction for Leo II ranges from 0.30_-0.10_^+0.09^ to 0.34_-0.11_^+0.11^, depending on the distributions of binary orbital parameters assumed. This value is smaller than what has been found for the solar neighborhood (~0.4-0.6) but falls within the wide range of values that have been inferred for other dwarf spheroidals (0.14-0.69). The distribution of orbital periods has the greatest impact on the binary fraction results. If the fraction we find in Leo II is present in low-mass ultra-faints, it can artificially inflate the velocity dispersion of those systems and cause them to appear more dark matter rich than in actuality. For a galaxy with an intrinsic dispersion of 1 km/s and an observational sample of 100 stars, the dispersion can be increased by a factor of 1.5-2 for Leo II-like binary fractions or by a factor of three for binary fractions on the higher end of what has been seen in other dwarf spheroidals.2017AJ....153..254Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/153/254CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/120/284 : Variables in Leo II dwarf spheroidal (Siegel+, 2000)J/MNRAS/360/185 : VI photometry of the Leo II galaxy (Bellazzini+, 2005)J/AJ/133/270 : Metallicities and ages in Leo II dSph (Koch+, 2007)J/AJ/134/566 : Leo II stellar kinematics (Koch+, 2007)J/MNRAS/378/318 : Chemical abundances in Leo I and II dSph (Bosler+, 2007)J/MNRAS/388/1185 : JHKs photometry of LeoII dSph giants (Gullieuszik+, 2008)J/ApJS/191/352 : Abundances in stars of Milky Way dwarf satellitesJ/ApJ/741/100 : Proper motions of Leo II member stars (Lepine+, 2011)J/ApJ/836/202 : Kinematic study of the Leo II dwarf galaxy (Spencer+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/153/254https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/153/254http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/153/254https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/153/254https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/153/254http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/153/254GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/153/254/table2 (Velocities of RGB stars in Leo II)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/153/254/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/153/254/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/153/254/table2?GETtext/xml+votable180.050000true168.392958322.153250.0055555555555555566/28361https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/153/254?format=asciidefaultJ/AJ/153/254/table2Velocities of RGB stars in Leo IISimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintLeoII-[1/196] Stellar identifier (LeoII-NNN)meta.id;meta.mainintNum[2/7] Number of observationsmeta.numberintRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainHJDHeliocentric Julian Datedtime.epochdoubleRV[52.4/103.01] Radial velocity (1)km/sphys.veloc;pos.heliocentricfloate_RV[0.54/31.61] Uncertainty in RVkm/sstat.errorfloatr_RVReference for RV (2)meta.ref;pos.framechar