J/ApJ/857/145ivo://CDS.VizieR/J/ApJ/857/145doi:10.26093/cds/vizier.18570145CDSLi T.S.Simon J.D.Pace A.B.Torrealba G.Kuehn K.Drlica-Wagner A.,Bechtol K.Vivas A.K.van der Marel R.P.Wood M.Yanny B.Belokurov V.,Jethwa P.Zucker D.B.Lewis G.Kron R.Nidever D.L.Sanchez-Conde M.A.,Ji A.P.Conn B.C.James D.J.Martin N.F.Martinez-Delgado D.,Noel N.E.D.2021-07-08T14:28:49Z2019-04-25T13:47:13ZCDS support team

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

cds-question@unistra.frgalaxiesspectroscopyradial-velocitymetallicityline-intensitiesinfrared-photometryvisible-astronomybroad-band-photometryWe present Magellan/IMACS, Anglo-Australian Telescope/AAOmega+2dF, and Very Large Telescope/GIRAFFE+FLAMES spectroscopy of the Carina II (CarII) and Carina III (CarIII) dwarf galaxy candidates, recently discovered in the Magellanic Satellites Survey (MagLiteS). We identify 18 member stars in Car II, including two binaries with variable radial velocities and two RR Lyrae stars. The other 14 members have a mean heliocentric velocity v_hel_=477.2+/-1.2km/s and a velocity dispersion of {sigma}_v_=3.4_-0.8_^+1.2^km/s. Assuming Car II is in dynamical equilibrium, we derive a total mass within the half-light radius of 1.0_-0.4_^+0.8^x10^6^M_{sun}_, indicating a mass-to-light ratio of 369_-161_^+309^M_{sun}_/L_{sun}_. From equivalent width measurements of the calcium triplet lines of nine red giant branch (RGB) stars, we derive a mean metallicity of [Fe/H]=-2.44+/-0.09 with dispersion {sigma}_[Fe/H]_=0.22_-0.07_^+0.10^. Considering both the kinematic and chemical properties, we conclude that CarII is a dark-matter-dominated dwarf galaxy. For CarIII, we identify four member stars, from which we calculate a systemic velocity of v_hel_=284.6_-3.1_^+3.4^km/s. The brightest RGB member of CarIII has a metallicity of [Fe/H]=-1.97+/-0.12. Due to the small size of the Car III spectroscopic sample, we cannot conclusively determine its nature. Although these two systems have the smallest known physical separation ({Delta}d~10kpc) among Local Group satellites, the large difference in their systemic velocities, ~200km/s, indicates that they are unlikely to be a bound pair. One or both systems are likely associated with the Large Magellanic Cloud (LMC), and may remain LMC satellites today. No statistically significant excess of {gamma}-ray emission is found at the locations of Car II and Car III in eight years of Fermi-LAT data.2018ApJ...857..145Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/857/145CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/108/1016 : Kinematics of local RR lyrae stars. I. (Layden, 1994)J/ApJ/649/201 : Velocities & Washington photom. in Carina dSph (Munoz+, 2006)J/AJ/131/2114 : Radial velocities in Fornax dSph (Walker+, 2006)J/ApJ/663/960 : Radial velocities of Leo I stars (Sohn+, 2007)J/AJ/136/1645 : Spectroscopy of bright QUEST RR Lyrae stars (Vivas+, 2008)J/ApJ/694/L144 : Spectroscopic study of Leo V dSph (Walker+, 2009)J/ApJ/710/1664 : BV photometry in Leo IV and Leo V dSphs (de Jong+, 2010)J/MNRAS/434/1681 : Extremely metal-poor stars CaII triplet (Carrera+, 2013)J/ApJ/779/102 : Metallicities of RGB stars in dwarf galaxies (Kirby+, 2013)J/ApJS/218/23 : Fermi LAT third source catalog (3FGL) (Acero+, 2015)J/ApJ/799/86 : Isotropic diffuse gamma-ray emission (Ackermann+, 2015)J/ApJ/801/74 : Dark matter profiles in dwarf gal. (Geringer-Sameth+, 2015)J/ApJ/808/95 : Spectroscopy of Reticulum II (Simon+, 2015)J/ApJ/829/108 : Kinematic data of Galactic globular clusters (Eadie+, 2016)J/ApJ/817/41 : Abundances of 4 metal-poor red giants in BooII (Ji+, 2016)J/ApJ/819/53 : Magellan/M2FS spectrosc. of Tucana 2 & Grus 1 (Walker+, 2016)J/ApJ/838/83 : RVs, abundances & membership in TriII (Kirby+, 2017)J/AJ/154/199 : Survey of the MAgellanic Stellar History (Nidever+, 2017)J/ApJ/838/11 : Member stars in the MW satellite Tucana III (Simon+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/857/145https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/857/145http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/857/145https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/857/145https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/857/145http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/857/145GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/857/145/table2 (*Summary of properties of Carina II and Carina III)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/857/145/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/857/145/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/857/145/table2?GETtext/xml+votable180.050000true114.1066-57.99910.005555555555555556Cone search capability for table J/ApJ/857/145/table4 (Velocity and metallicity measurements)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/857/145/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/857/145/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/857/145/table4?GETtext/xml+votable180.050000true113.77049-57.946360.0055555555555555566/37615 38981https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/857/145?format=asciiOpticalInfrareddefaultJ/ApJ/857/145/table2*Summary of properties of Carina II and Carina IIISimbadNameSimbad column added by the CDSmeta.idcharf_logJ0.1Flag on logJ0.1 (2)meta.codecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameDwarf galaxy namemeta.id;meta.maincharRAJ2000[114.1/114.7] Right ascension (J2000) (1)degpos.eq.ra;meta.maine_RAJ2000[0.006/0.007] RAdeg uncertainty (1)degstat.error;pos.eq.rafloatDEJ2000[-58/-57.8] Declination (J2000) (1)degpos.eq.dec;meta.maine_DEJ2000[0.008/0.01] DEdeg uncertainty (1)degstat.error;pos.eq.decfloatm-M[17.2/17.9] Distance modulus (1)magphot.mag.distModfloate_m-M[0.02/0.1] m-M uncertainty (1)magstat.errorfloatf_m-MFlag on m-M (2)meta.codecharDist[27.8/37.4] Heliocentric distance (1)kpcpos.distancefloate_Dist[0.4/0.6] Dist uncertainty (1)kpcstat.errorfloatf_DistFlag on Dist (2)meta.codecharVMag[-4.5/-2.4] V-band absolute magnitude (1)magphot.magfloate_VMag[0.1/0.2] Vmag uncertainty (1)magstat.error;phot.magfloatLV[780/5400] V-band luminosity (1)solLumphys.luminosity;em.optdoublee_LV[130/500] Negative uncertainty in LV (1)solLumstat.errordoubleE_LV[160/500] Positive uncertainty in LV (1)solLumstat.error;stat.maxdoubler1/2[3.7/8.7] Half-light radius (1)arcminphys.angSizefloate_r1/2[0.7/1] r1/2 uncertainty (1)arcminstat.errorfloatr1/2pc[30/91] Half-light radius in parsecs (1)pcphys.size.radiusinte_r1/2pc[8/9] r1/2pc uncertainty (1)pcstat.errorintell[0.34/0.55] Ellipticity, 1-b/a (1)src.ellipticityfloate_ell[0.07/0.18] ell uncertainty (1)stat.errorfloatPA[150/170] Position angle, N to E (1)degpos.posAnginte_PA[9/14] PA uncertainty (1)degstat.errorintNm[4/14] Number of membersmeta.numberintf_NmFlag on Nm (2)meta.codecharHRV[284.6/477.2] Heliocentric velocitykm/sspect.dopplerVeloc;pos.heliocentricfloate_HRV[1.2/3.1] Negative uncertainty in HRVkm/sstat.errorfloatE_HRV[1.2/3.4] Positive uncertainty in HRVkm/sstat.error;stat.maxfloatVGSR[42/235] Galactic standard of rest velocitykm/sphys.veloc;pos.galacticintsigma[3.4/5.6] Dispersion velocitykm/sphys.veloc.dispersionfloate_sigma[0.8/2.1] Negative uncertainty on sigmakm/sstat.errorfloatE_sigma[1.2/4.3] Positive uncertainty on sigmakm/sstat.error;stat.maxfloatf_sigmaFlag on sigma (2)meta.codecharMhalf[1e+06]? Dynamical masssolMassphys.massdoublenullablee_Mhalf[400000]? Negative uncertainty on MhalfsolMassstat.errordoublenullableE_Mhalf[800000]? Positive uncertainty on MhalfsolMassstat.error;stat.maxdoublenullableM/LV[369]? Mass-to-light ratiosolMass/solLumphys.composition.massLightRatiointnullablee_M/LV[161]? Negative uncertainty on M/LVsolMass/solLumstat.errorintnullableE_M/LV[309]? Positive uncertainty on M/LVsolMass/solLumstat.error;stat.maxintnullabledv/dx[0]? d{nu}/d{xi} valuekm.s**-1.arcmin**-1stat.fit.paramfloatnullablee_dv/dx[0.3]? dv/dx uncertaintykm.s**-1.arcmin**-1stat.errorfloatnullableMetal[-2.5/-1.9] Mean metallicityphys.abund.Zfloatf_MetalFlag on Metal (2)meta.codechare_Metal[0.09]? Metal uncertaintystat.error;phys.abund.ZfloatnullabledMet[0.22]? Metallicity dispersion (dex)stat.variance;phys.abund.Zfloatnullablee_dMet[0.07]? Negative uncertainty on dMetstat.errorfloatnullableE_dMet[0.1]? Positive uncertainty on dMetstat.error;stat.maxfloatnullablelogJ0.1[17.9/19.9] 0.1{deg} J-factor (3)GeV**2.cm**-5stat.fit.paramfloate_logJ0.1[0.5/0.9] Negative uncertainty in logJ0.1GeV**2.cm**-5stat.errorfloatE_logJ0.1[0.6/1] Positive uncertainty in logJ0.1GeV**2.cm**-5stat.error;stat.maxfloatlogJ0.5[18.2/20.2] 0.5{deg} J-factor (3)GeV**2.cm**-5stat.fit.paramfloate_logJ0.5[0.5/0.9] Negative uncertainty in logJ0.5GeV**2.cm**-5stat.errorfloatE_logJ0.5[0.5/1] Positive uncertainty in logJ0.5GeV**2.cm**-5stat.error;stat.maxfloatf_logJ0.5Flag on logJ0.5 (2)meta.codecharlogD0.1[16.9/17.8] 0.1{deg} D-factor (3)GeV**2.cm**-5stat.fit.paramfloate_logD0.1[0.3/0.5] Negative uncertainty in logD0.1GeV**2.cm**-5stat.errorfloatE_logD0.1[0.3/0.5] Positive uncertainty in logD0.1GeV**2.cm**-5stat.error;stat.maxfloatf_logD0.1Flag on logD0.1 (2)meta.codecharlogD0.5[18/18.8] 0.5{deg} D-factor (3)GeV**2.cm**-5stat.fit.paramfloate_logD0.5[0.4/0.7] Negative uncertainty in logD0.5GeV**2.cm**-5stat.errorfloatE_logD0.5[0.4/0.6] Positive uncertainty in logD0.5GeV**2.cm**-5stat.error;stat.maxfloatf_logD0.5Flag on logD0.5 (2)meta.codecharJ/ApJ/857/145/table4Velocity and metallicity measurementsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMagLiteSOriginal MAGLITES identifier (JHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharRAJ2000[113.2/115] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-58.4/-57.3] Declination (J2000)degpos.eq.dec;meta.maing0mag[14.6/20.3] Dereddened DECam g band magnitude (1)magphot.mag;em.opt.Bfloatr0mag[13.9/20] Dereddened DECam r band magnitude (1)magphot.mag;em.opt.RfloatInstInstrument/Masks usedinstr.setupcharMJD[57777.7/57902.4] Modified Julian Date; JD-2400000.5dtime.epochfloatS/N[3.2/110.8] Spectra signal-to-noisestat.snrfloatHRV[-21.5/499] Heliocentric radial velocitykm/sspect.dopplerVeloc;pos.heliocentricfloate_HRV[0.5/15] Uncertainty in HRVkm/sstat.errorfloatEW[1.7/5.2]? Equivalent width, calcium triplet, in Angstrom units0.1nmspect.line.eqWidthfloatnullablee_EW[0.2/0.9]? Uncertainty in EW0.1nmstat.error;spect.line.eqWidthfloatnullable[Fe/H][-2.8/-1.9]? Metallicitylog(Sun)phys.abund.Zdoublenullablee_[Fe/H][0.1/0.5]? Uncertainty in [Fe/H]log(Sun)stat.error;phys.abund.FefloatnullableMm[0/3]? Membership (2)meta.code.memberintnullableSimbadSimbad column added by the CDSmeta.ref.urlchar