J/ApJ/866/22ivo://CDS.VizieR/J/ApJ/866/22doi:10.26093/cds/vizier.18660022CDSLi T.S.Simon J.D.Kuehn K.Pace A.B.Erkal D.Bechtol K.Yanny B.,Drlica-Wagner A.Marshall J.L.Lidman C.Balbinot E.Carollo D.,Jenkins S.Martinez-Vazquez C.E.Shipp N.Stringer K.M.Vivas A.K.,Walker A.R.Wechsler R.H.Abdalla F.B.Allam S.Annis J.Avila S.,Bertin E.Brooks D.Buckley-Geer E.Burke D.L.Carnero Rosell A.,Carrasco Kind M.Carretero J.Cunha C.E.D'Andrea C.B.da Costa L.N.,Davis C.De Vicente J.Doel P.Eifler T.F.Evrard A.E.Flaugher B.,Frieman J.Garcia-Bellido J.Gaztanaga E.Gerdes D.W.Gruen D.,Gruendl R.A.Gschwend J.Gutierrez G.Hartley W.G.Hollowood D.L.,Honscheid K.James D.J.Krause E.Maia M.A.G.March M.Menanteau F.,Miquel R.Plazas A.A.Sanchez E.Santiago B.Scarpine V.Schindler R.,Schubnell M.Sevilla-Noarbe I.Smith M.Smith R.C.Soares-Santos M.,Sobreira F.Suchyta E.Swanson M.E.C.Tarle G.Tucker D.L.2021-02-23T12:24:08Z2019-10-23T12:51:10ZCDS support team

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

cds-question@unistra.frgalaxiesspectroscopyradial-velocityline-intensitiesmetallicityphotometryvisible-astronomyWe present a spectroscopic study of the tidal tails and core of the Milky Way satellite Tucana III, collectively referred to as the Tucana III stream, using the 2dF+AAOmega spectrograph on the Anglo-Australian Telescope and the IMACS spectrograph on the Magellan Baade Telescope. In addition to recovering the brightest nine previously known member stars in the Tucana III core, we identify 22 members in the tidal tails. We observe strong evidence for a velocity gradient of 8.0+/-0.4km/s/deg over at least 3{deg} on the sky. Based on the continuity in velocity, we confirm that the Tucana III tails are real tidal extensions of Tucana III. The large velocity gradient of the stream implies that Tucana III is likely on a radial orbit. We successfully obtain metallicities for four members in the core and 12 members in the tails. We find that members close to the ends of the stream tend to be more metal-poor than members in the core, indicating a possible metallicity gradient between the center of the progenitor halo and its edge. The spread in metallicity suggests that the progenitor of the Tucana III stream is likely a dwarf galaxy rather than a star cluster. Furthermore, we find that with the precise photometry of the Dark Energy Survey data, there is a discernible color offset between metal-rich disk stars and metal-poor stream members. This metallicity-dependent color offers a more efficient method to recognize metal-poor targets and will increase the selection efficiency of stream members for future spectroscopic follow-up programs on stellar streams.2018ApJ...866...22Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/866/22CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/337 : Gaia DR1 (Gaia Collaboration, 2016)J/AJ/135/2177 : High proper motion stars in the DSS. IV. (Lepine, 2008)J/MNRAS/397/1748 : Spectroscopic study of Segue 2 (Belokurov+, 2009)J/ApJ/704/898 : Photometry of the Hercules dwarf galaxy (Sand+, 2009)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/ApJ/756/121 : Variable stars in Her dwarf galaxy (Musella+, 2012)J/ApJ/756/79 : Opt. photom. in 3 Local Group dwarf galaxies (Sand+, 2012)J/MNRAS/434/1681 : Extremely metal-poor stars CaII triplet (Carrera+, 2013)J/ApJ/770/16 : Spectroscopic members of Segue 2 galaxy (Kirby+, 2013)J/AJ/145/102 : Sp. of bright M dwarfs in northern sky (Lepine+, 2013)J/A+A/570/A61 : PM-selected stars of Hercules galaxy (Fabrizio+, 2014)J/ApJ/808/95 : Spectroscopy of Reticulum II (Simon+, 2015)J/ApJ/819/1 : Wide-field photometry of the GC Palomar 5 (Ibata+, 2016)J/ApJ/838/44 : Abundances of the Tuc III brightest members (Hansen+, 2017)J/ApJ/842/120 : Large sp. survey of Palomar 5 stellar stream (Ibata+, 2017)J/ApJ/838/11 : Member stars in the MW satellite Tucana III (Simon+, 2017)J/ApJ/857/145 : MagLiteS Carina II and Carina III spectroscopy (Li+, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/866/22https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/866/22http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/866/22https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/866/22https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/866/22http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/866/22GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/866/22/table1 (Velocity and metallicity measurements of the observed stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/866/22/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/866/22/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/866/22/table1?GETtext/xml+votable180.050000true355.83288-59.427990.005555555555555556Cone search capability for table J/ApJ/866/22/table3 (Potential members in the Tuc III stream)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/866/22/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/866/22/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/866/22/table3?GETtext/xml+votable180.050000true354.99128-59.621740.0055555555555555566/34858 34859 34944 34945 34946 46101 46102 46103 46108 46109 46144 46145 46146https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/866/22?format=asciiOpticaldefaultJ/ApJ/866/22/table1Velocity and metallicity measurements of the observed starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSet[0/3]? Subset (1)meta.noteintnullableDESIdentifier, Jhhmmss.ss-ddmmss.s (G1)meta.id;meta.maincharRAJ2000Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-60.4/-58.8] Declination (J2000)degpos.eq.dec;meta.maingmag[15.9/21.1] Dereddened g band PSF magnitude (G2)magphot.mag;em.opt.Bfloatrmag[15/20.5] Dereddened r band PSF magnitude (G2)magphot.mag;em.opt.RfloatCatEither DES DR1 or Y2Q catalog (G2)meta.notecharInstTelescope/instrument (G3)meta.notecharSNR[4.1/237.3] Average spectra signal-to-noise ratiostat.snr;stat.meanfloatHRV[-326/430] Heliocentric Radial Velocitykm/sspect.dopplerVeloc;pos.heliocentricfloate_HRV[0.5/6.5] Uncertainty in HRVkm/sstat.errorfloatEW[1.2/8.4]? Equivalent Width, Angstroms0.1nmspect.line.eqWidthfloatnullablee_EW[0.2/1.6]? Uncertainty in EW0.1nmstat.error;spect.line.eqWidthfloatnullable[Fe/H][-3/-2.2]? Metallicityphys.abund.Zfloatnullablee_[Fe/H][0.1/0.6]? Uncertainty in [Fe/H]stat.error;phys.abund.FefloatnullableMm[0/1]? Subjective membership (1:member; 0:non-member) (2)meta.code.memberintnullableProb? Membership probability, objective mixture model (3)%statfloatnullableCommCommentmeta.notecharS17Display data from Simon+, 2017, J/ApJ/838/11, within 1"meta.ref.urlintnullableSimbadSimbad column added by the CDSmeta.ref.urlcharJ/ApJ/866/22/table3Potential members in the Tuc III streamrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDESIdentifier, Jhhmmss.ss-ddmmss.s (G1)meta.id;meta.maincharRAJ2000Right Ascension, decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000[-60.3/-59] Declination, decimal degrees (J2000)degpos.eq.dec;meta.maingmag[18.7/21.6] Dereddened g band PSF magnitude (G2)magphot.mag;em.opt.Bfloatrmag[18.3/21.3] Dereddened r band PSF magnitude (G2)magphot.mag;em.opt.RfloatCatEither DR1 or Y2Q catalog (G2)meta.notecharInstTelescope/instrument (G3)meta.notecharSNR[1.6/6.7] Spectra Signal-to-noise ratio atstat.snrfloatHRV[-137.1/-71] Heliocentric Radial Velocity (1)km/sspect.dopplerVeloc;pos.heliocentricfloat