J/ApJ/875/77ivo://CDS.VizieR/J/ApJ/875/77doi:10.26093/cds/vizier.18750077CDSPace A.B.Li T.S.2022-09-05T12:40:21Z2020-10-09T12:55:21ZCDS support team

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

cds-question@unistra.frgalaxiesphotometryproper-motionsinfrared-photometryvisible-astronomyWe present a new, probabilistic method for determining the systemic proper motions of Milky Way (MW) ultra-faint satellites in the Dark Energy Survey (DES). We utilize the superb photometry from the first public data release (DR1) of the DES to select candidate members and cross-match them with the proper motions from the Gaia DR2. We model the candidate members with a mixture model (satellite and MW) in spatial and proper motion space. This method does not require prior knowledge of satellite membership and can successfully determine the tangential motion of 13 DES satellites. With our method, we present measurements of the following satellites: Columba I, Eridanus III, Grus II, Phoenix II, Pictor I, Reticulum III, and Tucana IV. This is the first systemic proper motion measurement for several of these satellites, and the majority lack extensive spectroscopic follow-up studies. We compare these to the predictions of Large Magellanic Cloud satellites and the vast polar structure. With the high-precision DES photometry, we conclude that most of the newly identified member stars are very metal-poor ([Fe/H]<=-2), similar to other ultra-faint dwarf galaxies, while Reticulum III is likely more metal-rich. We also find potential members in the following satellites that might indicate their overall proper motion: Cetus II, Kim 2, and Horologium II. However, due to the small number of members in each satellite, spectroscopic follow-up observations are necessary to determine the systemic proper motion in these satellites.2019ApJ...875...77Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/875/77CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/357 : The Dark Energy Survey (DES): Data Release 1 (Abbott+, 2018)I/345 : Gaia DR2 (Gaia Collaboration, 2018)J/AJ/144/4 : Dwarf galaxies in the Local Group (McConnachie+, 2012)J/ApJ/770/16 : Spectroscopic members of Segue 2 galaxy (Kirby+, 2013)J/ApJ/779/102 : Metallicities of RGB stars in dwarf galaxies (Kirby+, 2013)J/ApJ/803/63 : gr photometry of stars in Kim 2 (Kim+, 2015)J/ApJ/808/95 : Spectroscopy of Reticulum II (Simon+, 2015)J/ApJ/808/108 : M2FS stellar spectroscopy of Reticulum 2 (Walker+, 2015)J/ApJ/819/53 : Magellan/M2FS spectrosc. of Tucana 2 & Grus 1 (Walker+, 2016)J/ApJ/838/11 : Member stars in the MW satellite Tucana III (Simon+, 2017)J/ApJ/857/74 : Abundances of 7 new member stars in Tucana II (Chiti+, 2018)J/A+A/616/A12 : Gaia DR2 sources in GC and dSph (Gaia Collaboration+, 2018)J/ApJ/866/22 : Spectroscopic analysis of Tuc III stream (Li+, 2018)J/ApJ/857/145 : MagLiteS Carina II and Carina III spectroscopy (Li+, 2018)J/A+A/620/A155 : Gaia proper motions of 7 UFD galaxies (Massari+, 2018)J/ApJ/863/25 : Deep Magellan obs. of 4 MW satellites (Mutlu-Pakdil+, 2018)J/ApJ/852/99 : Abundances of 3 metal-poor stars in Hor I (Nagasawa+, 2018)J/ApJ/863/89 : Gaia PMs of stars in ultra-faint MW satellites (Simon, 2018)J/A+A/623/A129 : New satellites of the LMC search (Fritz+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/875/77https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/875/77http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/875/77https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/875/77https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/875/77http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/875/77GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/875/77/table1 (Properties of the DES satellites)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/875/77/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/875/77/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/875/77/table1?GETtext/xml+votable180.050000true19.47-17.420.005555555555555556Cone search capability for table J/ApJ/875/77/table4 (Proper motion members from the likelihood fit with membership probability p_i_>0.1)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/875/77/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/875/77/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/875/77/table4?GETtext/xml+votable180.050000true56.08660194-43.541013060.0055555555555555566/16735 17872 20664 33257 33259 33625-33627 33685 33720 33745 33995 33998 34365-34366 34856 34858 34944 34946 35347 46021 46089 46101 46126-46127 46144-46145 46169 46209 46212-46213 46279 46290 46620-46621 46623 474251.9867573869263685e-19 3.916500758235022e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/875/77?format=asciiOpticalInfrareddefaultJ/ApJ/875/77/table1Properties of the DES satellitesSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNsNumber of stars for this satellite (link to Table 4)meta.numberintnullableNameSatellite namemeta.id;meta.maincharf_Name[ab] Flag on Name (1)meta.codecharRAJ2000Right ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainah[0.2/13] Semimajor half-light radius (a_h_)arcminphys.angSizefloatell[0.12/0.7]? Ellipticity {epsilon}src.ellipticityfloatnullablePA[4/164]? Position angle {theta}degpos.posAngintnullableDist[23.8/366] Heliocentric distancekpcpos.distancefloatVMag[-7.1/0] V-band absolute magnitudemagphot.magfloatRefReference(s) (2)meta.ref;pos.framecharIDAbbreviated ID as given in Table 4; column added by CDSmeta.idcharprimarypmRA[-1.1/2.4]? Systemic proper motion in {alpha}cos{delta} direction (from Table 3)mas/yrpos.pm;pos.eq.rafloatnullablee_pmRA[0.04/0.4]? Negative uncertainty in pmRAmas/yrstat.error;pos.pm;pos.eq.rafloatnullableE_pmRA[0.04/0.5]? Positive uncertainty in pmRAmas/yrstat.error;stat.maxfloatnullablepmDE[-1.8/0.2]? Systemic proper motion in {delta} direction (from Table 3)mas/yrpos.pm;pos.eq.decfloatnullablee_pmDE[0.04/0.8]? Negative uncertainty in pmDEmas/yrstat.error;pos.pm;pos.eq.decfloatnullableE_pmDE[0.04/0.7]? Positive uncertainty in pmDEmas/yrstat.error;stat.maxfloatnullableJ/ApJ/875/77/table4Proper motion members from the likelihood fit with membership probability p_i_>0.1recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDDwarf galaxy identifiermeta.id.parentcharCoadID[71227237/618443422] DES DR1 identifier (1)meta.id.crosslongGaiaGaia DR2 identifiermeta.id;meta.mainRA_ICRSGaia DR2 right ascension (ICRS) at Ep=2015.5degpos.eq.ra;meta.mainDE_ICRS[-61.4/-17.3] Gaia DR2 declination (ICRS) at Ep=2015.5degpos.eq.dec;meta.maingmag0avg[16/21.6] Dereddened weighted average g band (AB) magnitude (2)magphot.mag;em.opt.Bfloatrmag0avg[15.3/20.9] Dereddened weighted average r band (AB) magnitude (2)magphot.mag;em.opt.Rfloatimag0avg[15/21.2] Dereddened weighted average i band (AB) magnitude (2)magphot.mag;em.opt.IfloatGmag[15.4/21] Apparent Gaia band magnitude (3)magphot.mag;em.optfloatpmRA[-6.7/9.8] Proper motion along RA times cosDEmas/yrpos.pm;pos.eq.rafloate_pmRA[0.04/4.6] Uncertainty in pmRAmas/yrstat.error;pos.pm;pos.eq.rafloatpmDE[-7.7/6.5] Proper motion along DEmas/yrpos.pm;pos.eq.decfloate_pmDE[0.05/4.8] Uncertainty in pmDEmas/yrstat.error;pos.pm;pos.eq.decfloatPi[0.1/1] Membership probabilitymeta.code.memberfloatMP[-1/1]? Metallicity assessment (4)meta.codeintnullableSimbadSimbad column added by the CDSmeta.ref.urlchar_RA.icrsRight ascension (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.decnullableindexed