J/ApJ/855/43ivo://CDS.VizieR/J/ApJ/855/43doi:10.26093/cds/vizier.18550043CDSMedina G.E.Munoz R.R.Vivas A.K.Carlin J.L.Forster F.Martinez J.,Galbany L.Gonzalez-Gaitan S.Hamuy M.de Jaeger T.Maureira J.C.,Martin J.S.2019-12-10T06:35:00Z2018-12-10T08:22:36ZCDS support team

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

cds-question@unistra.frvariable-starsstellar-distancemilky-way-galaxyvisible-astronomybroad-band-photometryWe report the discovery of distant RR Lyrae stars, including the most distant known in the Milky Way, using data taken in the g-band with the Dark Energy Camera as part of the High cadence Transient Survey (HiTS; 2014 campaign). We detect a total of 173 RR Lyrae stars over a ~120deg^2^ area, including both known RR Lyrae and new detections. The heliocentric distances dH of the full sample range from 9 to >200kpc, with 18 of them beyond 90kpc. We identify three sub-groups of RR Lyrae as members of known systems: the Sextans dwarf spheroidal galaxy, for which we report 46 new discoveries, and the ultra-faint dwarf galaxies Leo IV and Leo V. Following an MCMC methodology, we fit spherical and ellipsoidal profiles of the form {rho}(R)~Rn to the radial density distribution of RR Lyrae in the Galactic halo. The best fit corresponds to the spherical case, for which we obtain a simple power-law index of n=-4.17_-0.20_^+0.18^, consistent with recent studies made with samples covering shorter distances. The pulsational properties of the outermost RR Lyrae in the sample (dH>90kpc) differ from the ones in the halo population at closer distances. The distribution of the stars in a period-amplitude diagram suggest they belong to Oosterhoff-intermediate or Oosterhoff II groups, similar to what is found in the ultra-faint dwarf satellites around the Milky Way. The new distant stars discovered represent an important addition to the few existing tracers of the Milky Way potential in the outer halo.2018ApJ...855...43Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/855/43CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/110/2166 : Variables in Sextans dSph galaxy (Mateo+ 1995)J/AJ/126/2840 : BVI CCD photometry of Sextans dSph galaxy (Lee+, 2003)J/AJ/127/1158 : QUEST RR Lyrae Survey first catalog (Vivas+, 2004)J/ApJS/162/1 : MUSYC: optical source catalog (Gawiser+, 2006)J/AJ/132/714 : QUEST RR Lyrae survey. II. Halo overdensities (Vivas+, 2006)J/ApJ/678/851 : RR Lyrae survey in the Galactic Halo (Keller+, 2008)J/MNRAS/398/1757 : RR Lyraes in SDSS stripe 82 (Watkins+, 2009)J/ApJ/708/717 : Light curve templates of RR Lyrae stars (Sesar+, 2010)J/ApJ/731/4 : Galactic halo as seen by the CFHTLS (Sesar+, 2011)J/ApJ/756/23 : V-band follow-up of RR Lyrae from SEKBO (Akhter+, 2012)J/AJ/144/4 : Dwarf galaxies in the Local Group (McConnachie+, 2012)J/ApJ/763/32 : Galactic halo RRab stars from CSS (Drake+, 2013)J/ApJ/765/154 : RR Lyrae stars in the Catalina Sky Survey (Drake+, 2013)J/AJ/146/101 : LINEAR. III. Periodic variables (Palaversa+, 2013)J/ApJ/776/26 : RRab stars in the Orphan stream distances (Sesar+, 2013)J/AJ/146/21 : LINEAR. II. Catalog of RR Lyrae stars (Sesar+, 2013)J/ApJS/213/9 : Catalina Surveys periodic variable stars (Drake+, 2014)J/ApJ/781/22 : La Silla QUEST RR Lyrae star survey --Region I (Zinn+, 2014)J/ApJ/788/105 : XSTPS RR Lyrae in the north Galactic cap (Faccioli+, 2014)J/ApJ/793/135 : Positions and distances of RR Lyrae stars (Sesar+, 2014)J/A+A/574/A15 : RR Lyrae in omega Cen (Fernandez-Trincado+, 2015)J/ApJ/829/108 : Kinematic data of Galactic globular clusters (Eadie+, 2016)J/MNRAS/460/30 : gi photometry of Sextans dSph galaxy stars (Roderick+, 2016)J/ApJ/831/165 : RR Lyrae as tracers in Virgo overdensity region (Vivas+, 2016)J/MNRAS/469/3688 : CSS Periodic Variable Star Catalogue (Drake+, 2017)J/ApJ/844/L4 : PS1 RRab for tracing outer Virgo overdensity (Sesar+, 2017)J/ApJ/849/150 : RR Lyrae candidates in the MW outer halo (Cohen+, 2017)J/AJ/153/179 : VVV Survey RR Lyr stars in Galactic plane (Minniti+, 2017)J/AJ/153/204 : RR Lyrae stars from the PS1 3{pi} survey (Sesar+, 2017)J/AJ/154/85 : CTIO/DECam photometry of RR Lyrae stars in M5 (Vivas+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/855/43https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/855/43http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/855/43https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/855/43https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/855/43http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/855/43GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/855/43/table1 (Most distant RR Lyrae stars (d_H_>90kpc))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/855/43/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/855/43/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/855/43/table1?GETtext/xml+votable180.050000true164.47577-0.434030.005555555555555556Cone search capability for table J/ApJ/855/43/table5 (RR Lyrae stars found in the Sextans dSph by the High Cadence Transient Survey (HiTS))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/855/43/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/855/43/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/855/43/table5?GETtext/xml+votable180.050000true152.06402-2.273690.005555555555555556Cone search capability for table J/ApJ/855/43/table6 (Full list of the RRLs presented in this work, excluding the candidates in the Sextans dSph galaxy)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/855/43/table6?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/855/43/table6?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/855/43/table6?GETtext/xml+votable180.050000true149.686162.521720.0055555555555555565/6765 6/26772 26781 26818 26826 26827 26831 26832 26841 26844 26845 26846 26851 26859 26860 26869 26871 26903 26907 26908 26909 26911 26917 26919 26926 26930 26931 26935 26937 26938 26947 26956 26958 26980 26982 26984 26991 26994 27000 27001 27002 27004 27008 27011 27015 27017 27021 27027 27032 27033 27035 27037 27038 27039 27053 27056 27059 27064 27066 27068 27078 27080 27082 27084 27200 27201 27205 27206 27207 27212 27213 27216 27218 27224 27239 27249 27254 27256 27258 27259https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/855/43?format=asciiOpticaldefaultJ/ApJ/855/43/table1Most distant RR Lyrae stars (d_H_>90kpc)DEJ2000[-10/2.3] Declination (J2000)degpos.eq.dec;meta.mainrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHiTSRR Lyrae identifier (HHMMSS+DDMMSS; J2000)meta.id;meta.maincharRAJ2000[155/173.3] Right ascension (J2000)degpos.eq.ra;meta.maingmagAvg[20.4/22.8] g-band mean AB magnitudemagphot.mag;em.opt.BfloatDist[92.5/262.2] Heliocentric distance (d_H_)kpcpos.distancefloate_Dist[4/24.3] Uncertainty in Distkpcstat.errorfloatTypeRR Lyrae type ("ab" or "c")meta.notecharNobs[18/22] Number of observationsmeta.numberintJ/ApJ/855/43/table5RR Lyrae stars found in the Sextans dSph by the High Cadence Transient Survey (HiTS)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHiTSRR Lyrae identifier (HHMMSS+DDMMSS; J2000)meta.id;meta.maincharRAJ2000[152/154.2] Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-2.6/-0.6] Declination (J2000)degpos.eq.dec;meta.maingmagAvg[20/20.6] g-band mean AB magnitudemagphot.mag;em.opt.BfloatPer[0.3/0.8] Perioddtime.perioddoubleAmp[0.4/1.2] Amplitudemagphot.magfloatDist[76/90] Heliocentric distance (d_H_)kpcpos.distanceintTypeRR Lyrae type ("ab" or "c")meta.notecharNobs[20/38] Number of observationsmeta.numberintpIDPrevious ID (1)meta.id.crosscharS17Display data from Sesar+, 2017, J/AJ/153/204 within 2"meta.ref.urlintnullableGaiaDisplay the Gaia-DR2 data (I/345) within 1"meta.ref.urlcharPS1Display the PS1 data (II/349) within 1"meta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlcharJ/ApJ/855/43/table6Full list of the RRLs presented in this work, excluding the candidates in the Sextans dSph galaxyrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDdisplay the uncertainty in distance (table 1) for this most distant RR Lyrae starmeta.codecharHiTSRR Lyrae identifier (HHMMSS+DDMMSS; J2000)meta.id;meta.maincharprimaryRAJ2000[149.6/174.5] Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-10/3.1] Declination (J2000)degpos.eq.dec;meta.maingmagAvg[15.5,22.8] g-band mean AB magnitudemagphot.mag;em.opt.BfloatPer[0.2/0.9] Perioddtime.periodfloatAmp[0.1/1.5] Amplitudemagphot.magfloatDist[9/262] Heliocentric distance (d_H_)kpcpos.distanceintTypeRR Lyrae type ("ab" or "c")meta.notecharNobs[16/38] Number of observationsmeta.numberintS17Display data from Sesar+, 2017, J/AJ/153/204 within 2"meta.ref.urlintnullableGaiaDisplay the Gaia-DR2 data (I/345) within 1"meta.ref.urlcharPS1Display the PS1 data (II/349) within 1"meta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar