J/ApJ/844/L4ivo://CDS.VizieR/J/ApJ/844/L4doi:10.26093/cds/vizier.18449004CDSSesar B.Hernitschek N.Dierickx M.I.P.Fardal M.A.Rix H.-W.2019-05-02T08:29:07Z2018-04-17T10:37:42ZCDS support team

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

cds-question@unistra.frvariable-starsphotometrystellar-distancevisible-astronomyWe report the detection of spatially distinct stellar density features near the apocenters of the Sagittarius (Sgr) stream's main leading and trailing arm. These features are clearly visible in a high-fidelity stellar halo map that is based on RR Lyrae from Pan-STARRS1: there is a plume of stars 10kpc beyond the apocenter of the leading arm, and there is a "spur" extending to 130kpc, almost 30kpc beyond the previously detected apocenter of the trailing arm. Such an apocenter substructure is qualitatively expected in any Sgr stream model, as stars stripped from the progenitor at different pericenter passages become spatially separated there. The morphology of these new Sgr stream substructures could provide much-needed new clues and constraints for modeling the Sgr system, including the level of dynamical friction that Sgr has experienced. We also report the discovery of a new, presumably unrelated halo substructure at 80kpc from the Sun and 10{deg} from the Sgr orbital plane, which we dub the outer Virgo overdensity.2017ApJ...844L...4Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/844/L4CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/349 : The Pan-STARRS release 1 (PS1) Survey - DR1 (Chambers+, 2016)J/AJ/136/1645 : Spectroscopy of bright QUEST RR Lyrae stars (Vivas+, 2008)J/ApJ/691/306 : Photom. of RR Lyrae candidates in Virgo stream (Prior+, 2009)J/ApJ/708/717 : Light curve templates of RR Lyrae stars (Sesar+, 2010)J/ApJ/765/154 : RR Lyrae stars in the Catalina Sky Survey (Drake+, 2013)J/ApJ/817/73 : QSOs and RR Lyrae in Pan-STARRS1 3{pi} Data (Hernitschek+ 2016)J/ApJ/831/165 : RR Lyrae as tracers in Virgo overdensity region (Vivas+, 2016)J/AJ/153/204 : RR Lyrae stars from the PS1 3{pi} survey (Sesar+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/844/L4https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/844/L4http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/844/L4https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/844/L4https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/844/L4http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/844/L4GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/844/L4/table1 (Outer Virgo overdensity (outer VOD) PS1 RR Lyrae stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/844/L4/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/844/L4/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/844/L4/table1?GETtext/xml+votable180.050000true197.65117-8.205770.0055555555555555565/6430 6457 6/25679 25680 25683 25687 25692 25693 25694 25697 25701 25706 25713 25714 25715 25717 25718 25719 25726 25727 25755 25756 25758 25777 25793 25795 25796 25804 25805 25806 25808 25809 25811 25815 25816 25817 25819 25832 25837 25841 25844 25846 25864 25866 25870 25871 25873 25874 25875 25880 25889 25894 25897 25984 44970https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/844/L4?format=asciiOpticaldefaultJ/ApJ/844/L4/table1Outer Virgo overdensity (outer VOD) PS1 RR Lyrae starsPer[0.4/0.8] Perioddtime.perioddoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000[197.6/217.6] Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-11.2/-2.1] Declination (J2000)degpos.eq.dec;meta.mainScore[0.8/1] Final RRab classification score (1)meta.code.qualfloatDM[19/19.9] Distance modulus (2)magphot.mag.distModfloatPhi0[-0.5/0.5] Phase offset (3)dtime.phasedoublerAmp[0.2/1.2] PS1 r-band light curve amplitudemagsrc.var.amplitudefloatPS1Display the Pan-STARRS DR1 data (II/349) within 0.5"meta.ref.urlcharS17Display the RR Lyrae data from Sesar+, 2017, J/AJ/153/204, within 0.5"meta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar