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dc.contributor.authorBanik, Indranil
dc.contributor.authorZhao, Hongsheng
dc.date.accessioned2017-10-17T10:30:14Z
dc.date.available2017-10-17T10:30:14Z
dc.date.issued2018-01
dc.identifier.citationBanik , I & Zhao , H 2018 , ' A plane of high-velocity galaxies across the Local Group ' , Monthly Notices of the Royal Astronomical Society , vol. 473 , no. 3 , pp. 4033-4054 . https://doi.org/10.1093/mnras/stx2596en
dc.identifier.issn0035-8711
dc.identifier.otherPURE: 251291777
dc.identifier.otherPURE UUID: cbaab4ef-63e2-4667-9199-3c689d493ec5
dc.identifier.otherScopus: 85046099085
dc.identifier.otherORCID: /0000-0002-4123-7325/work/39245052
dc.identifier.otherWOS: 000423809400088
dc.identifier.urihttps://hdl.handle.net/10023/11862
dc.description.abstractWe recently showed that several Local Group (LG) galaxies have much higher radial velocities (RVs) than predicted by a 3D dynamical model of the standard cosmological paradigm. Here, we show that six of these seven galaxies define a thin plane with root mean square thickness of only 101 kpc despite a widest extent of nearly 3 Mpc, much larger than the conventional virial radius of the Milky Way (MW) or M31. This plane passes within ∼70 kpc of the MW–M31 barycentre and is oriented so the MW–M31 line is inclined by 16° to it. We develop a toy model to constrain the scenario whereby a past MW–M31 flyby in Modified Newtonian Dynamics (MOND) forms tidal dwarf galaxies that settle into the recently discovered planes of satellites around the MW and M31. The scenario is viable only for a particular MW–M31 orbital plane. This roughly coincides with the plane of LG dwarfs with anomalously high RVs. Using a restricted N-body simulation of the LG in MOND, we show how the once fast-moving MW and M31 gravitationally slingshot test particles outwards at high speeds. The most distant such particles preferentially lie within the MW–M31 orbital plane, probably because the particles ending up with the highest RVs are those flung out almost parallel to the motion of the perturber. This suggests a dynamical reason for our finding of a similar trend in the real LG, something not easily explained as a chance alignment of galaxies with an isotropic or mildly flattened distribution (probability = 0.0015).
dc.format.extent22
dc.language.isoeng
dc.relation.ispartofMonthly Notices of the Royal Astronomical Societyen
dc.rights© 2017, the Author(s). This work has been made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.1093/mnras/stx2596en
dc.subjectGravitationen
dc.subjectGalaxy: discen
dc.subjectGalaxy: kinematics and dynamicsen
dc.subjectGalaxies: distances and redshiftsen
dc.subjectLocal Groupen
dc.subjectDark matteren
dc.subjectQB Astronomyen
dc.subjectQC Physicsen
dc.subjectAstronomy and Astrophysicsen
dc.subjectNDASen
dc.subjectBDCen
dc.subject.lccQBen
dc.subject.lccQCen
dc.titleA plane of high-velocity galaxies across the Local Groupen
dc.typeJournal articleen
dc.description.versionPostprinten
dc.contributor.institutionUniversity of St Andrews. School of Physics and Astronomyen
dc.identifier.doihttps://doi.org/10.1093/mnras/stx2596
dc.description.statusPeer revieweden
dc.identifier.urlhttps://academic.oup.com/mnras/article/doi/10.1093/mnras/stx2596/4411820/A-Plane-of-High-Velocity-Galaxies-Across-the-Local?guestAccessKey=7a7e184a-6b06-4b64-901c-e0c2d07c9621en


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