The Transverse velocity of the Andromeda system, derived from the M31 satellite population

Abstract

We present a dynamical measurement of the tangential motion of the Andromeda system, the ensemble consisting of the Andromeda Galaxy (M31) and its satellites. The system is modelled as a structure with cosmologically-motivated velocity dispersion and density profiles, and we show that our method works well when tested using the most massive substructures in high-resolution Lambda Cold Dark Matter simulations. Applied to the sample of 40 currently-known galaxies of this system, we find a value for the transverse velocity of 164.4 +/- 61.8 km/s (v_East = -111.5 +/- 70.2 km/s and v_North = 99.4 +/- 60.0 km/s), significantly higher than previous estimates of the proper motion of M31 itself. This result has significant implications on estimates of the mass of the Local Group, as well as on its past and future history.

10 pages, 5 figures, accepted for publication in MNRAS, replacement of one panel in Figure 5

References in corpus (9)

• A Vast Thin Plane of Co-rotating Dwarf Galaxies Orbiting the Andromeda Galaxy
• The M31 Velocity Vector. II. Radial Orbit Towards the Milky Way and Implied Local Group Mass
• The M31 Velocity Vector. I. Hubble Space Telescope Proper Motion Measurements
• M31 Transverse Velocity and Local Group Mass from Satellite Kinematics
• A dynamical model of the local cosmic expansion
• The Collision Between The Milky Way And Andromeda
• Stellar Kinematics in the Complicated Inner Spheroid of M31: Discovery of Substructure Along the Southeastern Minor Axis and its Relationship to the Giant Southern Stream
• The Proper Motion of the Local Group Galaxy IC 10
• Spectroscopy of the three distant Andromedan satellites Cassiopeia III, Lacerta I, and Perseus I

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