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Paper: The dynamics of the Local Group and the mass of the Galaxy
Volume: 10, Evolution of the Universe of Galaxies: Edwin Hubble Centennial Symposium
Page: 51
Authors: Zaritsky, Dennis
Abstract: Timing arguments using Leo I, M31, and more distant members of the Local Group are all in agreement and imply that the Galaxy has a mass not less than 13 x 10 exp 11 solar masses for an adopted age of the universe of 14 Gyr and an M31/Milky Way mass ratio of 1.8. The 'best-fit' models of the remote Local Group members imply either that there is a Local Group dark matter halo of roughly 20 x 10 exp 11 solar masses out to radii of 1 Mpc, or that the mass of the Milky Way is not less than 17.5 x 10 exp 11 solar masses. If the Milky Way has a mass of 17.5 x 10 exp 11 solar masses, the M31-Milky Way timing arguments can only be satisfied if the Milky Way has a tangential velocity component with respect to M31 of approximately 55 km/s.
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