Balancing mass and momentum in the Local Group

  title={Balancing mass and momentum in the Local Group},
  author={Jonathan Diaz and Sergey E. Koposov and Michael J. Irwin and Vasily A Belokurov and Wyn Evans},
  journal={Monthly Notices of the Royal Astronomical Society},
In the rest frame of the Local Group (LG), the total momentum of the Milky Way (MW) and Andromeda (M31) should balance to zero. We use this fact to constrain new solutions for the solar motion with respect to the LG centre-of-mass, the total mass of the LG, and the individual masses of M31 and the MW. Using the set of remote LG galaxies at $>350$ kpc from the MW and M31, we find that the solar motion has amplitude $V_{\odot}=299\pm 15 {\rm ~km~s^{-1}}$ in a direction pointing toward galactic… Expand
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