Reconstructing the Peculiar Velocity of the Local Group with Modified
  Gravity and 2MASS
  The peculiar velocity of the Local Group, reconstructed from inhomogeneities
in the local density field, differs in direction and magnitude from the
velocity inferred from the Cosmic Microwave Background dipole. We investigate
whether generalized theories of gravity, which predict a modified growth of
perturbations, are able to alleviate this discrepancy. We introduce a general
formalism for calculating the real-space peculiar-velocity field for modified
gravity and theories with interactions in the dark sector. For different
classes of theories - scalar tensor and higher-dimensional gravity - we
reconstruct the Local Group peculiar velocity using groups of galaxies
identified in the 2MASS Redshift Survey. We show that, for realistic
parameters, modifications to General Relativity cannot account for the angular
discrepancy between the reconstructed Local Group velocity and the dipole in
the Cosmic Microwave Background.
