Cosmological parameters from the comparison of peculiar velocities with
  predictions from the 2M++ density field
  Peculiar velocity measurements are the only tool available in the
low-redshift Universe for mapping the large-scale distribution of matter and
can thus be used to constrain cosmology. Using redshifts from the 2M++ redshift
compilation, we reconstruct the density of galaxies within 200 Mpc/h, allowing
for the first time good sampling of important superclusters such as the Shapley
Concentration. We compare the predicted peculiar velocities from 2M++ to
Tully-Fisher and SNe peculiar velocities. We find a value of $\beta^* \equiv
\Omega_{\rm{m}}^{0.55}/b^* = 0.431 \pm 0.021$, suggesting
$\Omega_{\rm{m}}^{0.55}\sigma_{\rm{8,lin}} = 0.401 \pm 0.024$, in good
agreement with other probes. The predicted peculiar velocity of the Local Group
arising from the 2M++ volume alone is $540 \pm 40$ km/s, towards $l = 268 \pm
4, b= 38 \pm 6$, only $10^\circ$ out of alignment with the Cosmic Microwave
Background dipole. To account for velocity contributions arising from sources
outside the 2M++ volume, we fit simultaneously for $\beta^*$ and an external
bulk flow in our analysis. We find that an external bulk flow is preferred at
the 5.1$\sigma$ level, and the best fit has a velocity of $159\pm23$ km/s
towards $l=304 \pm 11, b = 6 \pm 13$. Finally, the predicted bulk flow of a 50
Mpc/h Gaussian-weighted volume centred on the Local Group is $230 \pm 30$ km/s,
in the direction $l=293\pm 8, b = 14 \pm 10$, in agreement with predictions
from $\Lambda$CDM.
