Biased Estimates of Ωm from Comparing Smoothed Predicted Velocity Fields to Unsmoothed Peculiar-Velocity Measurements

  title={Biased Estimates of $\Omega$m from Comparing Smoothed Predicted Velocity Fields to Unsmoothed Peculiar-Velocity Measurements},
  author={Andreas A. Berlind and Vijay K. Narayanan and David H. Weinberg The Ohio State University and Princeton University.},
  journal={The Astrophysical Journal},
We show that a regression of unsmoothed peculiar velocity measurements against peculiar velocities predicted from a smoothed galaxy density field leads to a biased estimate of the cosmological density parameter Ωm, even when galaxies trace the underlying mass distribution, and galaxy positions and velocities are known perfectly. The bias arises because the errors in the predicted velocities are correlated with the predicted velocities themselves. We investigate this bias using cosmological N… 

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