Peculiar velocities in the local Universe: comparison of different models and the implications for $H_0$ and dark matter

Understand

When measuring the value of the Hubble parameter, $H_0$, it is necessary to know the recession velocity free of the effects of peculiar velocities.

• In this work, we study different models of peculiar velocity in the local Universe.
• In particular, we compare models based on density reconstruction from galaxy redshift surveys and kernel smoothing of peculiar velocity data.
• The velocity field from the density reconstruction is obtained using the 2M++ galaxy redshift compilation, which is compared to two adaptive kernel-smoothed velocity fields: the first obtained from the 6dF Fundamental Plane sample and the other using a Tully-Fisher catalogue obtained by combining SFI++ and 2MTF.