Two effects largely define the evolution of spatial bias:

  Statistical (Peak) Bias. Dominates the bias at high redshifts. Produces Positive Bias (b>1). Strong dependence on mass of galaxies. Bias decreases with decreasing redshift.

Pair-wise Velocity bias (b=0.5-0.6) reflects mainly the spatial (anti)bias. It does NOT mean that galaxies move slower than the dark matter.

Galaxies in clusters move slightly faster
(b =1.1-1.3) than DM particles

Title Page

Spatial Bias

Velocity Bias