The Pairwise Peculiar Velocity Dispersion of Galaxies: Effects of the Infall

We study the reliability of the reconstruction method which uses a modellingof the redshift distortions of the two-point correlation function to estimatethe pairwise peculiar velocity dispersion of galaxies. In particular, thedependence of this quantity on different models for the infall velocity isexamined for the Las Campanas Redshift Survey. We make extensive use ofnumerical simulations and of mock catalogs derived from them to discuss theeffect of a self-similar infall model, of zero infall, and of the real infalltaken from the simulation. The implications for two recent discrepantdeterminations of the pairwise velocity dispersion for this survey arediscussed.Comment: minor changes in the discussion; accepted for publication in ApJ; 8 pages with 2 figures include