A Reanalysis of Small Scale Velocity Dispersion in the CfA1 Survey

Abstract

The velocity dispersion of galaxies on scales of $r\sim1h^{-1}$ Mpc, $\sigma_{12}(r)$, may be estimated from the anisotropy of the galaxy-galaxy correlation function in redshift space. We present a reanalysis of the CfA1 survey, correct an error in the original analysis of Davis and Peebles (1983), and find that $\sigma_{12}(r)$ is extremely sensitive to the details of how corrections for infall into the Virgo cluster are applied. We conclude that a robust value of $\sigma_{12}$ cannot be obtained from this survey. We also discuss results from other redshift surveys, including the effect of removing clusters.