The Pairwise Velocity Distribution Function of Galaxies in the LCRS,   2dF, and SDSS Redshift Surveys
  A comparison of the galaxy pairwise velocity distribution functions determined from the three largest publicly available galaxy redshift surveys is presented. This is the first direct comparison of this function across these surveys using an identical method. It is found that the two r-band selected surveys, the LCRS (Las Campanas Redshift Survey) and the SDSS (Sloan Digital Sky Survey), are in excellent agreement with 363 +/- 44 km/sec and 357 +/- 17 km/sec respectively. The b-band selected 2dF survey gives slightly lower results with 331 +/- 19 km/sec. This difference is expected given the sampling biases in the different surveys although it is not highly significant. These results and analysis of subsets of data indicate that the method is stable to singular features in each survey such as the prevalence of rich clusters. The technique utilizes a Fourier-space deconvolution of the redshift-space distortions in the correlation function in the sigma(rp)-pi basis, which has been previously described. This method returns the entire distribution function rather than just the second moment. In all cases the distribution function is well-characterized by an exponential. 
Stephen D. Landy