An estimate of Ωm without conventional priors

Using mean relative peculiar velocity measurements for pairs of galaxies, we estimate the cosmological density parameter Omega(m) and the amplitude of density fluctuations sigma(8). Our results suggest that our statistic is a robust and reproducible measure of the mean pairwise velocity and thereby the Omega(m) parameter. We get Omega(m) = 0.30(-0.07)(+0.17) and sigma(8) = 1.13(-0.23)(+0.22) These estimates do not depend on prior assumptions on the adiabaticity of the initial density fluctuations, the ionization history, or the values of other cosmological parameters.