An Estimate of m without Conventional Priors

Abstract

Using mean relative peculiar velocity measurements for pairs of galaxies, we estimate the cosmological density parameter Ωm and the amplitude of density fluctuations σ8. Our results suggest that our statistic is a robust and reproducible measure of the mean pairwise velocity and thereby the Ωm parameter. We get Ω m = 0.30-0.07-0.17 and σ8 = 1.13-0.230.22. 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.