The cosmological mean density and its local variations probed by peculiar velocities

Peculiar velocities throughout the region of the Local Supercluster are reconstructed by two different orbitretracing methods. The requirement of optimal correlation between the radial components of reconstructed velocities and the observed peculiar velocities derived from our extensive new catalog of distances puts stringent constraints on the values of the cosmological parameters. Our constraints intersect those from studies of microwave background fluctuations and statistical properties of galaxy clustering: the ensemble of constraints is consistent with Omega(m) 0.22 +/- 0.02. While motions throughout the Local Supercluster provide a measure of the mean ratio of mass to light, there can be large local fluctuations. Our reconstruction of the infall velocities in the immediate vicinity of the Virgo Cluster shows that there is a mass-to-light anomaly of a factor of 3-6 between groups in the general field environment and the heavily populated Virgo Cluster.