Velocity Fields from Iras–pscz Survey

We present a self–consistent nonparametric model of the cosmic velocity field based on the spatial distribution of IRAS galaxies in the recently completed all–sky PSCz redshift survey. The dense sampling of PSCz galaxies allows us to infer peculiar velocities field up to large distances with unprecedented high resolution. The most streaking feature of the PSCz model velocity field is a coherent large–scale streaming motion along the Perseus Pisces, Local Supercluster, Great Attractor and Shapley Concentration baseline, with no evidence for a backinfall into the Great Attractor region. Instead, material behind and around the Great Attractor in inferred to be streaming towards the Shapley Concentration. A likelihood analysis that uses the information available on bulk velocities, cosmological dipoles and local shear has been performed to measure β. We have obtained β = 0.6 −0.15 (1–σ), in agreement with other recent determinations.