Large-scale velocity fields as a test of cosmological models

It has been suggested that the Hubble expansion on large scales is distorted by bulk matter flows of surprisingly large amplitude. Using Bayesian statistics of conditional probability, the authors show that a high amplitude for large-scale matter flows can be used to rule out both hot dark matter and cold dark matter models of the growth of structure in the Universe. If the Universe is dominated by cold dark matter and galaxies are a biased mass tracer, then the bulk velocity on this scale should not exceed 150 km s-1. (author)