Cosmic Flows 99: Conference Summary

Abstract

I address the following issues: All bulk velocity measurements (but one) are consistent with our standard gravitational instability theory. New accurate data and reconstruction methods allow high-resolution dynamical analysis nearby, revealing Virgo, Ursa Major and Fornax as attractors. Large peculiar-velocity surveys enable robust reconstruction of the dynamical fields on the Great-Attractor scale. A decomposition of the velocity field into its local and tidal components indicates the presence of big perturbations further away. Cluster velocities start exploring very large scales, revealing Coma, Shapely and other mass enhancements, and constraining a possible local Hubble bubble. Supernovae type Ia (SNIa) are very promising for cosmic flow analysis. Peculiar velocities do provide unique valuable constraints on cosmological parameters, e.g., 0.3<Omega_m<1 (95% confidence) independent of biasing. Jointly with other data they can confine other parameters such as Omega_Lambda, h, sigma_8, n, and the biasing. Nontrivial features of the biasing scheme can explain much of the span of estimates for beta. Quantitative error analysis is essential in our maturing field; every method ought to be calibrated with suitable mock catalogs, that are offered as benchmarks.