The peculiar velocity of the Local Group - III. Dipole, quadrupole and infall solutions.

Utilizing our all-sky survey of spiral galaxies, we have derived a basic description of the extragalactic peculiar velocity field. In agreement with the results of previous authors, highly significant dipole and quadrupole terms are found. These are interpreted using a number of physically simple, but plausible models. No single attractor is able to explain all the motions observed in nearby galaxies, but the region surrounding the Centaurus cluster appears to have the dominant effect. We propose that the Lynden-Bell et al. 'Great Attractor' is in fact this region. We find that Virgocentric infall is smaller than previously assumed (150+/-60 km s^-1^). However, externally induced tidal shear provides additional retardation of the Hubble flow in this direction, raising the total peculiar velocity of the Local Group relative to Virgo to 340+/-70 km s^-1^, in fair agreement with the value 225+/-81 km s^-1^ derived from the independent Virgo-Coma distance-ratio method. A preliminary search in other regions shows that there is a significant infall of galaxies towards the northern end of the Perseus supercluster.