EVIDENCE FOR LARGE-SCALE STRUCTURE ON SCALES APPROXIMATELY-300 H-1 MPC

We have analysed the combined Abell-ACO cluster catalogue with m10 less-than-or-equal-to 16.4 which is 80 per cent redshift complete. Taking into account different models of the extinction region we find the cluster dipole pointing within less-than-or-equal-to 10-degrees of the CMB dipole direction which indicates that clusters are tracers of mass. The dipole amplitude converges at approximately 150 h-1 Mpc, within the completeness limit of the catalogue. We find that the anisotropy which is responsible for the LG motion with respect to the CMB rest frame extends in depth and has a scalelength of approximately 300 h-1 Mpc. Most of the Local Group peculiar velocity is induced by matter fluctuations within approximately 50 h-1 Mpc. Shapley's concentration (otherwise known as 'Giant Attractor' or 'alpha region') at a depth of approximately 140 h-1 Mpc, is responsible for less-than-or-equal-to 20 per cent of the Local Group's peculiar velocity. Finally, using linear perturbation theory, we find that OMEGA-0 less-than-or-equal-to 0.3