The large-scale distribution of IRAS galaxies and the predicted peculiar velocity field

Using the QDOT IRAS galaxy redshift survey, a smoothed density field is constructed, corrected for peculiar velocity distortion, of a region of the local universe out to ∼ 150 h −1 Mpc. Predicted peculiar velocities are calculated from this density field, assuming gravitational instability theory, and compared to observed velocities derived from Tully-Fisher and D n −σ techniques. A good correlation is seen. If IRAS galaxies trace the mass on large scales then the universe must have a density very close to the critical value.