Confirmation of a large-scale, large-amplitude flow in the direction of the great attractor

New spectroscopy and photometry have been obtained for 136 elliptical and S0 galaxies in the direction of the large-scale streaming flow described by Dressler et al. and Lynden-Bell et al. These data are used with the D-n-sigma relation to predict distances for these galaxies, and, by comparison with their observed radial velocities, to predict their peculiar motions relative to a smooth Hubble flow. In excellent agreement with the earlier work, we find a gradually rising, coherent flow in the direction of the Hydra-Centaurus supercluster out to a distance of similar to 3000 km s(-1) with an average flow velocity of similar to 1000 km s(-1) with respect to the frame defined by the cosmic background radiation. The peculiar motions are then seen to decrease to near zero by a distance of similar to 4000 km s(-1). This is in general agreement with the model proposed by Lynden-Bell et al., which ascribes the flow to the gravitational pull of a "great attractor," a large, extended overdensity centered at approximately that distance. The new data offer some evidence for infall from the backside of the great attractor, but are inconclusive because of the small number of galaxies measured and uncertainties in the sign and magnitude of the Malmquist-like bias. The confirmation of the large-scale, large-amplitude flow reinforces an apparent contradiction with predictions of the velocity field in this region of space made with the IRAS galaxy sample and continues to provide a challenge for models of the formation of structure based on hot or cold dark matter.