The Velocity Field of Clusters of Galaxies within 100 Megaparsecs. II. Northern Clusters

May 1993 • 1993ApJ...409...14M

Authors • Mould, J. R. • Akeson, R. L. • Bothun, G. D. • Han, M. • Huchra, J. P. • Roth, J. • Schommer, R. A.

Abstract • Distances and peculiar velocities for galaxies in eight clusters and groups have been determined by means of the near-infrared Tully-Fisher relation. With the possible exception of a group halfway between us and the Hercules Cluster, we observe peculiar velocities of the same order as the measuring errors of ~400 km s^-1^. This result is consistent with the earlier Arecibo study by Aaronson and coworkers. The present sample is drawn from the northern galactic hemisphere and delineates a quiet region in the Hubble flow. This contrasts with the large-scale flows seen in the Hydra-Centaurus and Perseus-Pisces regions. We compare the observed peculiar velocities with predictions based upon the gravity field inferred from the IRAS redshift survey. The differences between the observed and predicted peculiar motions are generally small, except near dense structures, where the observed motions exceed the predictions by significant amounts. Kinematic models of the velocity field are also compared with the data. We cannot distinguish between parameterized models with a great attractor or models with a bulk flow.

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Rachel Akeson

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