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The Motions of Clusters of Galaxies and the Dipoles of the Peculiar Velocity Field

R. Giovanelli·M. Haynes·J. Salzer·G. Wegner·L. da Costa·W. Freudling
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Abstract

In preceding papers of this series, TF relations for galaxies in 24 clusters with radial velocities between 1000 and 9200 km/s (SCI sample) were obtained, a Tully-Fisher (TF) template relation was constructed and mean offsets of each cluster with respect to the template obtained. Here, an estimate of the line-of-sight peculiar velocities of the clusters and their associated errors are given. It is found that cluster peculiar velocities in the Cosmic Microwave Background reference frame do not exceed 600 k/ms and that their distribution has a line-of-sight dispersion of 300 k/ms, suggesting a more quiescent cluster peculiar velocity field than previously reported. When measured in a reference frame in which the Local Group is at rest, the set of clusters at cz > 3000 km/s exhibits a dipole moment in agreement with that of the CMB, both in amplitude and apex direction. It is estimated that the bulk flow of a sphere of 6000 km/s radius in the CMB reference frame is between 140 and 320 km/s. These results are in agreement with those obtained from an independent sample of field galaxies (Giovanelli et al. 1998; see astro-ph/9807274)

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R. Giovanelli, M. Haynes, J. Salzer, G. Wegner, L. da Costa, W. Freudling. 1998-08-14. The Motions of Clusters of Galaxies and the Dipoles of the Peculiar Velocity Field. https://doi.org/10.1086/300652

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