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Session 116 - Large Scale Structure.
Oral session, Thursday, January 16
Piers 4/5,

[116.03] The Peculiar Velocity Function of Galaxy Clusters

N. A. Bahcall, S. P. Oh (Princeton U.)

The peculiar velocity function of clusters of galaxies is determined using an accurate sample of cluster velocities based on Tully-Fisher distances of Sc galaxies (Giovanelli et al). In contrast to previous results based on samples with considerably larger velocity uncertainties, the observed velocity function does not exhibit a tail of high peculiar velocity clusters. The results indicate a low probablity of < 5one-dimensional peculiar velocities greater than 600 km/s. The rms one-dimensional cluster peculiar velocity is 293 +- 28 km/s. The observed cluster velocity function is compared with expectations from different cosmological models. The absence of a high velocity tail in the observed function is most consistent with a low mass-density (omega 0.3) CDM model and is inconsistent at the >3sigma level with omega=1 CDM and HDM models.

Program listing for Thursday