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Velocity correlations of galaxy clustersWe determine the velocity correlation function, pairwise peculiar velocity difference, and rms pairwise peculiar velocity dispersion of rich clusters of galaxies, as a function of pair separation, for three cosmological models: Omega = 1 and Omega = 0.3 cold dark matter (CDM), and Omega = 0.3 primeval baryonic isocurvature (PBI) models (all flat and Cosmic Background Explorer (COBE)-normalized). We find that close cluster pairs, with separation r is less than or equal to 10/h Mpc, exhibit strong attractive peculiar velocities in all models; the cluster pairwise velocities depend sensitively on the model. The mean pairwise attractive velocity of clusters on 5/h Mpc scale ranges from approximately 1700 km/s for Omega = 1 CDM to approximately 1000 km/s for PBI to approximately 700 km/s for Omega = 0.3 CDM. The small-scale pairwise velocities depend also on cluster mass: richer, more massive clusters exhibit stronger attractive velocities than less massive clusters. On large scales, from approximately 20 to 200/h Mpc, the cluster peculiar velocities are increasingly dominated by bulk and random motions; they are independent of cluster mass. The cluster velocity correlation function is negative on small scales for Omega = 1 and Omega = 0.3 CDM, indicating strong pairwise motion relative to bulk motion on small scales; PBI exhibits relatively larger bulk motions. The cluster velocity correlation function is positive on very large scales, from r approximately 10/h Mpc to r approximately 200/h Mpc, for all models. These positive correlations, which decrease monotonically with scale, indicate significant bulk motions of clusters up to approximately 200/h Mpc. The strong dependence of the cluster velocity functions on models, especially at small separations, makes them useful tools in constraining cosmological models when compared with observations.
Document ID
19950040646
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Cen, Renyue
(Princeton University Observatory, Princeton, NJ, United States)
Bahcall, Neta A.
(Princeton University Observatory, Princeton, NJ, United States)
Gramann, Mirt
(Princeton University Observatory, Princeton, NJ, United States)
Date Acquired
August 16, 2013
Publication Date
December 10, 1994
Publication Information
Publication: Astrophysical Journal, Part 2 - Letters
Volume: 437
Issue: 1
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
95A72245
Funding Number(s)
CONTRACT_GRANT: NAGW-2448
CONTRACT_GRANT: NSF AST-93-15368
CONTRACT_GRANT: NSF ASC-93-18185
CONTRACT_GRANT: NSF AST-90-20506
CONTRACT_GRANT: NSF AST-91-08103
Distribution Limits
Public
Copyright
Other

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