On the Universality of the Bound-Zone Peculiar Velocity Profile

Abstract

A numerical evidence for the universality of the bound-zone peculiar velocity profile in a LambdaCDM universe is presented. Analyzing the dark matter halo catalogs from the Millennium-II simulation, we determine the average peculiar velocity profiles of the objects located in the bound zones around massive group-size halos at various redshifts and compare them to an analytic formula characterized by two parameters, the amplitude and slope of the profile. The best-fit values of the two parameters are found to be robust against the changes of the mass scales and the key cosmological parameters. It is also found that the amplitude and slope parameters of the bound-zone peculiar velocity profile are constant but only in the limited ranges of redshifts. In the dark matter dominated epoch corresponding to z> 0.6 the two parameters have constant values. In the transition period corresponding to 0.2=< z=< 0.6 when the density of Lambda begins to exceed that of dark matter the two parameters grow almost linearly with redshifts. At later epochs z<0.2 when the Lambda-domination prevails the two parameters regain constancy settling upon higher constant values. Noting that the length of the transition period depends on the amount of Lambda and speculating that the linear evolution of the profile with redshifts in the transition period is a unique feature of the Lambda-dominated universe, we suggest that the redshift evolution of the bound-zone peculiar velocity profile should be a powerful local discriminator of dark energy candidates.

accepted for publication in ApJ, a mistake in the calculation of the bound-zone peculiar velocity profile corrected

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Cited by in corpus (13)

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• Estimating the Turn-Around Radii of Six Isolated Galaxy Groups in the Local Universe
• Distinguishing cosmologies using the turn-around radius near galaxy clusters
• Constraining phantom braneworld model from cosmic structure sizes
• Turnaround size of non-spherical structures
• Turnaround physics beyond spherical symmetry
• The maximum turnaround radius for axisymmetric cosmic structures
• Turnaround radius in scalar-tensor gravity with quasilocal mass
• Independent Measurements of the Dynamical Masses of Six Galaxy Clusters in the Local Universe
• Searching for a signature of turnaround in galaxy clusters with convolutional neural networks