http://arxiv.org/abs/1603.06672
We present a numerical evidence that the amplitude and slope of the bound-zone peculiar velocity profile grow at the constant rates in a LambdaCDM universe. Analyzing the friends-of-friends halo catalogs from the Millennium-II simulations at various redshifts, we measure the average peculiar velocity profile of the objects located in the bound zone around massive group-size halos and compare it to an analytic formula characterized by the amplitude and slope parameters. It is shown that the amplitude and slope of the bound-zone peculiar velocity profile remain constant in the dark matter dominated epoch but begin to grow linearly with redshift after the onset of the Lambda-domination. Our explanation for this phenomenon is that as the balance between the gravitational attraction of the massive groups and the repulsive force of the Hubble expansion cracks up in the Lambda-dominated epoch, the gravitational influence on the bound-zone halos diminishes more rapidly with the increment of the radial distances. Speculating that the constant growth rate of the amplitude and slope of the bound-zone peculiar velocity profile is a unique feature of a Lambda-dominated universe, we suggest that the redshift evolution of the amplitude and slope of the bound-zone peculiar velocity profile should be a powerful local discriminator of dark energy candidates.
J. Lee
Wed, 23 Mar 16
57/73
Comments: submitted for publication in ApJ, 10 figures, 2 tables
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