A new test for the stable clustering hypothesis

Abstract

The stable clustering hypothesis is a fundamental assumption about the nonlinear clustering of matter in cosmology. It states that the mean physical separation of particles is a constant on sufficiently small scales. While many authors have attempted to test the hypothesis with cosmological N-body simulations, no consensus has been reached on whether and where the hypothesis is valid, because of the limited dynamical range this type of simulations can achieve. In this Letter, we propose to test the hypothesis with high resolution halo simulations, since the individual halo simulations can resolve much better the fine structures of the halos and since almost all pairs of particles with small separations are presumed to be inside virialized halos. We calculated the mean pair velocity for 14 high resolution halos of $\sim 1$ million particles in a low-density flat cold dark matter model. The result agrees very well with the stable clustering prediction within the measurement uncertainty $\sim 30$ over a large range of scales where the overdensity is $10^3$ to $10^6$. The accuracy of the test can be improved to $\sim 10$ if some 100 halos with a similar resolution are analyzed.

accepted for publication in ApJ; minor changes; 10 pages with 3 figures included

References in corpus (8)

• Mass function of dark matter halos
• Analytic model for galaxy and dark matter clustering
• Halo occupation numbers and galaxy bias
• How Many Galaxies Fit in a Halo? Constraints on Galaxy Formation Efficiency from Spatial Clustering
• Deriving the Nonlinear Cosmological Power Spectrum and Bispectrum from Analytic Dark Matter Halo Profiles and Mass Functions
• Weak Lensing by Large-Scale Structure: A Dark Matter Halo Approach
• Halo Profiles and the Nonlinear Two- and Three-Point Correlation Functions of Cosmological Mass Density
• What Does It Take to Stabilize Gravitational Clustering?

Cited by in corpus (8)

• Clustering in the Phase Space of Dark Matter Haloes. II. Stable Clustering and Dark Matter Annihilation
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• The background Friedmannian Hubble constant in relativistic inhomogeneous cosmology and the age of the Universe
• Mean-pairwise peculiar velocity in cosmological N-body simulations: time-variation, scale-dependence and stable condition
• Cosmology in One Dimension: The Two Component Universe
• Gravitational Collapse in an Expanding Universe: Scaling Relations for Two-Dimensional Collapse Revisited
• Quasi-self-similar evolution of the two-point correlation function: strongly nonlinear regime in Omega_0 < 1 universes
• Energy Ranking Preservation in a N-Body Cosmological Simulation