Non-linear gravitational clustering of cold matter in an expanding universe: indications from 1D toy models

Abstract

Studies of a class of infinite one dimensional self-gravitating systems have highlighted that, on the one hand, the spatial clustering which develops may have scale invariant (fractal) properties, and, on the other, that they display "self-similar" properties in their temporal evolution. The relevance of these results to three dimensional cosmological simulations has remained unclear. We show here that the measured exponents characterizing the scale-invariant non-linear clustering are in excellent agreement with those derived from an appropriately generalized "stable-clustering" hypothesis. Further an analysis in terms of "halos" selected with a friend-of-friend algorithm reveals that such structures are, statistically, virialized across the range of scales corresponding to scale-invariance. Thus the strongly non-linear clustering in these models is accurately described as a virialized fractal structure, very much in line with the "clustering hierarchy" which Peebles originally envisaged qualitatively as associated with stable clustering. If transposed to three dimensions these results would imply, notably, that cold dark matter halos (or even subhalos) are 1) not well modeled as smooth objects, and 2) that the supposed "universality" of their profiles is, like apparent smoothness, an artefact of poor numerical resolution.

9 pages, 4 figures (one in color), additional references and short discussion on collisionality, version to appear in MNRAS

References in corpus (9)

• The survival and disruption of CDM micro-haloes: implications for direct and indirect detection experiments
• The Graininess of Dark Matter Haloes
• Discreteness Effects in Lambda Cold Dark Matter Simulations: A Wavelet-Statistical View
• Towards quantitative control on discreteness error in the non-linear regime of cosmological N body simulations
• Dark Matter Halo Profiles in Scale-Free Cosmologies
• Relaxation of a 1-D gravitational system
• Halos and voids in a multifractal model of cosmic structure
• Gravitational Dynamics of an Infinite Shuffled Lattice of Particles
• Gravitational dynamics of an infinite shuffled lattice: early time evolution and universality of non-linear correlations

Cited by in corpus (14)

• Nonequilibrium Statistical Mechanics of Systems with Long-Range Interactions: Ubiquity of Core-Halo Distributions
• Cosmological structure formation with negative mass
• Post-collapse perturbation theory in 1D cosmology -- beyond shell-crossing
• Gravitational Collapse in One Dimension
• The Fractal Geometry of the Cosmic Web and its Formation
• Exponents of non-linear clustering in scale-free one dimensional cosmological simulations
• Scaling quasi-stationary states in long range systems with dissipation
• Attractor non-equilibrium stationary states in perturbed long-range interacting systems
• Structure formation in a Dirac-Milne universe: comparison with the standard cosmological model
• Cosmology in One Dimension: Vlasov Dynamics
• Stable clustering and the resolution of dissipationless cosmological N-body simulations
• Power spectrum response of large-scale structure in 1D and in 3D: tests of prescriptions for post-collapse dynamics
• Kinetic properties of fractal media
• Halo Models of Large Scale Structure and Reliability of Cosmological N-Body Simulations