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We study the biasing relation between dark-matter halos or galaxies and the underlying mass distribution, using cosmological $N$-body simulations in which galaxies are modelled via semi-analytic recipes. The nonlinear, stochastic biasing is…

天体物理学 · 物理学 2009-09-25 R. S. Somerville , G. Lemson , Y. Sigad , A. Dekel , G. Kauffmann , S. D. M. White

Cosmological N--body simulations have revealed a remarkable similarity in the structure of dark matter halos formed in hierarchically clustering universes. Regardless of halo mass, cosmological parameters, and power spectrum of initial…

天体物理学 · 物理学 2007-05-23 Julio F. Navarro

For the spherical symmetric case, all quantities describing the relaxed dark matter halo can be expressed as functions of the gravitational potential $\Phi$. Decomposing the radial velocity dispersion $\sigma_r$ with respect to $\Phi$ at…

天体物理学 · 物理学 2009-11-07 J. P. Muecket , M. Hoeft

Astronomical observations strongly suggest that our universe is now accelerating and contains a substantial admixture of dark vacuum energy. Using numerical simulations to study this newly consolidated cosmological model (with a constant…

天体物理学 · 物理学 2009-11-10 Fred C. Adams , Michael T. Busha , August E. Evrard , Risa H. Wechsler

High-resolution cosmological N-body simulations were performed in order to study the substructure of Milky Way-like galactic halos and the density profiles of halos in a warm dark matter scenario. The results favor this scenario with…

天体物理学 · 物理学 2007-05-23 P. Colin , V. Avila-Reese , O. Valenzuela

The structure of astrophysical objects is usually modeled under the assumption of hydrostatic equilibrium. However, actual configurations may deviate from perfect spherical or isotropic properties. Consequently, cosmic objects are expected…

广义相对论与量子宇宙学 · 物理学 2025-06-11 Hermano Velten , Felipe S. Escórcio , Nadson J. S. Trindade

Non-equilibrium systems have long-ranged spatial correlations even far away from critical points. This implies that the likelihoods of spatial steady state profiles of physical observables are nonlocal functionals. In this letter, it is…

统计力学 · 物理学 2015-05-14 Otto Pulkkinen

The shapes of individual self-gravitating structures of an ensemble of identical, collisionless particles have remained elusive for decades. In particular, a reason why mass density profiles like the Navarro-Frenk-White or the Einasto…

宇宙学与河外天体物理 · 物理学 2020-07-01 Jenny Wagner

The density profiles and other quantities of physical interest for spherically symmetric systems are computed by assuming that a collisionless stellar gas may relax to the non-Gaussian power law distribution suggested by the nonextensive…

天体物理学 · 物理学 2011-07-19 J. A. S. Lima , R. E. de Souza

Our previous works have shown the statistical mechanics of self-gravitating system. In this paper, we will show its thermodynamics and compare our results with observations and simulations. We propose that our statistical mechanics can be…

宇宙学与河外天体物理 · 物理学 2011-12-30 Dong-Biao Kang

In a previous study, we formulated a framework of the entropy-based equilibrium statistical mechanics for self-gravitating systems. This theory is based on the Boltzmann-Gibbs entropy and includes the generalized virial equations as…

宇宙学与河外天体物理 · 物理学 2012-04-10 Ping He

The late stages of large-scale structure evolution are treated semi-analytically within the framework of modified halo model. We suggest simple yet accurate approximation for relating the non-linear amplitude to linear one for spherical…

宇宙学与河外天体物理 · 物理学 2013-12-10 Yurij Kulinich , Bohdan Novosyadlyj , Stepan Apunevych

Working within the deep-MOND limit (DML), I describe spherical, self-gravitating systems governed by a polytropic equation of state, $P=\mathcal{K}\rho^\gamma$. As self-consistent structures, such systems can serve as heuristic models for…

星系天体物理 · 物理学 2021-03-03 Mordehai Milgrom

We present a method for populating dark matter simulations with haloes of mass below the resolution limit. It is based on stochastically sampling a field derived from the density field of the halo catalogue, using constraints from the…

宇宙学与河外天体物理 · 物理学 2015-06-12 Sylvain de la Torre , John A. Peacock

We present a new approach to measure the mass function of dark matter halos and to discriminate models with differing values of Omega through weak gravitational lensing. We measure the distribution of peaks from simulated lensing surveys…

天体物理学 · 物理学 2009-10-31 Bhuvnesh Jain , Ludovic Van Waerbeke

Dark matter simulations require statistical techniques to properly identify and classify their halos and structures. Nonparametric solutions provide catalogs of these structures but lack the additional learning of a model-based algorithm…

星系天体物理 · 物理学 2022-11-09 Lluís Hurtado-Gil , Michael A. Kuhn , Pablo Arnalte-Mur , Eric D. Feigelson , Vicent Martínez

We study the structure and substructure of halos obtained in N-body simulations for a Lambda Cold Dark Matter (LCDM) cosmology with non-Gaussian initial conditions (NGICs). The initial statistics are lognormal in the gravitational potential…

天体物理学 · 物理学 2008-11-26 V. Avila-Reese , P. Colin , G. Piccinelli , C. Firmani

The statistical mechanics of N cold dark matter (CDM) particles interacting via a softened gravitational potential is reviewed in the microcanonical ensemble and mean-field limit. A phase diagram for the system is computed as a function of…

天体物理学 · 物理学 2014-10-13 Cathryn M. Trott , Andrew Melatos

Cosmological N-body simulations have been a major tool of theorists for decades, yet many of the numerical issues that these simulations face are still unexplored. This paper measures numerical biases in these large, dark matter-only…

宇宙学与河外天体物理 · 物理学 2020-11-11 Philip Mansfield , Camille Avestruz

We demonstrate the equilibration of isolated macroscopic quantum systems, prepared in non-equilibrium mixed states with significant population of many energy levels, and observed by instruments with a reasonably bound working range compared…

统计力学 · 物理学 2009-11-13 Peter Reimann