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Adaptive SPH and N-body simulations were carried out to study the collapse and evolution of dark matter halos that result from the gravitational instability and fragmentation of cosmological pancakes. Such halos resemble those formed by…

Astrophysics · Physics 2007-05-23 Marcelo A. Alvarez , Paul R. Shapiro , Hugo Martel

(Context) In a Universe dominated by dark matter, halos are continuously accreting mass (violently or not) and such mechanism affects their dynamical state. (Aims) The evolution of dark matter halos in phase-space, and using the phase-space…

Astrophysics · Physics 2009-05-03 S. Peirani , J. A. de Freitas Pacheco

Navarro, Frenk, and White have suggested that the density profiles of simulated dark matter halos have a ``universal'' shape so that a given halo can be characterized by a single free parameter which fixes its mass. In this paper, we…

Astrophysics · Physics 2009-10-30 Richard N. Henriksen , Lawrence M. Widrow

The evolution of the virial overdensity $\Delta_{\rm vir}$ for $\Lambda$CDM and seven dynamical dark-energy models is investigated in the extended spherical collapse model (SCM). Here the virialization process is naturally achieved by…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-10 Francesco Pace , Carlo Schimd , David F. Mota , Antonino Del Popolo

It is common practice to describe formal size and mass scales of dark matter halos as spherical overdensities with respect to an evolving density threshold. Here, we critically investigate the evolutionary effects of several such commonly…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Marcel Zemp

In excursion set theory the computation of the halo mass function is mapped into a first-passage time process in the presence of a barrier, which in the spherical collapse model is a constant and in the ellipsoidal collapse model is a fixed…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-18 Michele Maggiore , Antonio Riotto

We develop a spherical self-similar model for the formation of a galaxy through gas collapsing in an isolated self-gravitating dark matter halo. We improve upon the existing literature on self-similar collapse in two ways. First, we include…

Astrophysics of Galaxies · Physics 2024-04-05 Premvijay Velmani , Aseem Paranjape

In the framework of the spherical collapse model we study the influence of shear and rotation terms for dark matter fluid in clustering dark energy models. We evaluate, for different equations of state, the effects of these terms on the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 F. Pace , R. C. Batista , A. Del Popolo

We review the physics of halo collapse giving rise to various halo boundaries, as well as their identification, observation, and applications. The classical halo is typically defined as a monolithic, virialized object enclosed within its…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-04 Jiaxin Han

We combine the physics of the ellipsoidal collapse model with the excursion set theory to study the shapes of dark matter halos. In particular, we develop an analytic approximation to the nonlinear evolution that is more accurate than the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Graziano Rossi , Ravi K. Sheth , Giuseppe Tormen

The radial mass distribution of dark matter haloes is investigated within the framework of the spherical infall model. We present a new formulation of spherical collapse including non-radial motions, and compare the analytical profiles with…

Astrophysics · Physics 2009-11-10 Y. Ascasibar , G. Yepes , S. Gottloeber , V. Mueller

We revisit the non-sphericity of cluster-mass scale halos from cosmological N-body simulation on the basis of triaxial modelling. In order to understand the difference between the simulation results and the conventional ellipsoidal collapse…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-12 Daichi Suto , Tetsu Kitayama , Takahiro Nishimichi , Shin Sasaki , Yasushi Suto

We study gravothermal evolution of dark matter halos in the presence of differential self-scattering that has strong velocity and angular dependencies. We design controlled N-body simulations to model Rutherford and Moller scatterings in…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-05 Daneng Yang , Hai-Bo Yu

I examine differences in non-linear structure formation between cosmological models that share a $z=0$ linear power spectrum in both shape and amplitude, but that differ via their growth history. $N$-body simulations of these models display…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-15 Alexander Mead

In hierarchical models, the time derivative of the halo mass function may be thought of as the difference of two terms - a creation term, which describes the increase in the number of haloes of mass m from mergers of less massive objects,…

Astrophysics · Physics 2009-07-10 Jorge Moreno , Carlo Giocoli , Ravi K. Sheth

We study the spherical collapse model in the presence of external gravitational tidal shear fields for different dark energy scenarios and investigate the impact on the mass function and cluster number counts. While previous studies of the…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-12 Robert Reischke , Francesco Pace , Sven Meyer , Björn Malte Schäfer

The abundance of massive dark matter halos hosting galaxy clusters provides an important test of the masses of relic neutrino species. The dominant effect of neutrino mass is to lower the typical amplitude of density perturbations that…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-03 Marilena LoVerde

We investigate the structure of cold dark matter halos using advanced models of spherical collapse and accretion in an expanding Universe. These base on solving time-dependent equations for the moments of the phase-space distribution…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 A. Lapi , A. Cavaliere

The top-hat spherical collapse model (TSC) is one of the most fundamental analytical frameworks to describe the non-linear growth of cosmic structure. TSC has motivated, and been widely applied in, various researches even in the current era…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-20 Daichi Suto , Tetsu Kitayama , Ken Osato , Shin Sasaki , Yasushi Suto

Traditionally the spherical collapse of objects is studied with respect to a uniform background density, yielding the critical over-density $\delta_\mathrm{c}$ as key ingredient to the mass function of virialized objects. Here we…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-26 Robert Reischke , Francesco Pace , Sven Meyer , Björn Malte Schäfer
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