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The mean matter density within the turnaround radius, which is the boundary that separates a nonexpanding structure from the Hubble flow, was recently proposed as a novel cosmological probe. According to the spherical collapse model, the…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-14 Giorgos Korkidis , Vasiliki Pavlidou , Konstantinos Tassis

We describe cosmological simulation techniques and their application to studies of cosmic structure formation, with particular attention to recent hydrodynamic simulations of structure in the high redshift universe. Collisionless N-body…

Astrophysics · Physics 2008-02-03 David H. Weinberg , Neal Katz , Lars Hernquist

We present two matched sets of five simulations each, covering five presently favored simple modifications to the standard cold dark matter (CDM) scenario. One simulation suite, with a linear box size of 75 Mpc/h, is designed for high…

Considering perturbation growth in spherical Top-Hat model of structure formation in a generalized Chaplygin gas dominated universe, we want to study this scenario with a modified Chaplygin gas model. The evolution of background and…

General Relativity and Quantum Cosmology · Physics 2015-05-11 S. Karbasi , H. Razmi

We present results of cosmological N-body hydrodynamic chemistry simulations of primordial structure growth and evolution in a scenario with warm dark matter (WDM) having a mass of 3 keV (thermal relic) and compare with a model consisting…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Umberto Maio , Matteo Viel

In this work we investigate the spherical collapse model in flat FRW dark energy universes. We consider the Holographic Dark Energy (HDE) model as a dynamical dark energy scenario with a slowly time-varying equation-of-state (EoS) parameter…

General Relativity and Quantum Cosmology · Physics 2015-01-27 Tayebe Naderi , Mohammad Malekjani , Francesco Pace

We investigate the coupled formation and evolution of galaxies and their embedded supermassive black holes using state-of-the-art hydrodynamic simulations of cosmological structure formation. For the first time, we self-consistently follow…

Astrophysics · Physics 2009-11-13 Tiziana Di Matteo , Joerg Colberg , Volker Springel , Lars Hernquist , Debora Sijacki

The simulated matter distribution on large scales is studied using core-sampling, cluster analysis, inertia tensor analysis, and minimal spanning tree techniques. Seven simulations in large boxes for five cosmological models with COBE…

Astrophysics · Physics 2011-07-19 A. G. Doroshkevich , V. Müller , J. Retzlaff , V. Turchaninov

Topological defects are ubiquitous in physics. Whenever a symmetry breaking phase transition occurs, topological defects may form. The best known examples are vortex lines in type II super conductors or in liquid Helium, and declination…

Astrophysics · Physics 2011-07-19 R. Durrer , M. Kunz , A. Melchiorri

We study first structure formation in Lambda-dominated universes using large cosmological N-body/SPH simulations. We consider a standard LCDM model and a LWDM model in which the mass of the dark matter particles is taken to be m_X=10 keV.…

Astrophysics · Physics 2011-07-19 Naoki Yoshida , Aaron Sokasian , Lars Hernquist , Volker Springel

We investigate a cosmological scenario in which the dark matter particles can be created during the evolution of the Universe. By regarding the Universe as an open thermodynamic system and using non-equilibrium thermodynamics, we examine…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-20 Z. Safari , K. Rezazadeh , B. Malekolkalami

We intend to understand cosmological structure formation within the framework of superfluid models of dark matter with finite temperatures. Of particular interest is the evolution of small-scale structures where the pressure and superfluid…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-28 S. T. H. Hartman , H. A. Winther , D. F. Mota

The standard cold dark matter (CDM) model predicts too many and too dense small structures. We consider an alternative model that the dark matter undergoes two-body decays with cosmological lifetime $\tau$ into only one type of massive…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-04 Dalong Cheng , M. -C. Chu , Jiayu Tang

We study the non-linear structure formation in cosmology accounting for the quantum nature of the dark matter (DM) particles in the initial conditions at decoupling, as well as in the relaxation and stability of the DM halos. Differently…

Astrophysics of Galaxies · Physics 2022-03-14 Carlos R. Argüelles , Eduar A. Becerra-Vergara , Andreas Krut , Rafael Yunis , Jorge A. Rueda , Remo Ruffini

We present a kinetic theory for the evolution of the phase-space distribution of dark matter particles in galaxy halos in the presence of a cosmological spectrum of fluctuations. This theory introduces a new way to model the formation and…

Astrophysics · Physics 2009-11-10 Chung-Pei Ma , Edmund Bertschinger

We study the evolution of inhomogeneous spherical perturbations in the universe in a way that generalizes the spherical top hat collapse in a straightforward manner. For that purpose we derive a dynamical equation for the evolution of the…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-13 T. S. Pereira , R. Rosenfeld , A. Sanoja

We introduce a novel approach, the Cosmological Trajectories Method (CTM), to model nonlinear structure formation in the Universe by expanding gravitationally-induced particle trajectories around the Zel'dovich approximation. A new Beyond…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-04 F. C. Lane , A. N. Taylor , D. Sorini

The set-up of the initial conditions in cosmological N-body simulations is usually implemented by rescaling the desired low-redshift linear power spectrum to the required starting redshift consistently with the Newtonian evolution of the…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-18 Matteo Zennaro , Julien Bel , Francisco Villaescusa-Navarro , Carmelita Carbone , Emiliano Sefusatti , Luigi Guzzo

In the standard picture of cosmological structure formation, the Universe we see today is evolved under the gravitational instability from tiny random fluctuations. In this talk I discuss the onset of non-linearity in the large scale…

Astrophysics · Physics 2007-05-23 Lung-Yih Chiang

We carry out fully 3-dimensional simulations of evolution from self-similar, spherically symmetric linear perturbations of a Cold Dark Matter dominated Einstein-de Sitter universe. As a result of the radial orbit instability, the haloes…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Mark Vogelsberger , Roya Mohayaee , Simon D. M. White