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The Press-Schechter theory of the cosmological mass function and its modifications allow to constraint cosmological scenarios of the structure formation. Recently a few new models have been suggested that explored the influence of…

Astrophysics · Physics 2015-06-24 Sergei F. Shandarin

We study the dynamical evolution of idealised stellar systems by averaging results from many $N$-body simulations, each having modest numbers of stars. For isolated systems with stars of uniform mass, we discuss aspects of evolution up to…

Astrophysics · Physics 2015-06-24 Mirek Giersz , Douglas C. Heggie

We address the dynamical evolution of an isolated self--gravitating system with two stellar mass groups. We vary the individual ratio of the heavy to light bodies, $\mu$ from 1.25 to 50 and alter also the fraction of the total heavy mass…

Astrophysics · Physics 2008-11-26 Emil Khalisi , Pau Amaro-Seoane , Rainer Spurzem

We use cosmological simulations to explore the large-scale effects of reionization. Since reionization is a process that involves a large dynamic range - from galaxies to rare bright quasars - we need to be able to cover a significant…

Astrophysics · Physics 2008-11-26 Katharina Kohler , Nickolay Y. Gnedin , Andrew J. S. Hamilton

N-body simulations and analytical calculations of the gravitational collapse in an expanding universe predict that halos should form with a diverging inner density profile, the cusp. There are some observational indications that the dark…

Astrophysics · Physics 2009-11-06 Amr El-Zant , Isaac Shlosman , Yehuda Hoffman

The `core-cusp' problem is considered a key challenge to the LCDM paradigm. Halos in dark matter only simulations exhibit `cuspy' profiles, where density continuously increases towards the centre. However, the dark matter profiles of many…

Astrophysics of Galaxies · Physics 2024-01-09 R. A. Jackson , S. Kaviraj , S. K. Yi , S. Peirani , Y. Dubois , G. Martin , J. E. G. Devriendt , A. Slyz , C. Pichon , M. Volonteri , T. Kimm , K. Kraljic

We present the problematic of controlling the discreteness effects in cosmological N-body simulations. We describe a perturbative treatment which gives an approximation describing the evolution under self-gravity of a lattice perturbed from…

Statistical Mechanics · Physics 2009-11-13 B. Marcos

Adaptive SPH and N-body simulations were carried out to study the effect of gasdynamics on the structure of dark matter halos that result from the gravitational instability and fragmentation of cosmological pancakes. Such halos resemble…

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

Newtonian N-body simulations have been employed successfully over the past decades for the simulation of the cosmological large-scale structure. Such simulations usually ignore radiation perturbations (photons and massless neutrinos) and…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-07 Julian Adamek , Jacob Brandbyge , Christian Fidler , Steen Hannestad , Cornelius Rampf , Thomas Tram

Self-Interacting Dark Matter (SIDM) is a collisional form of cold dark matter (CDM), originally proposed to solve problems that arose when the collisionless CDM theory of structure formation was compared with observations of galaxies on…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Jun Koda , Paul R. Shapiro

We discuss the role that numerical effects have in cosmological N-Body/SPH simulations of disk galaxy formation. We show that the resolution of current state-of-the-art calculations, about $10^5$ SPH and dark matter particles within the…

Astrophysics · Physics 2007-05-23 Lucio Mayer

We apply and test a field-level emulator for non-linear cosmic structure formation in a volume matching next-generation surveys. Inferring the cosmological parameters and initial conditions from which the particular galaxy distribution of…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-20 Matthew T. Scoggins , Matthew Ho , Francisco Villaescusa-Navarro , Drew Jamieson , Ludvig Doeser , Greg L. Bryan

Using state-of-the-art adaptive mesh refinement cosmological hydrodynamic simulations with a spatial resolution of proper 0.21kpc/h in refined subregions embedded within a comoving cosmological volume (27.4Mpc/h)^3, we investigate the sizes…

Astrophysics · Physics 2009-11-13 M. K. Ryan Joung , Renyue Cen , Greg Bryan

We investigate the core-cusp problem of the $\Lambda$ cold dark matter ($\Lambda$CDM) scenario in the context of Modified Newtonian Dynamics (MOND) paradigm exploiting the concept of equivalent Newtonian system (ENS). By means of…

Astrophysics of Galaxies · Physics 2023-10-18 Federico Re , Pierfrancesco Di Cintio

The relation between the results of cosmological N-body simulations, and the continuum theoretical models they simulate, is currently not understood in a way which allows a quantification of N dependent effects. In this first of a series of…

Astrophysics · Physics 2013-05-29 Michael Joyce , Bruno Marcos

The small-scale power spectrum of the cosmological matter distribution together with other cosmological data provides a sensitive measure of the hot dark matter fraction, leading to restrictive neutrino mass limits. We extend this argument…

High Energy Physics - Phenomenology · Physics 2009-11-10 Steen Hannestad , Georg Raffelt

Cosmological N-body simulations are done on massively parallel computers. This necessitates the use of simple time integrators, and, additionally, of mesh-grid approximations of the potentials. Recently, Adamek et al. (2015);…

Numerical Analysis · Mathematics 2023-05-23 Jean-Pierre Eckmann , Farbod Hassani

The diversity of galaxy morphologies and their relations with galaxy and halo properties is fundamental to understanding galaxy formation. Cosmological simulations of representative volumes can help disentangle the origin of observed…

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

Astrophysics · Physics 2009-11-06 Marcelo Alvarez , Paul R. Shapiro , Hugo Martel

Wang and White (2007) have discussed some problems with N-body simulation methods. These problems are a special case of a more general problem which has been largely unacknowledged for approximately 25 years, and affects results of all dark…

Astrophysics · Physics 2007-09-07 Adrian L. Melott