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We study the response of star clusters to individual tidal perturbations using controlled $N$-body simulations. We consider perturbations by a moving point mass and by a disc, and vary the duration of the perturbation as well as the cluster…

Astrophysics of Galaxies · Physics 2022-08-12 Luis A. Martinez-Medina , Mark Gieles , Oleg Y. Gnedin , Hui Li

Using numerical hydrodynamics simulations we studied the gravitational collapse of pre-stellar cores of sub-solar mass embedded into a low-density external environment. Four models with different magnitude and direction of rotation of the…

Solar and Stellar Astrophysics · Physics 2015-06-23 Eduard I. Vorobyov , D. N. C. Lin , Manuel Guedel

The origin of the observed morphological and kinematic substructure of young star forming regions is a matter of debate. We offer a new analysis of data from simulations of globally gravitationally collapsing clouds of progenitor gas to…

Astrophysics of Galaxies · Physics 2017-11-15 Aleksandra Kuznetsova , Lee Hartmann , Javier Ballesteros-Paredes

We explore semiclassical stellar collapse scenarios with pressure within the framework of effective loop quantum gravity. The objective of this work is to generalize existent models of semiclassical dust collapse and examine the role of…

General Relativity and Quantum Cosmology · Physics 2025-09-30 Luca Cafaro , Lorenzo Cipriani , Francesco Fazzini , Farshid Soltani

With the goal to refine modelling of shell galaxies and the use of shells to probe the merger history, we develop a new method for implementing dynamical friction in test-particle simulations of radial minor mergers. The friction is…

Astrophysics of Galaxies · Physics 2011-03-23 Ivana Ebrova , Bruno Jungwiert , Gabriela Canalizo , Nicola Bennert , Lucie Jilkova

We use the FLAMINGO galaxy formation model to quantify the impact of baryon-CDM isocurvature perturbations on galaxy formation in $\Lambda$CDM. In linear theory, these perturbations represent local, compensated variations in the ratio…

Astrophysics of Galaxies · Physics 2026-05-04 Owen Jessop , Adrian Jenkins , Andrew Pontzen , Joop Schaye , Matthieu Schaller , John C. Helly

The halo mass function from N-body simulations of collisionless matter is generally used to retrieve cosmological parameters from observed counts of galaxy clusters. This neglects the observational fact that the baryonic mass fraction in…

Cosmology and Nongalactic Astrophysics · Physics 2013-04-16 A. Balaguera-Antolinez , Cristiano Porciani

We investigate the collapse of non-spherical substructures, such as sheets and filaments, which are ubiquitous in molecular clouds. Such non-spherical substructures collapse homologously in their interiors but are influenced by an edge…

Astrophysics of Galaxies · Physics 2012-08-27 Andy Pon , Jesús A. Toalá , Doug Johnstone , Enrique Vázquez-Semadeni , Fabian Heitsch , Gilberto C. Gómez

Core collapse is a prominent evolutionary stage of self-gravitating systems. In an idealised collisionless approximation, the region around the cluster core evolves in a self-similar way prior to the core collapse. Thus, its radial density…

Astrophysics of Galaxies · Physics 2018-12-05 Václav Pavlík , Ladislav Šubr

We model in simple terms the angular-momentum problems of galaxy formation in CDM cosmologies, and identify the key elements of a scenario that may solve them. The buildup of angular momentum is modeled via dynamical friction and tidal…

Astrophysics · Physics 2008-11-26 Ariyeh H. Maller , Avishai Dekel

Dark energy has a dramatic effect on the dynamics of the universe, causing the recently discovered acceleration of the expansion. The dynamics are also central to the behavior of the growth of large scale structure, offering the possibility…

Astrophysics · Physics 2009-11-07 Eric V. Linder , Adrian Jenkins

The analytical generalization of the classical dynamical friction formula (derived under the assumption that all the field particles have the same mass) to the case in which the masses of the field particles are distributed with a mass…

Astrophysics of Galaxies · Physics 2015-05-18 Luca Ciotti

We investigate numerically and semi-analytically the collapse of low-mass, rotating prestellar cores. Initially, the cores are in approximate equilibrium with low rotation (the initial ratio of thermal to gravitational energy is $\alpha_0…

Astrophysics · Physics 2009-11-10 P. Hennebelle , A. Whitworth , S. Cha , S. Goodwin

We investigate the gravitational fragmentation of expanding shells in the context of the linear thin--shell analysis. We make use of two very different numerical schemes; the FLASH Adaptive Mesh Refinement code and a version of the Benz…

Astrophysics of Galaxies · Physics 2015-05-13 James E. Dale , Richard Wunsch , Anthony Whitworth , Jan Palous

The turbulent motion within molecular clouds is a key factor controlling star formation. Turbulence supports molecular cloud cores from evolving to gravitational collapse and hence sets a lower bound on the size of molecular cloud cores in…

Solar and Stellar Astrophysics · Physics 2015-06-23 Yang Gao , Haitao Xu , Chung K. Law

We investigate the influence of the external tidal field of a dark matter halo on the dynamical evolution of star clusters using direct N-body simulations, where we assume that the halo is described by a Navarro, Frenk & White mass profile…

Astrophysics of Galaxies · Physics 2009-09-28 A. K. Praagman , J. R. Hurley , C. Power

Equations for dislocation evolution bridge the gap between dislocation properties and continuum descriptions of plastic behavior of crystalline materials. Computer simulations can help us verify these evolution equations and find their…

Materials Science · Physics 2020-11-11 Kamyar M. Davoudi , Joost J. Vlassak

Understanding the influence of dark energy on the formation of structures is currently a major challenge in Cosmology, since it can distinguish otherwise degenerated viable models. In this work we consider the Top-Hat Spherical-Collapse…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-19 D. Herrera , I. Waga , S. E. Jorás

The gravitational slip parameter is an important discriminator between large classes of gravity theories at cosmological and astrophysical scales. In this work we use a combination of simulated information of galaxy cluster mass profiles,…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-27 Lorenzo Pizzuti , Ippocratis D. Saltas , Santiago Casas , Luca Amendola , Andrea Biviano

We investigate spherically symmetric gravitational collapse of thick matter shell without radiation in the Einstein gravity with cosmological constant. The orbit of the infalling thick matter is determined by imposing an equation of state…

General Relativity and Quantum Cosmology · Physics 2023-01-10 Shuichi Yokoyama