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Related papers: Substructure effects on the collapse of density pe…

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We have developed a phenomenological turbulent model with one-dimensional (1D) simulation based on Reynolds decomposition. Using this method, we have systematically studied models with different effects of compression, mixing length…

High Energy Astrophysical Phenomena · Physics 2024-01-24 Shunsuke Sasaki , Tomoya Takiwaki

We generalize the small scale dynamics of the universe by taking into account models with an equation of state which evolves with time, and provide a complete formulation of the cluster virialization attempting to address the nonlinear…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-01 S. Basilakos , J. C. Bueno Sanchez , Leandros Perivolaropoulos

We examine the problem of the collapse and fragmentation of molecular clouds with a Gaussian density distribution with high resolution, double precision numerical simulations using the GADGET-2 code. To describe the thermodynamic properties…

Solar and Stellar Astrophysics · Physics 2026-02-27 F. Gomez-Ramirez , J. Klapp , Jorge L. Cervantes-Cota , G. Arreaga-Garcia , D. Bahena

Stars and more particularly massive stars, have a drastic impact on galaxy evolution. Yet the conditions in which they form and collapse are still not fully understood. In particular, the influence of the magnetic field on the collapse of…

Astrophysics of Galaxies · Physics 2015-05-27 P. Hennebelle , B. Commercon , M. Joos , R. S. Klessen , M. Krumholz , J. C. Tan , R. Teyssier

Star cluster formation and assembly occurs inside filamentary and turbulent molecular clouds, which imprints both spatial and kinematic substructure on the young cluster. In this paper, we quantify the amount and evolution of this…

Astrophysics of Galaxies · Physics 2025-07-02 Edwin Laverde-Villarreal , Alison Sills , Claude Cournoyer-Cloutier , Veronica Arias Callejas

We derive similarity solutions for the expansion of negative initial density perturbations \delta M/M \propto r^-s (s>0) in an Einstein-de Sitter universe filled with collisional baryonic gas and collisionless matter. The solutions are…

Astrophysics · Physics 2009-11-07 Leonid Chuzhoy , Adi Nusser

Gravitational collapse of the cylindrical elongated cloud is studied by numerical magnetohydrodynamical simulations. In the infinitely long cloud in hydrostatic configuration, small perturbations grow by the gravitational instability. The…

Astrophysics · Physics 2009-10-22 Kohji Tomisaka

The molecular component of the Galaxy is comprised of turbulent, magnetized clouds, many of which are self-gravitating and form stars. To understand how these clouds' evolution may depend on their level of turbulence, mean magnetization,…

Astrophysics · Physics 2009-10-31 Eve C. Ostriker , Charles F. Gammie , James M. Stone

We examine the distributions of eccentricities of orbits within mass distributions like those we see for galaxies and clusters. A comprehensive understanding of these orbital properties is essential to calculate the rates of physical…

Astrophysics · Physics 2009-10-31 Frank C. van den Bosch , Geraint F. Lewis , George Lake , Joachim Stadel

In the Cold Dark Matter (hereafter CDM) scenario even isolated density peaks contain a high fraction of small scale clumps having velocities larger than the average escape velocity from the structure. These clumps populate protoclusters,…

Astrophysics · Physics 2016-08-16 A. Del Popolo , M. Gambera , E. N. Ercan

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

It has been known for some time that rotating bars in galaxies slow due to dynamical friction against the halo. However, recent attempts to use this process to place constraints on the dark matter density in galaxies and possibly also to…

Astrophysics · Physics 2016-08-30 J. A. Sellwood

We systematically study the effects of collisions on the overall dynamical evolution of dense star clusters using Monte Carlo simulations over many relaxation times. We derive many observable properties of these clusters, including their…

Astrophysics · Physics 2009-11-13 Sourav Chatterjee , John M. Fregeau , Frederic A. Rasio

We study the detailed structure of galaxies at redshifts z > 2 using cosmological simulations with improved modeling of the interstellar medium and star formation. The simulations follow the formation and dissociation of molecular hydrogen,…

Astrophysics of Galaxies · Physics 2012-09-21 Marcel Zemp , Oleg Y. Gnedin , Nickolay Y. Gnedin , Andrey V. Kravtsov

In this paper, we analyze the dynamical evolution of quintessence dark energy induced by the collapse of dark matter halos. Different from other previous studies, we develop a numerical strategy which allows us to calculate the dark energy…

Cosmology and Nongalactic Astrophysics · Physics 2009-07-09 Qiao Wang , Zuhui Fan

The hierarchical mergers that form the haloes of dark matter surrounding galaxies, groups and clusters are not entirely efficient, leaving substantial amounts of dense substructure, in the form of stripped halo cores or `subhaloes',…

Astrophysics · Physics 2009-11-07 James E. Taylor , Arif Babul

Dynamical friction implies a consistency check on any system where dark matter particles are hypothesised to explain orbital dynamics requiring more mass under Newtonian gravity than is directly detectable. Introducing the assumption of a…

Astrophysics of Galaxies · Physics 2025-11-07 X. Hernandez , Pavel Kroupa

Numerical simulations of the dynamical friction suffered by a star cluster near the Galactic center have been performed with a parallelized tree code. Gerhard (2001) has suggested that dynamical friction, which causes a cluster to lose…

Astrophysics · Physics 2009-11-10 Sungsoo S. Kim , Mark Morris

The formation of galaxy clusters in hierarchically clustering universes is investigated by means of high resolution N-body simulations. The simulations are performed using a newly developed multi-mass scheme which combines a PM code with a…

Astrophysics · Physics 2007-05-23 A. Huss , B. Jain , M. Steinmetz

We studied the effects of cluster environments on galactic structures by using the TNG50 cosmological simulation and observed galaxies in the Fornax cluster. We focused on galaxies with stellar masses of $10^{8-12}M_{\odot}$ at z=0 that…