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Related papers: Some improvements to the spherical collapse model

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We study the joint effect of tidal torques and dynamical friction on the collapse of density peaks solving numerically the equations of motion of a shell of barionic matter falling into the central regions of a cluster of galaxies. We…

Astrophysics · Physics 2007-05-23 A. Del Popolo , M. Gambera

We study the effect of tidal torques on the collapse of density peaks through the equations of motion of a shell of barionic matter falling into the central regions of a cluster of galaxies. We calculate the time of collapse of the…

Astrophysics · Physics 2007-05-23 A. Del Popolo , M. Gambera

We solve numerically the equations of motion for the collapse of a shell of baryonic matter falling into the central regions of a cluster of galaxies, taking into account of the presence of the substructure inducing dynamical friction. The…

Astrophysics · Physics 2007-05-23 A. Del Popolo , M. Gambera , V. Antonuccio-Delogu

In this study, we build upon the findings of Del Popolo et al. (2013) by further analyzing the influence of dynamical friction on the evolution of cosmological perturbations within the framework of the spherical collapse model (SCM) in a…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-11 A. Del Popolo , Saeed Fakhry , Maryam Shiravand , Morgan Le Delliou

We explore the impact of dynamical friction on scales where the linear growth factor and the spherical collapse model can be applied and show its influence on the evolution of perturbations. In particular, considering smooth and clustering…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-25 Francesco Pace , Orlando Luongo , Antonino Del Popolo

We solve numerically the equations of motion for the collapse of a shell of baryonic matter, made of galaxies and substructure of $ 10^{6} M_{\odot}- 10^{9} M_{\odot}$, falling into the central regions of a cluster of galaxies taking…

Astrophysics · Physics 2007-05-23 A. Del Popolo , M. Gambera

We investigate some modifications to the Press & Schechter (1974) (PS) prescription resulting from shear and tidal effects. These modifications rely on more realistic treatments of the collapse process than the standard approach based on…

Astrophysics · Physics 2011-05-23 Edouard Audit , Romain Teyssier , Jean-Michel Alimi

Many Local Group dwarf spheroidal galaxies are found in the Galactic halo along great circles in the sky. Some of these stellar systems are thought to be the fragments of larger parent galaxies which have once intruded into and were torn…

Astrophysics · Physics 2008-11-26 M. Fellhauer , D. N. C. Lin

Two puzzles associated with open clusters have attracted a lot of attention -- their formation, with densities and velocity dispersions that are not too different from those of the star forming regions in the Galaxy, given that the observed…

Astrophysics of Galaxies · Physics 2015-06-15 K. Indulekha

We study, for the first time, how shear and angular momentum modify typical parameters of the spherical collapse model, in dark energy dominated universes. In particular, we study the linear density threshold for collapse…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-04 A. Del Popolo , F. Pace , J. A. S. Lima

We study the effect of the dynamical friction induced by the presence of substructure on the statistics of the collapse of density peaks. Applying the results of a former paper we show that within high density environments, like rich…

Astrophysics · Physics 2009-10-22 S. Colafrancesco , V. Antonuccio-Delogu , A. Del Popolo

We study the evolution of globular clusters with mass spectra under the influence of the steady Galactic tidal field, including the effects of velocity anisotropy. Similar to single-mass models, velocity anisotropy develops as the cluster…

Astrophysics · Physics 2009-10-31 K. Takahashi , H. M. Lee

The main goal of this paper is to set up a numerical laboratory for the study of the slow evolution of the density and of the pressure tensor profiles of an otherwise collisionless stellar system, as a result of the interactions with a…

Astrophysics · Physics 2009-11-07 G. Bertin , T. Liseikina , F. Pegoraro

Understanding the evolution of stellar clusters in an evolving tidal field is critical for studying the disruption of stellar clusters in a cosmological context. We systematically characterise the response of stellar clusters to tidal…

Astrophysics of Galaxies · Physics 2019-05-15 Jeremy J. Webb , Marta Reina-Campos , J. M. Diederik Kruijssen

Tidal forces acting on galaxies in clusters lead to a strong dynamical evolution. In order to quantify the amount of evolution, I run self-consistent N-body simulations of disk galaxies for a variety of models in the hierarchically forming…

Astrophysics · Physics 2008-11-26 Oleg Y. Gnedin

Non-spherical dynamical approximations and models for the gravitational collapse are used to extend the well-known Press \& Schechter (PS) approach, in order to determine analytical expressions for the mass function of cosmic structures.…

Astrophysics · Physics 2009-09-25 Pierluigi Monaco

Observed molecular clouds often appear to have very low star formation efficiencies and lifetimes an order of magnitude longer than their free-fall times. Their support is attributed to the random supersonic motions observed in them. We…

Astrophysics · Physics 2010-10-28 Ralf S. Klessen , Fabian Heitsch , Mordecai-Mark Mac Low

Generally, merger likelihood increases in denser environments; however, the large relative velocities at the centres of dense clusters are expected to reduce the likelihood of mergers for satellite galaxies. Tidal features probe the recent…

Dynamical friction and tidal disruption are effective mechanisms of evolution of globular cluster systems, especially in non-axysimmetric galaxies with a central compact nucleus. With a semi-analytical approach based on the knowledge of the…

Astrophysics · Physics 2016-08-30 R. Capuzzo-Dolcetta , A. Tesseri

It is well known that departure from sphericity in the geometry of primordial dark matter halos modifies their mass function. The ellipsoidal collapse model yields a better agreement with simulations of hierarchical clustering than the…

Astrophysics of Galaxies · Physics 2025-04-08 Pierre Dumond , Gilles Chabrier
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