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We present a synthesis of recent photometric and kinematic data for several of the most dark-matter dominated galaxies. There is a bimodal distribution in half-light radii, with stable star clusters always being smaller than $\sim30$pc,…

We study the distribution of dark matter in dwarf spheroidal galaxies by modelling the moments of their line-of-sight velocity distributions. We discuss different dark matter density profiles, both cuspy and possessing flat density cores.…

Astrophysics · Physics 2009-11-07 Ewa L. Lokas

We examine the coarse-grained phase-space density profiles of a set of recent, high-resolution simulations of galaxy-sized Cold Dark Matter (CDM) halos. Over two and a half decades in radius the phase-space density closely follows a…

Astrophysics · Physics 2009-11-06 James E. Taylor , Julio F. Navarro

The rotation curves of spiral galaxies exhibit a great diversity that challenge our understanding of galaxy formation and the nature of dark matter. Previous studies showed that in self-interacting dark matter (SIDM) models with a cross…

Astrophysics of Galaxies · Physics 2025-05-21 M. Grant Roberts , Manoj Kaplinghat , Mauro Valli , Hai-Bo Yu

We investigate spherically symmetric classes of anisotropic solutions within the realm of a schematic gravitational decoupling scheme, primarily decoupling through minimal geometric deformation, applied to non-rotating, ultra-compact,…

General Relativity and Quantum Cosmology · Physics 2024-08-23 Z. Yousaf , Kazuharu Bamba , Bander Almutairi , S. Khan , M. Z. Bhatti

By means of high-resolution N-body simulations we revisited the dissipationless collapse scenario for galaxy formation. We considered both single-component collapses and collapses of a cold stellar distribution in a live dark matter halo.…

Astrophysics · Physics 2009-11-11 C. Nipoti , P. Londrillo , L. Ciotti

If dark matter interacts, even weakly, via non-gravitational forces, simulations predict that it will be preferentially scattered towards the trailing edge of the halo during collisions between galaxy clusters. This will temporarily create…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-07 David Harvey , Andrew Robertson , Richard Massey , Jean-Paul Kneib

We study the distribution function (DF) of dark matter particles in haloes of mass range 10^{14}--10^{15}\Msun. In the numerical part of this work we measure the DF for a sample of relaxed haloes formed in the simulation of a standard…

If dark matter has a large self-interaction scattering cross section, then interactions among dark-matter particles will drive galaxy and cluster halos to become spherical in their centers. Work in the past has used this effect to rule out…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Annika H. G. Peter , Miguel Rocha , James S. Bullock , Manoj Kaplinghat

The analytical phase-space distribution function (DF) of spherical self--consistent galaxy (or cluster) models, embedded in a dark matter halo, where both density distributions follow the Hernquist profile, with different total masses and…

Astrophysics · Physics 2009-10-28 Luca Ciotti

The first paper of this series [J. Chem. Phys. 158, 034103 (2023)] demonstrated that excess entropy scaling holds for both fine-grained and corresponding coarse-grained (CG) systems. Despite its universality, a more exact determination of…

Chemical Physics · Physics 2023-01-18 Jaehyeok Jin , Kenneth S. Schweizer , Gregory A. Voth

After deducing the density profiles and gravitational potential functions of eight galaxies from the rotation velocity data from THINGS, we find that the density decreases exponentially with the potential in substantial regions of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Joshua Davidson , Sanjoy K. Sarker , Allen Stern

N-body simulations of dark matter halos show that the density profiles of halos behave as $\rho(r)\propto r^{-\alpha(r)}$, where the density logarithmic slope $\alpha \simeq 1\sim1.5$ in the center and $\alpha \simeq 3\sim 4$ in the outer…

Astrophysics · Physics 2015-05-13 Ding Ma , Ping He

Collapsing collisionless particle systems form gravitational bound halos with cuspy density profiles. Also hierarchical merging of these systems produce remnants with cuspy central density profiles. These results lead to the assumption of…

Astrophysics · Physics 2009-11-07 Marc Hemsendorf

In the present paper, we improve the "Extended Secondary Infall Model" (ESIM) of Williams et al. (2004) to obtain further insights on the cusp/core problem. The model takes into account the effect of ordered and random angular momentum,…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-04 A. Del Popolo , P. Kroupa

I review the up-to-date status on the properties of the Dark Matter density distribution around Galaxies. The rotation curves of spirals all conform to a same Universal profile which can be uniquely decomposed as the sum of an exponential…

Astrophysics · Physics 2007-05-23 Paolo Salucci

N-body simulations of collisionless collapse have offered important clues to the construction of realistic stellar dynamical models of elliptical galaxies. Such simulations confirm and quantify the qualitative expectation that rapid…

Astrophysics · Physics 2009-11-10 G. Bertin , M. Trenti

We provide a family of action-based distribution functions (DFs) for the double-power law family of densities often used to model galaxies. The DF itself is a double-power law in combinations of the actions, and reduces to the known limits…

Astrophysics of Galaxies · Physics 2015-06-23 A. A. Williams , N. W. Evans

We study clustering in a stochastic system of particles sliding down a fluctuating surface in one and two dimensions. In steady state, the density-density correlation function is a scaling function of separation and system size.This scaling…

Statistical Mechanics · Physics 2009-11-13 Mustansir Barma

We investigate the Hierarchical Gravitational Fragmentation scenario through numerical simulations of the prestellar stages of the collapse of a marginally gravitationally unstable isothermal sphere immersed in a strongly gravitationally…

Astrophysics of Galaxies · Physics 2015-10-26 Raúl Naranjo-Romero , Enrique Vázquez-Semadeni , Robert M. Loughnane