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Context. Merging compact objects such as binary black holes provide a promising probe for the physics of dark matter (DM). The gravitational waves emitted during inspiral potentially allow one to detect DM spikes around black holes. This is…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-23 Moritz S. Fischer , Laura Sagunski

For a rigid model satellite, Chandrasekhar's dynamical friction formula describes the orbital evolution quite accurately, when the Coulomb logarithm is chosen appropriately. However, it is not known if the orbital evolution of a real…

Astrophysics · Physics 2015-06-24 Michiko Fujii , Yoko Funato , Junichiro Makino

We study dynamical friction in the Newtonian regime of nonlocal gravity (NLG), which is a classical nonlocal generalization of Einstein's theory of gravitation. The nonlocal aspect of NLG simulates dark matter. The attributes of the…

General Relativity and Quantum Cosmology · Physics 2021-11-17 Mahmood Roshan , Bahram Mashhoon

We study the effect of Chandrasekhar and Holstmark's distribution of field fluctuations on the dynamics of N-body systems interacting via Coulomb or Newton gravitational force. We develop an approach based on statistical dynamics first…

Classical Physics · Physics 2014-01-21 Y. Chaffi , R. Casta , L. Brenig

Using analytic calculations and N-body simulations we show that in constant density (harmonic) cores, sinking satellites undergo an initial phase of very rapid (super-Chandrasekhar) dynamical friction, after which they experience no…

Astrophysics · Physics 2009-11-11 J. I. Read , Tobias Goerdt , Ben Moore , A. P. Pontzen , Joachim Stadel , George Lake

We present a new semi-analytic model for dynamical friction based on Chandrasekhar's formalism. The key novelty is the introduction of physically motivated, radially varying, maximum and minimum impact parameters. With these, our model…

Astrophysics of Galaxies · Physics 2015-10-28 James A. Petts , Alessia Gualandris , Justin I. Read

We present a simplified analytic approach to the problem of the spiraling of a massive body orbiting within the dark halo of a dwarf galaxy. This dark halo is treated as the core region of a King distribution of dark matter particles, in…

Astrophysics · Physics 2009-10-30 X. Hernandez , Gerard Gilmore

Dynamical friction governs the orbital decay of massive perturbers within galaxies and dark matter halos, yet its standard Chandrasekhar formulation fails in systems with cores of (roughly) constant density, where inspiral can halt or even…

Using time-dependent linear perturbation theory, we evaluate the dynamical friction force on a massive perturber M_p traveling at velocity V through a uniform gaseous medium of density rho_0 and sound speed c_s. This drag force acts in the…

Astrophysics · Physics 2009-10-31 Eve C. Ostriker

Chandrasekhar's most important contribution to stellar dynamics was the concept of dynamical friction. I briefly review that work, then discuss some implications of Chandrasekhar's theory of gravitational encounters for motion in galactic…

Astrophysics of Galaxies · Physics 2015-05-27 David Merritt

Dynamical friction arises from the interaction of a perturber and the gravitational wake it excites in the ambient medium. We study the effects of the presence of a boundary on dynamical friction by studying analytically the interaction of…

Astrophysics of Galaxies · Physics 2011-01-17 Fathi Namouni

The process of momentum and energy transfer between a massive body and a background medium it is moving through is known as dynamical friction (DF). It is key to our understanding of many astrophysical systems. We present a series of…

Astrophysics of Galaxies · Physics 2025-08-20 Ben Morton , Sadegh Khochfar , Jose Oñorbe

The nonextensive kinetic theory for degenerate quantum gases is discussed in the general relativistic framework. By incorporating nonadditive modifications in the collisional term of the relativistic Boltzmann equation and entropy current,…

General Relativity and Quantum Cosmology · Physics 2017-10-25 A. P. Santos , R. Silva , J. S. Alcaniz , J. A. S. Lima

Considering galaxies as self - gravitating systems of many collisionless particles allows to use methods of statistical mechanics inferring the distribution function of these stellar systems. Actually, the long range nature of the…

Cosmology and Nongalactic Astrophysics · Physics 2014-02-04 V. F. Cardone , M. P. Leubner , A. Del Popolo

Systems with long range interactions present generically the formation of quasi-stationary long-lived non-equilibrium states. These states relax to Boltzmann equilibrium following a dynamics which is not well understood. In this paper we…

Statistical Mechanics · Physics 2015-06-12 B. Marcos

We carry out a set of self-consistent N-body calculations to investigate how important the velocity anisotropy in non-spherical dark-matter haloes is for dynamical friction. For this purpose we allow satellite galaxies to orbit within…

Astrophysics · Physics 2009-11-10 Jorge Penarrubia , Andreas Just , Pavel Kroupa

We introduce a new micro-macro decomposition of collisional kinetic equations in the specific case of the diffusion limit, which naturally incorporates the incoming boundary conditions. The idea is to write the distribution function $f$ in…

Numerical Analysis · Mathematics 2012-02-10 Mohammed Lemou , Florian Méhats

We present a preliminary analysis of the effect of dynamical friction on the orbits of part of the globular clusters in our Galaxy. Our study considers an anisotropic velocity dispersion field approximated using the results of studies in…

We introduce a new micro/macro decomposition of collisional kinetic equations which naturally incorporates the exact space boundary conditions. The idea is to write the distribution fonction $f$ in all its domain as the sum of a Maxwellian…

Numerical Analysis · Mathematics 2011-02-22 Mohammed Lemou , Florian Méhats

Dynamical friction is often modeled with reasonable accuracy by the widely used Chandrasekhar formula. However, in some circumstances, Chandrasekhar's local and uniform approximations can break down severely. An astrophysically important…

Astrophysics of Galaxies · Physics 2022-07-06 Karamveer Kaur , Nicholas C. Stone