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Related papers: Radially anisotropic systems with $r^{-\alpha}$ fo…

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We continue to investigate the dynamics of collisionless systems of particles interacting via additive $r^{-\alpha}$ interparticle forces. Here we focus on the dependence of the radial-orbit instability on the force exponent $\alpha$. By…

Astrophysics of Galaxies · Physics 2017-04-13 Pierfrancesco Di Cintio , Luca Ciotti , Carlo Nipoti

We have investigated the stability of a set of non-rotating anisotropic spherical models with a phase-space distribution function of the Osipkov-Merritt type. The velocity distribution in these models is isotropic near the center and…

Astrophysics · Physics 2009-10-30 Andres Meza , Nelson Zamorano

In the context of the study of the properties of the mutual mass distribution of the bright and dark matter in elliptical galaxies, present a family of two-component, spherical, self-consistent galaxy models, where one density distribution…

Astrophysics · Physics 2009-10-31 L. Ciotti

We discuss some contradictions found in the literature concerning the problem of stability of collisionless spherical stellar systems which are the simplest anisotropic generalization of the well-known polytrope models. Their distribution…

Solar and Stellar Astrophysics · Physics 2015-05-27 E. V. Polyachenko , V. L. Polyachenko , I. G. Shukhman

It is well known that the density and anisotropy profile in the inner regions of a stellar system with positive phase-space distribution function are not fully independent. Here we study the interplay between density profile and orbital…

Astrophysics · Physics 2009-11-13 Luca Ciotti , Lucia Morganti

We have performed a series of high resolution N-body experiments on a Connection Machine CM-5 in order to study the stability of collisionless self-gravitating spherical systems. We interpret our results in the framework of symplectic…

Astrophysics · Physics 2015-06-24 J. Perez , J-M Alimi , J-J Aly , H. Scholl

Following earlier authors, we re-examine constraints on the radial velocity anisotropy of generic stellar systems using arguments for phase space density positivity, stability, and separability. It is known that although the majority of…

Astrophysics of Galaxies · Physics 2015-06-19 Jeremy A. Barber , Hongsheng Zhao

We study the stability of rotating collisionless self-gravitating spherical systems by using high resolution N-body experiments on a Connection Machine CM-5. We added rotation to Ossipkov-Merritt (hereafter OM) anisotropic spherical systems…

Astrophysics · Physics 2009-10-31 J. -M. Alimi , J. Perez , A. Serna

We study the dynamical properties of spherical galaxies with surface luminosity profile described by the R^{1/m}-law, in which a variable degree of orbital anisotropy is allowed. The parameter m for the present models covers the range…

Astrophysics · Physics 2007-05-23 L. Ciotti , B. Lanzoni

We study the stability of a family of spherical equilibrium models of self-gravitating systems, the so-called $\gamma-$models with Osipkov-Merritt velocity anisotropy, by means of $N-$body simulations. In particular, we analyze the effect…

Astrophysics of Galaxies · Physics 2020-04-01 Pierfrancesco Di Cintio , Lapo Casetti

We investigate the effect of radial anisotropy on the rate of orbit decay in parabolic encounters of identical spherical galaxies. Our galaxy models have Hernquist density profiles and Osipkov--Merritt velocity distributions. We find that…

Astrophysics of Galaxies · Physics 2023-12-04 Lucas Saleh , Joshua E. Barnes

Simple analytical models, such as the Hernquist model, are very useful tools to investigate the dynamical structure of galaxies. Unfortunately, most of the analytical distribution functions are either isotropic or of the Osipkov-Merritt…

Astrophysics · Physics 2009-11-07 Maarten Baes , Herwig Dejonghe

A simple algorithm is presented for the calculation of the projected line-of-sight velocity profiles (VPs) of non-rotating anisotropic spherical stellar dynamical models with a phase-space distribution function of the Osipkov-Merritt type.…

Astrophysics · Physics 2015-06-24 C. M. Carollo , P. T. de Zeeuw , R. P. van der Marel

We present a method to investigate the radial stability of a spherical anisotropic system that hosts a central supermassive black hole (SBH). Such systems have never been tested before for stability, although high anisotropies have been…

Astrophysics · Physics 2008-11-26 P. Buyle , E. Van Hese , S. De Rijcke , H. Dejonghe

Context. We have investigated the structure and kinematics of triaxial final models formed due to radial-orbit instability from a set of equilibrium anisotropic spherical systems of the Osipkov-Merritt type. Aims. We show that the…

Astrophysics · Physics 2008-11-18 Piffl T. , Sotnikova N. Ya

It is well known that the simple criterion proposed originally by Polyachenko and Shukhman (1981) for the onset of the radial orbit instability, although being generally a useful tool, faces significant exceptions both on the side of mildly…

Astrophysics · Physics 2016-08-30 M. Trenti , G. Bertin

An iterative approach is used to construct spherically symmetric equilibrium models with an anisotropic velocity distribution. The potentialities of the method have been tested on models with known distribution functions, the…

Astrophysics · Physics 2009-11-13 N. Ya. Sotnikova , S. A. Rodionov

Stationary stellar systems with radially elongated orbits are subject to radial orbit instability -- an important phenomenon that structures galaxies. Antonov (1973) presented a formal proof of the instability for spherical systems in the…

Astrophysics of Galaxies · Physics 2017-07-26 E. V. Polyachenko , I. G. Shukhman

Two distinct non-singular interior models that describe anisotropic spherical configurations are presented in this work. We develop the Einstein field equations and the associated mass function in accordance with a static spherical…

General Relativity and Quantum Cosmology · Physics 2025-10-10 M. Sharif , Tayyab Naseer , Hira Shadab

We study a new class of equilibrium two-parametric distribution functions of spherical stellar systems with radially anisotropic velocity distribution of stars. The models are less singular counterparts of the so called generalized…

Astrophysics of Galaxies · Physics 2015-06-16 E. V. Polyachenko , V. L. Polyachenko , I. G. Shukhman
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