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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 present a class of exact solutions of Einstein's gravitational field equations describing spherically symmetric and static anisotropic stellar type configurations. The solutions are obtained by assuming a particular form of the…

General Relativity and Quantum Cosmology · Physics 2017-10-04 T. Harko , M. K. Mak

We add to the lore of spherical, stellar-system models a two-parameter family with an anisotropic velocity dispersion, and a central point mass (``black hole''). The ratio of the tangential to radial dispersions, is constant--and…

Astrophysics · Physics 2009-10-28 Mordehai Milgrom

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

The interest in studying relativistic compact objects play an important role in modern astrophysics with an aim to understand several astrophysical issues. It is therefore natural to ask for internal structure and physical properties of…

General Physics · Physics 2018-09-19 S. K. Maurya , Ayan Banerjee , Y. K. Gupta

We present new equilibrium component distribution functions that depend on three analytic integrals in a Stackel potential, and that can be used to model stellar discs of galaxies. These components are generalizations of two-integral ones…

Astrophysics · Physics 2008-11-26 B. Famaey , K. Van Caelenberg , H. Dejonghe

We present a class of exact solutions of Einstein's gravitational field equations describing spherically symmetric and static anisotropic stellar type configurations. The solutions are obtained by assuming a particular form of the…

General Relativity and Quantum Cosmology · Physics 2009-11-07 M. K. Mak , T. Harko

The density profiles and other quantities of physical interest for spherically symmetric systems are computed by assuming that a collisionless stellar gas may relax to the non-Gaussian power law distribution suggested by the nonextensive…

Astrophysics · Physics 2011-07-19 J. A. S. Lima , R. E. de Souza

A simple classification is given of the anisotropic relativistic star models, resembling the one of charged isotropic solutions. On the ground of this database, and taking into account the conditions for physically realistic star models, a…

General Relativity and Quantum Cosmology · Physics 2018-01-24 B. V. Ivanov

We demonstrate the existence of distribution functions that can be used to represent spherical massless cored stellar systems embedded in cuspy dark matter halos with constant mildly tangential velocity anisotropy. In particular, we derive…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Maarten A. Breddels , Amina Helmi

This paper provides two families of flexible and simple galaxy models. Representatives of many of the families possess the important cosmological cusps, with the density behaving like 1/r or 1/r^1.33 or 1/r^1.5 at small radii. The density…

Astrophysics · Physics 2007-05-23 J. H. an , N. W. Evans

General criteria to check the positivity of the distribution function (phase-space consistency) of stellar systems of assigned density and anisotropy profile are useful starting points in Jeans-based modeling. Here we substantially extend…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Luca Ciotti , Lucia Morganti

We describe a practical method for constructing axisymmetric two-integral galaxy models (with distribution functions of the form f(E,L_z), in which E is the orbital energy, and L_z is the vertical component of the angular momentum), based…

Astrophysics · Physics 2009-11-07 E. K. Verolme , P. T. de Zeeuw

We propose an analytical method to describe a matter density profile near a galaxy center. The description is based on the study of the distribution function of particles over possible trajectories. We establish a relation between the…

General Relativity and Quantum Cosmology · Physics 2022-11-17 A. D. Kapustin , S. A. Paston

We study systematically stationary solutions to the coupled Vlasov and Poisson equations which have `self-similar' or scaling symmetry in phase space. In particular, we find analytically {\it all} spherically symmetric distribution…

Astrophysics · Physics 2015-06-24 R. N. Henriksen , Lawrence M. Widrow

There is good evidence from N-body simulations that the velocity distribution in the outer parts of halos is radially anisotropic, with the kinetic energy in the radial direction roughly equal to the sum of that in the two tangential…

Astrophysics · Physics 2007-05-23 N. W. Evans , J. An

We perform a theoretical analysis of the observational dependence between angular momentum of the galaxy clusters and their mass (richness), based on the method introduced in our previous paper. For that we obtain the distribution function…

Astrophysics of Galaxies · Physics 2017-12-20 V. A. Stephanovich , W. Godłowski

Following the seminal result of An & Evans, known as the central density slope-anisotropy theorem, successive investigations unexpectedly revealed that the density slope-anisotropy inequality holds not only at the center, but at all radii…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Luca Ciotti , Lucia Morganti

Dynamical properties of spherically symmetric galaxy models where both the stellar and total mass density distributions are described by the Jaffe (1983) profile (with different scale-lenghts and masses), are presented. The orbital…

Astrophysics of Galaxies · Physics 2017-12-20 L. Ciotti , A. Ziaee Lorzad

The standard method of modelling axisymmetric stellar systems begins from the assumption that mass follows light. The gravitational potential is then derived from the luminosity distribution, and a unique two-integral distribution function…

Astrophysics · Physics 2009-10-28 David Merritt