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In many investigations involving accretion on a central point mass, ranging from observational studies to cosmological simulations, including semi-analytical modelling, the classical Bondi accretion theory is the standard tool widely…

Astrophysics of Galaxies · Physics 2022-03-14 Antonio Mancino , Luca Ciotti , Silvia Pellegrini

In the solution of the Jeans equations for axisymmetric galaxy models the ``$b$-ansatz" is often adopted to prescribe the relation between the vertical and radial components of the velocity dispersion tensor, and close the equations.…

Astrophysics of Galaxies · Physics 2025-11-05 Leonardo De Deo , Luca Ciotti , Silvia Pellegrini

A two-component isothermal equilibrium model is applied to reproduce basic structural properties of dynamically hot stellar systems immersed in their massive dark haloes. The origin of the fundamental plane relation for giant ellipticals is…

Astrophysics · Physics 2015-06-24 Alexei G. Kritsuk

N-body simulations of dark matter halos show that the density is cusped near the center of the halo. The density profile behaves as $r^{-\gamma}$ in the inner parts, where $\gamma \simeq 1$ for the NFW model and $\gamma \simeq 1.5$ for the…

Astrophysics · Physics 2009-06-23 Ding Ma , Ping He

Dark matter mass density profiles and velocity distributions for a set of dwarf spheroidal galaxies (dSphs) have recently been obtained (F.Bezrukov, D.Gorbunov, E.Koreshkova arXiv:2412.20585) by performing a multi-parametric fit to the…

Astrophysics of Galaxies · Physics 2025-09-12 Fedor Bezrukov , Dmitry Gorbunov , Ekaterina Koreshkova

The Jeans equations give the second moments or stresses required to support a stellar population against the gravity field. A general solution of the Jeans equations for arbitrary axisymmetric scale-free densities in flattened scale-free…

Astrophysics · Physics 2015-06-24 N. W. Evans , R. M. Häfner , P. T. de Zeeuw

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 present a new method to construct fully self-consistent equilibrium models of multi-component disc galaxies similar to the Milky Way. We define distribution functions for the stellar disc and dark halo that depend on phase space position…

Astrophysics of Galaxies · Physics 2015-07-03 T. Piffl , Z. Penoyre , J. Binney

We carry out a systematic investigation of the total mass density profile of massive (Mstar>2e11 Msun) early-type galaxies and its dependence on galactic properties and host halo mass with the aid of a variety of lensing/dynamical data and…

We use the Jaffe model as a global mass distribution for the Galaxy and determine the circular velocity $v_c$ and the Jaffe radius $r_j$ using the satellites of the Galaxy, estimates of the local escape velocity of stars, the constraints…

Astrophysics · Physics 2009-10-28 Christopher S. Kochanek

The radial mass distribution of dark matter haloes is investigated within the framework of the spherical infall model. We present a new formulation of spherical collapse including non-radial motions, and compare the analytical profiles with…

Astrophysics · Physics 2009-11-10 Y. Ascasibar , G. Yepes , S. Gottloeber , V. Mueller

Various analytic expressions have been proposed for the density profile of dark matter halos. We consider six of these expressions for which the density profile has a power-law fall-off rho proportional to r^{-3} at large radii and a…

Astrophysics · Physics 2007-05-23 Lawrence M. Widrow

With SDSS galaxy data and halo data from up-to-date N-body simulations we construct a semi-empirical catalog (SEC) of early-type systems by making a self-consistent bivariate statistical match of stellar mass (M_star) and velocity…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Kyu-Hyun Chae , Andrey V. Kravtsov , Joshua A. Frieman , Mariangela Bernardi

We make a simple analytical study of radial profiles of dark matter structures, with special attention to the question of the central radial density profile. We let our theoretical assumptions be guided by results from numerical…

Astrophysics · Physics 2009-11-10 Steen H. Hansen

This paper introduces a new two-parameter family of dwarf spheroidal (dSph) galaxy models. The density distribution has a Plummer profile and falls like the inverse fourth power of distance in projection, in agreement with the star-count…

Astrophysics · Physics 2009-11-07 M. I. Wilkinson , J. Kleyna , N. W. Evans , G. Gilmore

We develop a flexible set of action-based distribution functions (DFs) for stellar haloes. The DFs have five free parameters, controlling the inner and outer density slope, break radius, flattening and anisotropy respectively. The DFs…

Astrophysics of Galaxies · Physics 2015-09-30 A. A. Williams , N. W. Evans

We present theoretical calculations for the differential distribution of stellar orbital eccentricity in a galaxy halo, assuming that the stars constitute a spherical, collisionless system in dynamical equilibrium with a dark matter halo.…

Astrophysics of Galaxies · Physics 2015-05-19 Kohei Hattori , Yuzuru Yoshii

We assemble a statistical set of global mass models for ~2,000 nearly spherical SDSS galaxies at a mean redshift of 0.12 based on their aperture velocity dispersions and newly derived luminosity profiles in conjunction with published…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Kyu-Hyun Chae , Mariangela Bernardi , Andrey V. Kravtsov

We present the results of a study of the average mass profile around galaxies using weak gravitational lensing. We use 45.5 deg^2 of R_C band imaging data from the Red-Sequence Cluster Survey (RCS) and define a sample of 1.2\times 10^5…

Astrophysics · Physics 2007-05-23 Henk Hoekstra , Howard K. C. Yee , Michael D. Gladders

We use the recently completed one billion particle Via Lactea II LambdaCDM simulation to investigate local properties like density, mean velocity, velocity dispersion, anisotropy, orientation and shape of the velocity dispersion ellipsoid,…