The Hernquist model revisited: Completely analytical anisotropic dynamical models
Abstract
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 OsipkovMerritt type, and hence basically onedimensional. We present three different families of anisotropic distribution functions that selfconsistently generate the Hernquist potentialdensity pair. These families have constant, increasing and decreasing anisotropy profiles respectively, and can hence represent a wide variety of orbital structures. For all of the models presented, the distribution function and the velocity dispersions can be written in terms of elementary functions. These models are ideal tools for a wide range of applications, in particular to generate the initial conditions for Nbody or Monte Carlo simulations.
 Publication:

Astronomy and Astrophysics
 Pub Date:
 October 2002
 DOI:
 10.1051/00046361:20021064
 arXiv:
 arXiv:astroph/0207233
 Bibcode:
 2002A&A...393..485B
 Keywords:

 galaxies: kinematics and dynamics;
 galaxies: structure;
 Astrophysics
 EPrint:
 14 pages, 7 figures, accepted for publication in A&