N-body simulation of a clumpy torus: application to active galactic   nuclei
  The gravitational properties of a torus are investigated. It is shown that a torus can be formed from test particles orbiting in the gravitational field of a central mass. In this case, a toroidal distribution is achieved because of the significant spread of inclinations and eccentricities of the orbits. To investigate the self-gravity of the torus we consider the $N$-body problem for a torus located in the gravitational field of a central mass. It is shown that in the equilibrium state the cross-section of the torus is oval with a Gaussian density distribution. The dependence of the obscuring efficiency on torus inclination is found. 
Elena Yu. Bannikova, Victor G. Vakulik, Alexey V. Sergeev
astro-ph.CO astro-ph.GA physics.class-ph