Numerical simulations of AGN evolution
Abstract
In this paper we present numerical N-body calculations of the evolution model of active galactic nuclei (AGN), consisting of compact stellar cluster, supermassive black hole and gaseous accretion disc. Besides gravitational interactions between stars and between stars and the black hole, the dissipative interaction of stars with the gaseous accretion disc and contact stellar collisions were taken into account. As numerical simulations of real stellar clusters containing more than 108 stars are not yet technically attainable in direct N-body simulations, we develop scaling methods that allow us to extrapolate the results of numerical simulations performed with smaller particle numbers to real stellar systems. Specifically, in this work we derive the scaling formula for stellar collisions. We then introduce a tentative scheme for stellar inelastic collisions in our numerical model to roughly estimate their effect. The preliminary result is that in simulating AGN dense stellar clusters contact collisions should be taken into account, as the mass lost during collisions, even if added to the gaseous accretion disc, has a different regime of accretion than that for intact stars. Therefore, stellar collisions might considerably reduce the rate of the black hole mass growth.
- Publication:
-
Astronomical and Astrophysical Transactions
- Pub Date:
- August 2013
- Bibcode:
- 2013A&AT...28..151V
- Keywords:
-
- Accretion: accretion discs;
- Galaxies: nuclei;
- Galaxies: active;
- Celestial mechanics;
- Methods: numerical