The collapse of gas discs in non-axisymmetric galaxy cores
Abstract
Description
Below a threshold energy, gas in the constant density core of a triaxial galaxy can find no simple non-intersecting periodic orbit to act as an attractor for its trajectory (El-Zant et al. 2003). If a disc of gas arriving from further out in the galaxy dissipates sufficient energy to fall below this threshold, it will thereafter collapse into the very centre. Such a mechanism may be relevant to the early growth of super-massive black holes at the Eddington limit and the appearance of the quasar phenomenon at high redshift. This process is self-limiting in the sense that, when the black hole mass has grown to a significant fraction of the core mass, simple angular momentum conserving orbits are restored and accretion reverts to the slow viscous mode. The mechanism depends upon the pre-existence of constant density cores in triaxial spheroidal galaxies.
8 pages, 8 figures, a movie of simulations may be viewed at http://www.astro.rug.nl/~sanders/movie.html, important reference to El-Zant et al. included with additional discussion
8 pages, 8 figures, a movie of simulations may be viewed at http://www.astro.rug.nl/~sanders/movie.html, important reference to El-Zant et al. included with additional discussion