Secular instabilities of stellar systems: slow mode approach
Evgeny, POLYACHENKO
Institute of Astronomy, Moscow
Résumé :
Stellar systems of two different scales are discussed.
The first ones are disks and spheres of ~1pc in size
located around massive black holes in centers of
galaxies. They exhibit secular
evolution on slow timescales of the order of inverse
precession frequency. A new instability due to the
presence of a loss cone caused by the black hole
is found. The mechanism of AGN fuel support based on
this instability must be more efficient than one based
on the conventional collisional relaxation.
The second systems are galactic stellar disks. It is
argued that the usual (fast) bar mode can be treated
as a slow mode in a disk of stellar orbits.
The enhancement of the mode is produced due to
interaction with stars at corotation and OLR.
