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Title: THE LOSS-CONE PROBLEM IN AXISYMMETRIC NUCLEI

We consider the problem of consumption of stars by a supermassive black hole (SBH) at the center of an axisymmetric galaxy. Inside the SBH sphere of influence, motion of stars in the mean field is regular and can be described analytically in terms of three integrals of motion: the energy E, the z-component of angular momentum L{sub z} , and the secular Hamiltonian H. There exist two classes of orbits, tubes and saucers; saucers occupy the low-angular-momentum parts of phase space and their fraction is proportional to the degree of flattening of the nucleus. Perturbations due to gravitational encounters lead to diffusion of stars in integral space, which can be described using the Fokker-Planck equation. We calculate the diffusion coefficients and solve this equation in the two-dimensional phase space (L{sub z} , H), for various values of the capture radius and the degree of flattening. Capture rates are found to be modestly higher than in the spherical case, up to a factor of a few, and most captures take place from saucer orbits. We also carry out a set of collisional N-body simulations to confirm the predictions of the Fokker-Planck models. We discuss the implications of our results for ratesmore » of tidal disruption and capture in the Milky Way and external galaxies.« less
Authors:
;  [1]
  1. School of Physics and Astronomy and Center for Computational Relativity and Gravitation, Rochester Institute of Technology, Rochester, NY (United States)
Publication Date:
OSTI Identifier:
22133938
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 774; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANGULAR MOMENTUM; AXIAL SYMMETRY; BLACK HOLES; COSMIC NUCLEI; DIFFUSION; DISTURBANCES; FOKKER-PLANCK EQUATION; HAMILTONIANS; INTEGRALS; LOSS CONE; MANY-BODY PROBLEM; MEAN-FIELD THEORY; MILKY WAY; ORBITS; PHASE SPACE; STARS