Abstract

We construct models of triaxial galactic nuclei containing central black holes using the method of orbital superposition, then verify their stability by advancing N-body realizations of the models forward in time. We assume a power-law form for the stellar density, ρ / r- , with γ = 1 and γ = 2; these values correspond approximately to the nuclear density profiles of bright and faint galaxies respectively. Equidensity surfaces are ellipsoids with fixed axis ratios. The central black hole is represented by a Newtonian point mass. We consider three triaxial shapes for each value of γ: almost prolate, almost oblate and maximally triaxial. Two kinds of orbital solution are attempted for each mass model: the first including only regular orbits, the second including chaotic orbits as well. We find that stable configurations exist, for both values of γ, in the maximally triaxial and nearly-oblate cases; however steady-state solutions in the nearly-prolate geometry could not be found. A large fraction of the mass, of order 50% or more, could be assigned to the chaotic orbits without inducing evolution. Our results demonstrate that triaxiality may persist even within the sphere of influence of the central black hole, and that chaotic orbits may constitute an important building block of galactic nuclei. (Refer to PDF file for exact formulas).

Publication Date

5-10-2004

Comments

Also archived in: arXiv:astro-ph/0212581 v1 31 Dec 2002 This work was supported by NSF grants AST 96-17088 and AST 00-71099 and by NASA grants NAG5-6037 and NAG5-9046.ISSN:1538-4357 Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.

Document Type

Article

Department, Program, or Center

School of Physics and Astronomy (COS)

Campus

RIT – Main Campus

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