AAS 195th Meeting, January 2000
Session 7. Galaxy Structures and Dynamics: Models and Observations
Display, Wednesday, January 12, 2000, 9:20am-6:30pm, Grand Hall

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[7.03] Orbital and Structural Evolution of Triaxial Galaxies.

K. Holley-Bockelmann, J. C. Mihos (Case Western Reserve University), S. Sigurdsson (Pennsylvania State University), R. Stanek (Case Western Reserve University)

The shape of many elliptical galaxies may be significantly triaxial. Even a mildly triaxial potential has profound effects on the orbital content of the stars and dark matter, creating entire families of orbits which do not exist in the spherical regime. However, since the intrinsic shape of the elliptical is dictated by the time average of its orbital content, the shape of the galaxy may change with time, or with radius, as the stellar orbits respond to a changing potential. For example, the boxlike orbits that strongly characterize a triaxial galaxy may undergo stochastic evolution with the addition of a central mass - forcing the system into an axisymmetric one.

We use numerical simulations of realistic, self-consistent triaxial galaxies to determine the degree to which the growth of a massive central black hole drives the dynamical evolution of these systems. We compare cuspy Hernquist models with and without a central black hole. We analyze the evolution of structural properties and the stability of orbit families as a function of time and radius.

This work has been sponsored by a grant from the NASA Astrophysics Theory Program (NAG5-7019).

The author(s) of this abstract have provided an email address for comments about the abstract: kelly@eor.astr.cwru.edu

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