AAS 196th Meeting, June 2000
Session 21. Supermassive Blackhole Research and Advances with STIS
Topical Session Oral, Tuesday, June 6, 2000, 8:30-10:00am, 10:45am-12:30pm, 2:00-3:30pm, 3:45-5:30pm, Lilac Ballroom

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[21.24] Dynamics of Eccentric Nuclear Disks

T.S. Statler (Ohio U.)

HST observations suggest that eccentric disks may be common in the nuclei of galaxies containing supermassive black holes. The nearest example, M31, shows a double brightness peak and an asymmetric rotation curve, both of which are consistent with a simple stellar disk model introduced by Tremaine (1995). Such a disk may be a long-lived structure, if the gravitational effects of the disk itself (and the surrounding bulge) can conspire with the orbital dynamics to make the entire disk precess uniformly; the construction of realistic models for these structures is a new challenge for dynamicists. I will summarize recent work on (i) the orbital content of eccentric disks; (ii) self-consistent equilibria and observable properties; and (iii) simulations of dynamical evolution. Dynamically cool disks, such as that proposed by Tremaine, must be dominated by stars on quasiperiodic orbits whose periodic parents are nearly elliptical orbits aligned with the disk. It is easy to show that this sequence of ``backbone'' orbits must follow a steep eccentricity gradient through the densest part of the disk, which reverses the arrangement of pericenter and apocenter with respect to the central mass. Stars making up the inner part of the density concentration will be at apocenter, while stars making up the outer part will be at pericenter. Depending on the disk velocity dispersion, this effect may produce observable features in the kinematic profiles at HST resolution.

This work is supported by NSF CAREER grant AST 97-03036.

Tremaine, S. 1995, AJ, 110, 628

The author(s) of this abstract have provided an email address for comments about the abstract: statler@ohio.edu

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