The Evolution of Cuspy Triaxial Galaxies Harboring Central Black Holes

We use numerical simulations to study the evolution of triaxial ellipticalgalaxies with central black holes. In contrast to earlier numerical studieswhich used galaxy models with central density ``cores,'' our galaxies havesteep central cusps, like those observed in real ellipticals. As a black holegrows in these cuspy triaxial galaxies, the inner regions become rounder owingto chaos induced in the orbit families which populate the model. At largerradii, however, the models maintain their triaxiality, and orbital analysesshow that centrophilic orbits there resist stochasticity over many dynamicaltimes. While black hole induced evolution is strong in the inner regions ofthese galaxies, and reaches out beyond the nominal ``sphere of influence'' of ablack hole, our simulations do not show evidence for a rapid {\it global}transformation of the host. The triaxiality of observed elliptical galaxies istherefore not inconsistent with the presence of supermassive black holes attheir centers.Comment: 15 pages, 7 figures (1 color). Accepted for publication in Ap