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Session 6 - Evolution, Survey and Clusters of Galaxies.
Display session, Monday, June 10
Tripp Commons,

[6.14] A Theoretical Investigation of Two-Body Relaxation in Rotating Systems

J. S. Arabadjis, D. O. Richstone (U. Michigan)

The evolution of dense rotating systems under the influence of two-body relaxation was studied through the use of N-body simulations. The initial configuration for each experiment was an isotropic Kuzmin-Kutuzov model sampled for 3000 bodies. We looked at two rotational states, one in which the system is non-rotating and spherical (Hénon's isochrone), and the other a rotationally flattened system with a 3.3:1 axis ratio. Each model was run with equal-mass stars and repeated using a Salpeter mass function. The simulations were also performed after adding a central non-accreting black hole of mass M/M_sys=0.05 to the center of the system. Hernquist's treecode was utilized to simulate the dynamical evolution. It was found that in models containing stars of different masses the evolution is driven by mass segregation. Cluster rotation has a mild effect on the evolution, with flattening in the isotropic models decreasing at most Lagrangian radii as the system evolves, consistent with Fokker-Planck calculations. Surprisingly, angular momentum transport appears to be directed toward the halo of the system in equal mass models and toward the core in multi-mass models. The increase of core angular momentum at the expense of the halo causes a moderate flattening at small r.

Program listing for Monday