Evolution of Star Clusters near the Galactic Center: Fully Self-consistent N-body Simulations

We have performed fully self-consistent N -body simulations of star clusters near the Galactic center (GC). Such simulations have not been performed because it is the difficult to perform fast and accurate simulations of large-N systems using conventional methods. We used the Bridge code, which integrates the parent galaxy using the tree algorithm and the star cluster using the fourth-order Hermite scheme with individual timestep. The interaction between the parent galaxy and the star cluster is calculate with the tree algorithm. We investigated the orbital and internal evolutions of the star clusters using this Bridge scheme and compared the result with those of “traditional” simulations, in which the orbital evolution of the star cluster is calculated analytically from the dynamical friction formula. We found that the inspiral timescale of the star cluster is shorter than that obtained with traditional simulations. The timescale problem of the star cluster inspiral scenario is not so severe as previously suggested. Subject headings: galaxy: star clusters — Galaxy: center, kinematics and dynamics — methods: numerical — stellar dynamics