Black Hole Binary Dynamics.pdf

BLACK HOLE BINARY DYNAMICS SVERRE J AARSETH Institute of Astronomy, Madingley Road, Cambridge CB3 0HA E-mail: sverre@ast.cam.ac.uk Abstract. We discuss a new N-body simulation method for studying black hole binary dynamics. This method avoids previous numerical problems due to large mass ratios and trapped orbits with short periods. A treatment of relativistic effects is 2 included when the associated time-scale becomes small. Preliminary results with up 0 to N = 2.4 ×105 particles are obtained showing systematic eccentricity growth until 0 2 the relativistic regime is reached, with subsequent coalescence in some cases. t c O 1. Introduction 4 1 The problem of the formation and dynamical evolution of a black hole v (BH) binary with massive components is of considerable topical in- 6 1 terest. Several previous efforts employed direct integration methods to 1 elucidate the behaviour of such systems but applications to galactic 0 nuclei pose severe limitations with regard to the particle number which 1 can be investigated. The formation is usually envisaged as the end 2 0 product of two separate galactic nuclei (or one being a dwarf galaxy) / spiralling together by dynamical friction, but there are other scenarios. h p Notwithstanding the particle number limitations imposed by the - need for accurate numerical treatment, much can b