A direct N-body model of core-collapse and core oscillations
  We report on the results of a direct N-body simulation of a star cluster that
started with N = 200 000, comprising 195 000 single stars and 5 000 primordial
binaries. The code used for the simulation includes stellar evolution, binary
evolution, an external tidal field and the effects of two-body relaxation. The
model cluster is evolved to 12 Gyr, losing more than 80% of its stars in the
process. It reaches the end of the main core-collapse phase at 10.5 Gyr and
experiences core oscillations from that point onwards -- direct numerical
confirmation of this phenomenon. However, we find that after a further 1 Gyr
the core oscillations are halted by the ejection of a massive binary comprised
of two black holes from the core, producing a core that shows no signature of
the prior core-collapse. We also show that the results of previous studies with
N ranging from 500 to 100 000 scale well to this new model with larger N. In
particular, the timescale to core-collapse (in units of the relaxation
timescale), mass segregation, velocity dispersion, and the energies of the
binary population all show similar behaviour at different N.
