MOCCA Code for Star Cluster Simulations - IV. A new Scenario for
  Intermediate Mass Black Hole Formation in Globular Clusters
  We discuss a new scenario for the formation of intermediate mass black holes
in dense star clusters. In this scenario, intermediate mass black holes are
formed as a result of dynamical interactions of hard binaries containing a
stellar mass black hole, with other stars and binaries. We discuss the
necessary conditions to initiate the process of intermediate mass black hole
formation and the influence of an intermediate mass black hole on the host
global globular cluster properties. We discuss two scenarios for intermediate
mass black hole formation. The SLOW and FAST scenarios. They occur later or
earlier in the cluster evolution and require smaller or extremely large central
densities, respectively. In our simulations, the formation of intermediate mass
black holes is highly stochastic. In general, higher formation probabilities
follow from larger cluster concentrations (i.e. central densities). We further
discuss possible observational signatures of the presence of intermediate mass
black holes in globular clusters that follow from our simulations. These
include the spatial and kinematic structure of the host cluster, possible
radio, X-ray and gravitational wave emissions due to dynamical collisions or
mass-transfer and the creation of hypervelocity main sequence escapers during
strong dynamical interactions between binaries and an intermediate mass black
hole. All simulations discussed in this paper were performed with the MOCCA
Monte Carlo code. MOCCA accurately follows most of the important physical
processes that occur during the dynamical evolution of star clusters but, as
with other dynamical codes, it approximates the dissipative processes connected
with stellar collisions and binary mergers.
