N-body simulations of globular clusters in tidal fields: Effects of
  intermediate-mass black holes
  Intermediate-mass black holes (IMBHs) may provide the missing link to
understanding the growth of supermassive black holes in the early Universe.
Some formation scenarios predict that IMBHs could have formed by runaway
collisions in globular clusters (GCs). Understanding the influence of an IMBH
in the center of a GC on its environment might provide indirect detection
methods. Our goal is to test the effects of different initial compositions of
GCs on their evolution in a tidal field. We pin down the crucial observables
that indicate the presence of an IMBH at the center of the cluster. In addition
to central IMBHs, we also consider the effects of different stellar-mass black
hole retention and stellar binary fractions. We performed a set of 22 N-body
simulations and varied particle numbers, IMBH masses, stellar-mass black-hole
retention fractions, and stellar binary fractions. These models are all run in
an external tidal field to study the effect of black holes on the cluster mass
loss, mass function, and life times. Finally, we compared our results with
observational data. We found that a central massive black hole increases the
escape rate of high-mass stars from a star cluster, implying that the relative
depletion of the mass function at the low-mass end proceeds less rapidly.
Furthermore, we found a similar behavior for a cluster hosting a high number of
stellar-mass black holes instead of one massive central IMBH. The presence of
an IMBH also weakly affects the fraction of the cluster mass that is
constituted by stellar remnants, as does the presence of primordial binaries.
We compared our simulations with observational data from the literature and
found good agreement between our models and observed mass functions and
structural parameters of GCs. We exploited this agreement to identify GCs that
could potentially host IMBHs.
