Using Binaries in Globular Clusters to Catch Sight of Intermediate-Mass
  Black Holes
  The dynamical evolution of globular clusters (GCs) is tied to their binary
population, as binaries segregate to the cluster centre, leading to an
increased binary fraction in the core. This central overabundance of mainly
hard binaries can serve as a source of energy for the cluster and has a
significant effect on the observed kinematics, such as artificially increasing
the observed line-of-sight velocity dispersion.
  We analyse the binary fractions and distributions of 95 simulated GCs, with
and without an intermediate-mass black hole (IMBH) in their centre. We show
that an IMBH will not only halt the segregation of binaries towards the cluster
centre, but also, directly and indirectly, disrupt the binaries that segregate,
thus depleting binaries in the cluster core. We illustrate this by showing that
clusters with an IMBH have fewer binaries and flatter radial binary
distributions than their counterparts without one. These differences in the
binary fraction and distribution provide an additional indicator for the
presence of a central IMBH in GCs. In addition, we analyse the effects of the
binary fraction on the line-of-sight velocity dispersion in the simulated GCs
and find that binaries can cause an overestimation of up to $70\%$ of the
velocity dispersion within the core radius. Using recent VLT/MUSE observations
of NGC 3201 by Giesers et al. (2019), we find an overestimation of
$32.2\pm7.8\%$ in the velocity dispersion that is consistent with the
simulations and illustrates the importance of accurately accounting for the
binary population when performing kinematic or dynamical analysis.
