Intermediate-mass black holes in globular clusters: observations and
  simulations
  The study of intermediate-mass black holes (IMBHs) is a young and promising
field of research. Formed by runaway collisions of massive stars in young and
dense stellar clusters, intermediate-mass black holes could still be present in
the centers of globular clusters, today. Our group investigated the presence of
intermediate-mass black holes for a sample of 10 Galactic globular clusters. We
measured the inner kinematic profiles with integral-field spectroscopy and
determined masses or upper limits of central black holes in each cluster. In
combination with literature data we further studied the positions of our
results on known black-hole scaling relations (such as M_bh - sigma) and found
a similar but flatter correlation for IMBHs. Applying cluster evolution codes,
the change in the slope could be explained with the stellar mass loss occurring
in clusters in a tidal field over its life time. Furthermore, we present
results from several numerical simulations on the topic of IMBHs and integral
field units (IFUs). We ran N-body simulations of globular clusters containing
IMBHs in a tidal field and studied their effects on mass-loss rates and remnant
fractions and showed that an IMBH in the center prevents core collapse and
ejects massive objects more rapidly. These simulations were further used to
simulate IFU data cubes. For the specific case of NGC 6388 we simulated two
different IFU techniques and found that velocity dispersion measurements from
individual velocities are strongly biased towards lower values due to blends of
neighbouring stars and background light. In addition, we use the Astrophysical
Multipurpose Software Environment (AMUSE) to combine gravitational physics,
stellar evolution and hydrodynamics to simulate the accretion of stellar winds
onto a black hole.
