Dynamics of Intermediate Mass Black Holes in Star Clusters and Galactic Nuclei

X-ray observations of starburst and interacting galaxies have revealed a class of 
ultra-luminous X-ray sources (ULX), whose luminosities exceed the Eddington luminosities of stellar mass black holes by orders of magnitude, making them good  candidates for intermediate mass black holes (IMBHs). If real, IMBHs would provide an  important link between the supermassive black holes in galactic centers and ''normal''  stellar mass black holes. 
In my talk, I will present results of N-body simulations of the dynamical evolution
of young star clusters. Conditions under which run-away merging can lead to the growth of intermediate-mass black holes are illustrated for low and high mass clusters. I will then show how clusters containing IMBHs evolve at later times and discuss evidence that some galactic globular clusters host IMBHs. I will  finally discuss if the recently discovered hyper-velocity stars in the galactic halo were  ejected by inspiralling IMBHs in the galactic center.