Star Cluster Collapse and Massive Black Hole

A cluster of compact objects (neutron stars and/or black holes) may mimic the presence of a super-massive black hole (SBH) at the center of the Galaxy. The cluster, with eventually a less massive black hole at its center, could be the remnant of a more massive cluster which has lost part of its mass. We use simple dynamical considerations to derive a lower limit to the mass of the black hole at the cluster center.