Compact Massive Objects in galactic centers

The large majority of galaxies of all morphological types show the presence of a Compact Massive Object (CMO) in their center. Brighter galaxies, usually giant ellipticals, borrow central massive and supermassive black holes (MBHs), while fainter ellipticals show nucleated cores. Spiral galaxies often have at their center very compact star clusters, called Nuclear Star Clusters (NSCs). Also the coexistence of both a massive black hole surrounded by a dense, massive star cluster, occurs in nature. An example of this is our own Galaxy where a 4 million solar masses black hole is embedded in a more than 10 million solar masses NSC. The origin of these CMOs in galaxies is still under study. In this talk I will discuss one possible explanation for the origin of NSCs with its implications on the genesis and evolution of MBHs.