Can Galactic Nuclei Activity be Explained by Globular Cluster Mass   Accretion?
  Globular clusters can decay to the center of their mother galaxy carrying a quantity of mass sufficient to sustain the gravitational activity of a small pre-existing nucleus and to accrete it in a significant way. The AGN luminosity and lifetime depend on the characteristics of the globular cluster system and it is quite insensitive to the nucleus' initial mass. 
Roberto Capuzzo-Dolcetta (Inst. of Astronomy, University La Sapienza,   Roma, Italy)