Dynamical friction on Globular Clusters in core-triaxial galaxies: is it a cause of massive black hole accretion?

Abstract

The present work extends and deepens previous examinations of the evolution of globular cluster orbits in elliptical galaxies, by means of numerical integrations of a wide set of orbits in 5 self-consistent triaxial galactic models characterized by a central core and different axial ratios. These models constitute a valid and complete representation of regular orbits in elliptical galaxies. Dynamical friction is definitely shown to be an efficient cause of evolution for the globular cluster systems in elliptical galaxies of any mass and axial ratios. Moreover, our statistically significant sample of computed orbits confirm that the globular cluster orbital decay times are, in a wide range of realistic initial conditions, much shorter than the age of the galaxies. Consequently, the huge quantity of mass carried into the innermost galactic region in form of decayed globular clusters have likely contributed significantly in feeding and accreting a compact object therein.