Dynamical Friction in Cuspidal Galaxies
  Dynamical friction is the process responsible for matter transport toward the
inner regions of galaxies in form of massive objects, like intermediate mass
black holes, globular clusters and small satellite galaxies. While very bright
galaxies show an almost flat luminosity profile in the inner region, fainter
ones have, usually, a peaked, cuspidal, profile toward the center. This makes
unreliable, in these cases, the use of the classic Chandrasekhar's formula for
dynamical friction in its local approximation. Using both N-body simulations
and a semi analytical approach, we have obtained reliable results for the
orbital decay of massive objects in cuspidal galaxies. A relevant result is
that of a shallower dependence of dynamical friction braking on the satellite
mass than in the usual Chandrasekhar's local expression, at least in a range of
large satellite masses.
