Sinking satellites of spiral systems

The interaction of a spiral galaxy with its system of satellites leads to the orbital decay of the satellites on time scales comparable to their orbital periods. Over a Hubble time, the disk of a spiral and the distribution of satellites can be significantly altered by the action of dynamical friction which leads to the exchange of mass and energy between the satellites and the disk. The authors have used a restricted N-body method to uncover the essential dynamics of friction in disk-satellite systems and to investigate the orbital decay rates as a function of the satellite's mass and orbital parameters.