An application of sphere of activity in three-body model of interacting galaxies (Q1331340)

Gravitational interactions between galaxies have played an important role in the evolution of the observed universe. When a satellite galactic orbit goes deep within the giant centraal galaxy the satellite galaxy will suffer a considerable damage. The peripheral region of the satellite may be stripped by the strong gravitational field of the central galaxy. Many theoretical studies show that the orbits will decay quickly in violently interacting galaxies. The sphere of activity which be considered in the test stars of both central galaxies and satellite galaxies is used in three-body model to study the orbital decay of interacting galaxies. The end product of this decay is a merger of the galaxies involved. In the paper an idealized model considering the sphere of activity of a test star. This means that if both central galaxy and satellite galaxy are located in the sphere of activity of a test star, then the two galaxies and the test star form a general three-body problem. If only one galaxy is located in the sphere then two galaxies and the test star form a semi-restricted tree-body problem. If there is no any galaxy in the sphere, then two galaxies and the test star form a restricted three-body problem. The merger time is accurately calculated and the orbital decay of the satellite galaxy is characterized.