Joint evolution of a galactic nucleus and central massive black hole

The general scheme of the joint evolution of a stellar galactic nucleus and central massive black hole (BH) is deduced in the homology approximation. Physically distinctive stages of this evolution crucially depend on the distribution and motion of stars near the BH which determine the rate of their penetrating into the 'loss-cone' and successive tidal disruption or swallowing by the hole. Joint evolution leads either to contraction or expansion of the stellar cluster around the BH, depending on the parameters of the total system. Respectively, a massive BH in the centre of the host galaxy exists either in the excited state as a powerful central source or in the ground state as a 'dead' quasar. (author)