An investigation of the rapidly cooling ring in an accretion disc around a black hole

The rapidly cooling ring in an accretion disc around a black hole is investigated in further detail by numerically integrating a system of hydrodynamic equations. Calculations are performed for a 10 solar masses black hole and for four cases with different parameters. The existence of a gravitational collapse region is revealed. A possible detection is suggested to prove the occurrence of such a ring. (author)