SUPERPOSITION OF MORGAN AND MORGAN DISKS WITH A SCHWARZSCHILD BLACK-HOLE

The exact superposition of a black hole and a thin disc is considered. The disc is made of counter-rotating particles and belongs to the Mor gan and Morgan family. There are three parameters to play with, the bl ack hole mass, and the disc mass and radius. The superposed exact solu tion comprehends several configurations, some yield mass ratios in con formity with the usual accretion discs. There is also a remarkable con figuration of a black hole surrounded by a disc made of pure superlumi nal matter up to the edge, which is at the photonic orbit.