ACTIVE GALACTIC NUCLEI .5. X-RAY VARIABILITY AND THE BLACK-HOLE CLUSTER PARADIGM

A random superposition of elementary luminosity bursts of rectangular or triangular shape produces X-ray luminosity flicker curves character ized by features corresponding to those observed in the X-ray-variable Seyfert galaxies and other active galactic nuclei. Such luminosity ev ents could be produced by accretion processes resulting from tidal dis ruption and consumption of stars by small (approximately 1 M.) black h oles, or much more frequently from such holes passing and disrupting a ccretion disks belonging to large holes in a nuclear cluster.