One of these bodies is combined with an axial magnetic field through a compact object to extract energy in the Blandford-Znajek process. The Eddington limit gives the upper bound for the rate of their formation and, hence, characteristic temperature and the formation of one 
One of these bodies is combined with an axial magnetic field through a compact object to extract energy in the Blandford-Znajek process. The Eddington limit gives the upper bound for the rate of their formation and, hence, characteristic temperature and the formation of one of them around a black hole at the center of a galaxy gives rise to an active galactic nucleus. In cases such as those involving dwarf novae, the gases in these objects behave like highly viscous fluids; these gases are heated by frictional churning as they dissipate angular momentum, a process especially notable in the Roche lobes of certain binary systems. FTP, identify these circular objects formed when material coalesces around a gravitational source.
One of these bodies is combined with an axial magnetic field through a compact object to extract energy in the Blandford-Znajek process.
accretion disk