The interacting subsystems theory of active galactic nuclei - I. The broad-absorption-line QSO theory

The theory of broad-absorption-line (BAL) QSOs is worked out on the basis o f the radiation hydrodynamics equation solution for the two-phase media of active galactic nuclei. We suppose that the BAL QSO physics depends on some 'hidden' AGN parameters, such as the mass and size of the compact stellar system. We therefore approach this problem in the more general framework of the 'interacting subsystems theory', which includes these parameters. We c ompare the results of the numerical model calculations with the observed sp ectra and show that the BAL QSOs (and the radio-quiet quasars as well) cont ain massive compact stellar kernels in their central regions. We show that the line-locking effect is determined by the radiation pressure, and is als o favoured by the drag force of the hot gas acting on the line-absorbing cl ouds. We derive some general conclusions about the physics of AGN. In particular, we show that the radio-quiet versus radio-loud dichotomy fan be explained by using two types of hot gas outstreams in quasars.