THE VERTICAL STRUCTURE AND RADIATION-FIELDS OF ACCRETION DISKS IN THECENTERS OF AGNS

We describe the construction and main properties of stationary accreti on discs that are supposed to produce the high luminosities of Active Galactic Nuclei. It is found that for most parameter combinations the discs are geometrically thin everywhere. However, for high accretion r ates and/or low local energy generation rates they may get thick close to the central object. The distributions of the temperature, the gas pressure and the vertical optical depth are characterized by steep gra dients close to the surface and very flat stratifications in the inner parts. The ratio of the radiation pressure to the gas pressure varies over several orders of magnitude within a disc. The emergent fluxes c an be well approximated by power laws in a wide wavelength range but t um over in the middle or extreme UV range. It is argued that this rang e is best suited for spectral diagnosis from the continuum.