The Vertical Structure and Ultraviolet Spectrum of X‐Ray–irradiated Accretion Disks in Active Galactic Nuclei

Motivated by recent work indicating that the UV continuum in AGN may beproduced by reradiation of energy absorbed from X-rays irradiating an accretiondisk, we present a calculation of the vertical structures and ultravioletspectra of X-ray irradiated accretion disks around massive non-rotating blackholes. After finding the radial dependence of vertically-integrated quantitiesfor these disks, we solve the equations of hydrostatic equilibrium, energybalance, and frequency-dependent radiation transfer as functions of altitude.To solve the last set of equations, we use a variable Eddington factor method.We include electron scattering, free-free, and HI, HeI, and HeII bound-freeopacities and the corresponding continuum cooling processes. While the overall spectral shape predicted by X-ray irradiation may becompatible with observations, the Lyman edge emission feature it predicts isnot. This finding raises questions for many otherwise plausible models in whichX-ray irradiation plays a major role.Comment: 43 pages, 10 figure