The effect of suprathermal protons on the physical conditions in Seyfert galaxy nuclei. II

The radiative transfer of Lα, Lβ, and Hα in a hydrogen gas containing dust is considered with application to the emitting gas in Seyfert galaxies. The line radiation originates from the kinetic energy of suprathermal particles, lost initially to a free electron gas, which then delivers it to the radiation through excitation of neutral hydrogen atoms. By neglecting the direct escape of line radiation and by averaging over the gas, we suppress the transfer in space and consider transfer in frequency only. The dust degrades the line radiation via frequency-independent absorption, converting the energy to infrared luminosity. We solve for the source functions in the lines, using appropriate approximations, in order to determine under what conditions the narrow component of the Balmer line radiation from the gas can be self-absorbed and degraded without similar degradation of the broad component, which originates from the suprathermals themselves. The results of the transfer calculation are used to find self-consistent values for the temperature and ionization of the gas for various amounts of dust and various concentrations of suprathermal particles. Finally, we examine the luminosity in the Balmer continuum that would result under these conditions