Theoretical quasar emission-line ratios. VII - Energy-balance models for finite hydrogen slabs

Abstract

The authors present energy-balance calculations for finite, isobaric, hydrogen-slab quasar emission-line clouds which incorporate probabilistic radiative transfer (RT) in all lines and bound-free continua of a five-level plus continuum model hydrogen atom. They discuss the resulting line ratios, regions of line formation, level populations, and range of applicability of the models. The calculations neglect the effects of heavy elements and secondary ionizations from primary photoelectrons. An appendix presents a detailed comparison of differences between four different methods of treating the radiative transfer: (1) the probabilistic method, (2) an exact RT solution, (3) an effective two-level ρ = p<SUB>e</SUB> energy-balance calulation, and (4) a ρ = p<SUB>e</SUB> calculation explicitly incorporating indirect photon creation and destruction paths.