Theoretical quasar emissionline ratios. III  Flux divergence and photon escape
Abstract
In this paper we develop a computationally useful version of the probabilistic firstorder differential radiative transfer equation of Frisch and Frisch. This approximate radiative transfer equation is especially appropriate for the evaluation of radiative transfer effects in multilevel atomic systems due to its extreme computational efficiency and reasonably accurate description of the physics of radiation transfer. In particular, it recognizes the distinction between the flux divergence coefficient, ρ, and the photon escape probability, P_{e}. We show that this distinction is crucial for calculations that attempt to construct selfconsistent energy balance models since substitution of P_{e} for ρ in such models leads to large errors (of sign as well as magnitude) in the local cooling rate.
 Publication:

The Astrophysical Journal
 Pub Date:
 August 1981
 DOI:
 10.1086/159131
 Bibcode:
 1981ApJ...248...82C
 Keywords:

 Emission Spectra;
 Line Spectra;
 Photons;
 Quasars;
 Radiative Transfer;
 Cooling;
 Differential Equations;
 Optical Thickness;
 Self Consistent Fields;
 Astrophysics