The emission spectrum of active galactic nuclei. I - Computational methods

A program built for studying photoionized models of broad line emitting clouds in active galactic nuclei is described. A review of the most recent models is given, and the program described within is specially designed to study clouds of a high column density (greater than about 10 to the 23rd/sq cm). It is shown that the destruction of line photons by continuum processes can be approximated well by the local escape formalism if special precautions are taken. Attention is also drawn to the necessity of computing correctly the transfer of diffuse continua (Balmer, Paschen, etc.) if their optical thickness at the edge approaches unity.