Radiation pressure in spectral lines in a medium with supersonic axisymmetric motions. II - Gas-dust systems with local radiative coupling

It is shown that the radiation pressure exerted by radiation in resonance lines on dust particles or free electrons in a medium with supersonic axisymmetric motions is the most effective mechanism for transferring angular momentum from the radiation to matter (calculated for unit radiation density). The efficiency of this process depends on the optical thickness of the dust system and is maximal when the dust system optical thickness is about 1. In optically thin systems, the tangential pressure on the dust always coincides with the direction of rotation of the system. Criteria are obtained for the effectiveness of radiation pressure, and the part which it plays in generating angular momentum under the conditions of the nuclei of active galaxies and quasars is considered