Hydrogen photoionization dominates the momentum transfer by ultraviolet radiation to gas clouds in the emission-line region of quasi-stellar objects and Seyfert nuclei. For radiative acceleration to the observed velocities, the gas clouds must be in pressure equilibrium with the ambient medium and have masses <10-8 o. Constraints on the nature of the intercloud medium and the effects of differential radiative forces are discussed. The radiative acceleration of fully ionized clouds is proportional to the gas density, which may explain why permitted spectral lines are often broader than forbidden lines. Subject headings: nebulae - quasi-stellar sources or objects - Seyfert galaxies
No takes yet. Share an insight, caveat, or question.
William G. Mathews (1974) studied this question.