No CrossRef data available.
Published online by Cambridge University Press: 12 April 2016
High-excitation extended emission-line nebulae around active galactic nuclei probably result either from photoionization of the interstellar medium by beamed continuum radiation, or dynamical interactions between radio sources and the ambient gas, or both. Here I discuss the models based on these mechanisms, and their relative importance in radio-quiet and radio-loud active galaxies.