The Receding Torus Model—evidence from emission-line luminosities and the quasar fraction

Abstract

Evidence for the Receding Torus Model for radio-loud AGN comes from two main sources: (i) the rise in quasar fraction with emission-line luminosity; and (ii) the difference in emission-line luminosity between radio galaxies and radio quasars. We have constructed a new type of luminosity function which shows that a two-population model, with a low-luminosity population of radio galaxies and a high-luminosity population composed of radio galaxies and radio quasars, can mimic the effects of a receding torus. The data are best explained, however, by a two-population model with a receding torus in both populations.