Discordance of the unified scheme with observed properties of quasars and high-excitation galaxies in the 3CRR sample

Abstract

We examine the consistency of the unified scheme of FR II-type radio galaxies and quasars with their observed number and size distributions in the 3CRR sample. We separate the low-excitation galaxies from the high-excitation ones, as the former might not harbor a quasar within and thus may not be partaking in the unified scheme models. In the updated 3CRR sample, at low redshifts (z<0.5), the relative number and luminosity distributions of high-excitation galaxies and quasars do roughly match the expectations from the orientation-based unified scheme model. However, a foreshortening in the observed sizes of quasars, a must in the orientation-based model, is not seen with respect to radio galaxies even when the low-excitation galaxies are excluded. This dashes the hope that the unified scheme might still work if one includes only the high-excitation galaxies.