5.3.4 Host Galaxies A simple test of unification is that the
morphology and magnitude of radio galaxies and quasar host
galaxies be comparable. At present the observational situation
for quasars and FR II radio galaxies is not entirely clear, as
comparisons of their mean host galaxy luminosities have led to
conflicting conclusions. Some studies have found radio galaxies
to be fainter by ~ 0.5-1 magnitude (Hutchings 1987; Smith and
Heckman 1989), while others concluded the mean magnitudes (and
dispersions) were comparable (Véron-Cetty and Woltjer 1990;
Lehnert et al. 1992). In part, determining quasar host galaxy
magnitudes is difficult, and in part the differences between the
conflicting results may be explained by systematic effects
(Abraham et al. 1992) and/or by incomplete or heterogeneous
samples. For example, in the present unification scheme the
parent population consists of luminous narrow-line radio
galaxies, yet samples of ``powerful radio galaxies'' used to
test unification sometimes include broad-l