Relativistic Beaming and Orientation Effects in Lobe-Dominated Quasars

Abstract

We examine a simple statistical consequence of relativistic beaming model using the core-to-lobe flux density ratio (R) and projected linear size (D) as orientation indicators. It is shown that the observed R-D intercept for the 3CRR source sample provides values of the bulk Lorentz factor (γ) which are consistent with the beaming scenario. The result also shows that if the lobe-dominated quasars are to be unified with the core-dominated quasars, they should be oriented at a median angle, φ_med ∼ 40° with respect to the line of sight, but if with powerful radio galaxies, then φ_med ≈ 24°. Application of this result to the quasar-galaxy unification scheme using the observed angular size-redshift relation shows that the scheme is consistent with the observed data.