Relativistic beaming and orientation effects in core-dominated quasars

In this paper, we investigate the relativistic beaming effects in a well-defined sample of core-dominated quasars using the correlation between the relative prominence of the core with respect to the extended emission (defined as the ratio of the core- to the lobe- flux density measured in the rest frame of the source) and the projected linear size as an indicator of relativistic beaming and source orientation. Based on the orientation-dependent relativistic beaming and unification paradigm for high luminosity sources in which the Fanaroff-Riley class-II radio galaxies form the unbeamed parent population of both the lobe- and coredominated quasars which are expected to lie at successively smaller angles to the line of sight, we find that the flows in the cores of these coredominated quasars are highly relativistic, with optimum bulk Lorentz factor, $\gamma_{opt}\sim6-16$, and also highly anisotropic, with an average viewing angle, $\sim9^0-16^0$. Furthermore, the largest boosting occurs within a critical cone angle of $\approx4^0 - 10^0$. The results suggest that relativistic bulk flow appears to extend to kiloparsec scales in these sources.