1998A&A...333..790Q

We study the correlations between the core dominance parameter R and the core and extended powers P_core and P_ext in the case of quasars with four different samples. In some samples, logP_ext is highly anti-correlated with logR while logP_core is not at all correlated with logR. This effect seems to be common in the case of quasars when R is not very small. It obviously contradicts the conventional hypothesis of the core and extended emissions of radio sources in accordance with unified schemes and beaming models. Our study also implies that when R becomes larger, the anti-correlation between logP_ext and logR becomes more obvious while the correlation between logP_core and logR becomes less obvious; when R becomes smaller, the above anti-correlation becomes less obvious while the correlation becomes more obvious. This effect can be interpreted by assuming that, for the lobe-dominated quasars, the emission of the core is beamed and oriented, while for core-dominated quasars, the emission of the core is unbeamed and isotropic.