Optically induced orientation bias in B2 radio quasars

The recent observation that the typical radio of core to lobe flux density at 5 GHz is considerably higher in a sample of B2 quasars selected at 408 MHz compared to the stronger 3CR quasars is shown to be consistent with the ‘unified scheme’ if the optical continuum is also aspect dependent, because that can significantly enhance the probability of making an optical identification in the magnitude-limited B2 sample. The magnitude distributions of strong-core and weak-core sources in the sample provide further evidence that relativistic beam effects in the radio cores are accompanied by an enhancement of the optical continuum radiation.