Ratio of the Core to the Extended Emissions in the Comoving Frame for Blazars

In a two-component jet model, the emissions are the sum of the core and extended emissions: S^ob=S_core^ob+S_ext^ob , with the core emissions, S_core^ob= f S_ext^obδ ^q being a function of the Doppler factor δ , the extended emission S_ext^ob , the jet type dependent factor q , and the ratio of the core to the extended emissions in the comoving frame, f . The f is an unobservable but important parameter. Following our previous work, we collect 65 blazars with available Doppler factor δ , superluminal velocity β _app , and core-dominance parameter, R , and calculated the ratio, f , and performed statistical analyses. We found that the ratio, f , in BL Lacs is on average larger than that in FSRQs. We suggest that the difference of the ratio f between FSRQs and BL Lacs is one of the possible reasons that cause the difference of other observed properties between them. We also find some significant correlations between log f and other parameters, including intrinsic (de-beamed) peak frequency, logν _p^in , intrinsic polarization, log P^in , and core-dominance parameter, log R , for the whole sample. In addition, we show that the ratio, f , can be estimated by R .