Relativistic beaming effect for blazars

In this paper, we revisit the relationship between the spectral index and the core-dominance parameter using a larger sample of 157 blazars (23 BL Lacertae objects and 134 flat spectrum radio quasars), compiled from the available literature. From the relevant data, we find the spectral index associated with the core-dominance parameter, for which a relativistic beaming effect is responsible. In addition, we make a comparison of the properties between BL Lacertae objects and flat spectrum radio quasars.