Polarization and variations of BL Lacertae objects

BL Lacertae objects are an extreme subclass of AGNs showing rapid and large -amplitude variability high and variable polarization, and core-dominated r adio emissions. IF a strong beaming effect is the cause of the extreme: obs ervation properties! one would expect that these properties would be correl ated with each other. Based on the relativistic beaming model, relationship s between the polarization and the magnitude variation in brightness, as we ll as the core-dominance parameter are derived and used statistically to co mpare with the observational data of a BL Lacertae object sample. The stati stical results are consistent with these correlations, which suggests that the polarization, the variation, and the core-dominance parameter are possi ble indications of the beaming effect.