2022PASP..134f4101Z

For blazars, its radio emissions are composed of two components. In the high energy bands, Tera-electronvolts (TeV; 10¹²electronvolts) emissions were detected from some blazars. Does the TeV emission also consist of two components? To investigate the TeV emission component, we compiled a sample of 51 TeV blazars with available radio core dominance parameters and applied a two-component (the beamed and the unbeamed) model to study the composition of blazar TeV emission. We obtained the core-dominance parameter at the TeV band through applying a relativistic beaming model, and found that the average TeV core-dominance parameter is log R_TeV^L=<3.12 ±2.83 >for 46 BL Lacs, and that is log R_TeV^FSRQ= <4.80 ±1.76 > for 5 FSRQs, which shows an indication that the core dominance parameter in BL Lacs is smaller than that in FSRQs. For the three subclasses of BL Lacs-high synchrotron peaked BL Lacs(HBLs), intermediate synchrotron peaked BL Lacs(IBLs) and low synchrotron peaked(LBLs), log R_TeV^HBL is smaller than log R_TeV^IBL and log R_TeV^LBL. Our results suggest that the blazar TeV emission from the core is thousands times stronger than from the extended region and the TeV emission is more core-dominated for the lower synchrotron peaked sources. In addition, a significant correlation between the TeV core-dominance parameter (log R_TeV) and the radio one log R_radio) log R_TeV = (2.56 ±0.08) log R_radio + 0.99, is obtained suggesting that the TeV emission is beamed and the TeV core-dominance parameter is an indicator of beaming effect at the TeV bands, and that the TeV emission has stronger beaming effect than the radio emission.