Search

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 BL = 〈 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 Lacsâ€"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. [ABSTRACT FROM AUTHOR]

The origin of jets is one of the most important issues concerning active galactic nuclei, yet it has remained obscure. In this work, we made use of information from emission lines, spectral energy distributions, and Fermiâ€"LAT Îł -ray emission to construct a blazar sample that contains 667 sources. We note that jet power originations are different for BL Lacertae objects (BL Lacs) and flat-spectrum radio quasars (FSRQs). The correlation between jet power P jet and the normalized disk luminosity L Disk/ L Edd shows a slope of âˆ'1.77 for BL Lacs and a slope of 1.16 for FSRQs. The results seem to suggest that BL Lac jets are powered by extracting black hole (BH) rotation energy, while FSRQ jets are mostly powered by accretion disks. Meanwhile, we find the accretion ratio M ̇ / M ̇ Edd increases with the normalized Îł -ray luminosity. Based on this, we propose a dividing line, log (L BLR / L Edd) = 0.25 log (L Îł / L Edd) âˆ' 2.23 , to separate FSRQs and BL Lacs in the diagram of L BLR/ L Edd against L Îł / L Edd using a machine-learning method; the method gives an accuracy of 84.5%. In addition, we propose an empirical formula, M BH / M ☉ ≃ L Îł 0.65 / 21.46 , to estimate BH mass based on a strong correlation between Îł -ray luminosity and BH mass. Strong Îł -ray emission is typical in blazars, and the emission is always boosted by a Doppler-beaming effect. In this work, we generate a new method to estimate a lower limit of Doppler factor δ and give δ BL Lac = 7.94 and δ FSRQ = 11.55. [ABSTRACT FROM AUTHOR]