Jin Zhang, Xiao-Na Sun, En-Wei Liang, Rui-Jing Lu, Ye Lu, Shuang-Nan Zhang
We present SEDs fits to a sample of GeV-TeV FSRQs and compare the jet properties between FSRQs and BL Lacs. We show that the SEDs can be fit with the leptonic model, and both the minimum and broken Lorentz factors of relativistic electrons are well constrained, with medians of 48 and 240, respectively. No statistical difference on the Doppler factors between the FSRQs and BL Lacs is found. Assuming that the jet power is carried by electron-proton pairs, the magnetic field, and radiation field, we calculate the powers of these components and the total jet power based on our fitting results, hence derive the radiation efficiency and magnetization parameter of the jets. It is found that the FSRQ jets are dominated by the Poynting flux and have a high radiation efficiency, whereas the BL Lac jets are dominated by particles and have a lower radiation efficiency than FSRQs. Interestingly, different from BL Lacs, jet powers of FSRQs are proportional to their central black hole masses, favoring the scenario that the FSRQ jets are powered by the BZ mechanism. The jet production rate per central BH mass of FSRQs seems to be universal among these sources, whereas it varies over five orders of magnitude for BL Lacs. These results likely suggest that the dominating jet production mechanisms may be different for FSRQs and BL Lacs; the BZ process for FSRQs, the BP and/or BZ processes for BL Lacs, depending on structures and accretion rates of accretion disks. Jet power is correlated with the cavity kinetic power for our blazar sample. The magnetic field energy in the jets may provide the cavity kinetic energy for FSRQs and the kinetic energy of cold protons in the jets may be crucial for cavity kinetic energy for BL Lacs.
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http://arxiv.org/abs/1307.6911
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