The Multi-wavelength Emission Of Blazars3C66A

In this thesis, general characteristics of active galactic nuclei(AGN) and its subclass blazars are briefly reviewed, including the definitions, classification, uni-fied model of AGN, properties of spectral energy distribution (SED) and sequence of blazars. Three emission models of muti-wavelength SEDs corrected by extra-galactic background light(EBL) are calculated. The simultaneous SEDs of3C66A from September1to December31in2008were fitted by three models.The results are as follow. The low-energy component of SED of3C66A is explained well by synchrotron emission from relativistic electrons in jet. The high-energy component of SED, the TeV spectra of3C66A is very hard after corrected by EBL for the redshift of0.444. This result challenges the traditional SSC model, which may indicate that the hard intrinsic γ-ray spectrum can be explained by hadronic model. Two hadronic models were used to explain the SED:(1) Synchrotron radiation of proton model, in this model, the hard intrinsic TeV spectrum is dominated by interaction of high energy photon produced by Synchrotron radiation of proton with emission line photon in broad line region.(2) SSC+Pγ model, the TeV emission is dominated by decay of neutral pion produced through proton-photon interaction. Two models can both explain the SED of3C66A well, large magnetic field about50G is required in model (1), and the emission region is located within BLR. While, the model (2) requires very large proton power to produce the γ-ray through proton-photon interactions efficiently.