| 其他摘要 | Active Galactic Nuclei (AGN) are characterized by the peculiar observational phenomenon and have been one of the hottest areas of astrophysical research for half a century. Investigating the properties of AGN can shed light on the environment surrounding the center massive black hole and help us understand the co-evolution between the center massive black hole and the host galaxy，which is the hint of the evolution of the universe. Jet is the common phenomenon in the universe. They can be found through the small solar corona jet to the large scale jet in AGN. Based on the extreme physical condition, researching the astronomical jet can help to investigate the existed physical models and explore the unknown physical mechanisms. Jets are thought to be likely related to the accretion process of the center compact object and are the bridge between the center compact object and the external interstellar medium. This thesis mainly focuses the jet in the AGN and contains two parts. The first part is focusing on introduction of the background of the research of the jet in AGN. In the first section, I describe the basic properties of the AGN, including the observational characters and theoretical models. Then I introduce astronomical jets in different types of celestial bodies。In the second section, the radio loud AGNs classification which is based on the observational characters in different wavelengths and the SED properties is described. Since the relativistic jet model is widely accepted, I list several evidences of the relativistic jet model by comparing with the observational phenomena. Then, the classic jet radiation model, single zone homogeneous leptonic model, is briefly introduced. I discuss the observational constraints to the radiation model parameters. The hadronic model is simply mentioned and compared with the leptonic model. The challenges for the research of the jet in AGN is introduced in Section 2.4. In the end of the second section, the research progress of the jet in AGN at the $Fermi$ era is specially introduced. Firstly, the main results of the $Fermi$/LAT observation are presented. Then the radio, optical, X-ray and VHE $\gamma$-ray instruments and research results are given. Then the progress of multi-wavelength observation on different class of Blazars are presented. In the third section, I introduce the operation principle, the basic properties and the data reduction process of the $Fermi$/LAT. In the second part of the thesis, three research works are presented. In the first work, we present the detailed analysis and results of long term simultaneous observations in the radio, near-infrared, optical, X-ray and $\gamma$-ray bands, together with our own photometric observations for S5~0716+714. Its multi-wavelength variability properties can be naturally explained by the classic leptonic blazar radiation models. The orphan $\gamma$-ray flare which strongly supports the hadronic models is not detected. Electrons probably play an important role in the energy dissipation of Blazars. Furthermore, different leptonic radiation models are distinguished. The pure SSC model is ruled out, while the external soft photons such as the broad line region or the hot dust emission, is needed to explain the $\gamma$-ray emission of S5~0716+714. The intensity of the external soft photon fields may exhibit a evolution behavior through different types of Blazars. In the our second study, we report a detailed analysis of $\gamma$-ray data of 2FGL J0509.9+1802, especially focusing on April 2013 when extraordinary $\gamma$-ray variability has been detected. The $\gamma$-ray emission of PKS 0507+17 is identified at the first time. The daily peak flux is over two orders of magnitude higher than the two-year average flux. Rapid $\gamma$-ray variability with doubling time of 2-3 hours has been detected, indicating a location of $\gamma$-ray emission inside the broad line region. Together with the bluer-when-brighter $\gamma$-ray spectr |
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