Physical Sience and Technical Research

With the construction and running of sky-bone and ground-based telescopes at various frequencies, particularly for the launch successfully and the running steadily, nearly making the observations from radio up to high-energy γ-rays come true, this largely promotes the development of research in active galactic nuclei (AGN). This paper summarizes the current advances in theoretical and observations focusing mainly on the blazar, one of the subclass of the AGN, we begin with the united scheme of the blazar, and present the constituents, the structure and the photon distribution of the external radiation fields, together with the multifrequency observations, we also demonstrate the great achievement since the running of the Large Area telescope (Fermi/LAT) on Fermi Gamma-ray Space Telescope mission. Finally, we present some basic questions, which remains exist in the research of the blazar.

Active Galactic Nuclei, Blazar, BL Lac objects, Flat Spectrum Radio Quasars, Multifrequency Observations