Study On The Radiative Properties Of The Blazar Jet

Active Galactic Nuclei（AGN）are commonly believed to have a supermassive black hole（SMBH）in the central region of an active galaxies.AGN is a period of galaxy evolution in which changes in SMBH can be directly observed,including high-energy phenomena caused by the relativistic velocity of matter falling into the black hole.The formation of relativistic Jet is related to the structure and radiation mechanism of S MBH,so it is very essential to understand the formation and evolution of AGN for us to understand the black hole and the evolution of galaxy.In the framework of the Unified Model,blazars are Radio-Loud Active Galactic Nuclei that are axially aligned by the observer with the jet.The broad-band spectral energy distributions（SEDs）of blazars cover radio,infrared,optical,ultraviolet,x-ray,andγ-ray,and are exhibited as bimodal structures with two components.Such multi-band simultaneous observations of SEDs are commonly used to study the radiation mechanism of relativistic jets of AGN.The first chapter of this paper briefly introduces the historical background,observation characteristics,structure,and classification of AGN and the unified model.The second chapter briefly introduces the observation characteristics of Blazar,SEDs,classification and Fermi source table,and SEDs introduces the main four bands.Chapter 3 summarizes the broad-band SEDs of blazars,including non-thermal radiation,thermal radiation,and relativistic motion,and finally the main radiation processes.In the four chapter,to verify dominating processes in the inverse Compton mechanism and the origin of soft photons in the dominating processes.We collected multi-wavelength（quasi-）simultaneity data of 75 flat-spectrum radio quasars from the literature.We fitted the spectral energy distribution using logarithmic parabolic functions,then analyzed three correlations for the whole sample,the subsamples of two bins,respectively.The research results are summarized as follows.（1）We find significant correlations of log?_B()_EC?_ext()_syn?and logfor the whole sample and subsamples of two bins,respectively.Our results show that the inverse Compton mechanism of the flat-spectrum radio quasar is preferentially dominant by the external Compton process under the leptonic model.（2）Based on the Bootstrap to calculate observed seed factor distribution,we apply this method to constrain the origin of soft photons of the dominant process of inverse Compton mechanism.The observed seed factor distribution suggests that soft photons are likely to be dominated by dust torus for populations with relatively low synchrotron peak frequencies.But we cannot determine the origin of soft photons of the dominant process of inverse Compton mechanism for populations with relatively high synchrotron peak frequencies.