| Active galactic nuclei(AGN)is the dense region at the center of a galaxy,which has very intense activity phenomena and physical processes.Blazars are the most extreme subclass of AGN,with the relativistic jet direct toward our line of sight.Blazars have two main subclasses,one is flat-spectrum radio quasars(FSRQs),and the other is BL Lacerate objects(BL Lacs).Studying the properties of each subclasses may help us better understand the physical characteristics of blazars.In this thesis,we mainly discuss the statistical analysis of the correlations between the whole sample,the FSRQ only and the BL Lac only,respectively.The first chapter of this thesis introduces the main observed characteristics and classification of the AGN and blazar.The second chapter mainly introduces the spectral energy distribution of blazar jet from the two aspects: the characteristics of broadband energy distribution and blazar sequence.For the blazar sequence,we mainly introduce the observed characteristics ? the theoretical basis and the verification works.The third chapter introduces the radiation mechanisms and models of blazar jet.For the radiation mechanisms,we mainly introduce the radiation process of synchrotron and inverse Compton scattering.In chapter four,we collect a large sample of Fermi blazars with(quasi)simultaneous multi-wave band data.By analyzing the correlations between the peak information ? and the Compton dominance and the spectral index for Fermi blazars,our main results are as follows.(1)One cannot exclude the possibility that the correlations for the whole sample are affected by the difference in distribution of FSRQ and BL Lac in the parametric plane,so the correlation analyze of the two subclasses are necessary.(2)The result may provide an evidence for a fast-cooling emission mechanism for BL Lac.(3)The analysis result of spectral index diagram provides an observational information to the leptonic jet emission model with a log-parabolic shaped electro energy distribution(EED). |
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