Studying On The Multi-wavelength Radiation Mechanism And Physical Characteristics Of Fermi Blazars

Blazars are a special subclass of active galactic nuclei(AGN),with many extreme observational characteristics,such as high luminosity,high polarization,rapid variability and apparent superluminal motion.According to the emission line equivalency width(EW),blazars can be divided into BL Lacertae objects(BL Lacs)and flat-spectrum radio quasars(FSRQs).The broad emission lines of FSRQs are swamped by the non-thermal radiation,resulting in some FSRQs being mistaken for low-synchrotron-peaked BL Lac objects(LBLs).Therefore,better classification methods need to be explored.Based on a detailed description of the energy spectrum characteristics and radiation processes of the blazars,this paper conducts an in-depth study of the classification of FSRQs and LBLs.We calculate the γ-ray loudness of the sample sources,and establish the relevant relationship between several physical parameters.Subsequently,we make a distribution of several physical parameters and select several LBLs that are more like FSRQ.The results show that: 1)The synchrotron radiation peak frequency strongly correlates with the γ-ray photon spectral index,γ-ray luminosity,and radio luminosity;2)LBL and FSRQ overlap in many distributions;3)The peak frequency of synchrotron radiation in logarithmic space,the photon spectral index of gamma rays,and the radio flux density at 8.4 GHz in logarithmic space exhibit a distribution similar to a double peak;4)We have calculate Compton dominant for 39 sources,and only two sources have Compton dominant parameters less than 1,proving that some FSRQ may be mistaken for LBL.In addition,we download the full band data of 694 FSRQs and 313 low-peaked BL Lac from Fermi website,and use the log-parabolic modeling(LP)to fit the energy spectrum of these sources.We successfully obtained physical quantities such as the effective spectral index,synchronous radiation peak frequency,and Compton dominant,and analyzed their intrinsic physical characteristics.The following results are obtained:(1)The energy spectrum curvature of both peaks of FSRQ is larger than LBL,the peak frequency of the energy spectrum is distributed in the order of FSRQ<LBL,the distribution range of the Compton dominant of FSRQ is larger than LBL;2)The distribution of the radio band spectral index of the FSRQ is similar to LBL,and the spectral index sizes of the other five bands are distributed according to FSRQ>LBL.The distribution of effective spectral indices from radio to X-ray bands of FSRQ is relatively similar to LBL,while the other effective spectral indices differ significantly;3)There is almost no correlation between the parameters of synchrotron radiation and the energy spectrum parameters of inverse Compton.