PL和LP谱型费米耀变体的伽马射线辐射参量统计研究

Statistical Research on the Parameters of Gamma-ray Radiation of PL and LP Fermi Blazars

从Fermi-LAT第四期AGN目录中,收集1462个高置信度费米耀变体,研究MeV-GeV伽马射线能段对数抛物线(Log-Parabolic,LP)和幂律(Power-Law,PL)谱型耀变体的红移和能流、光度、光变指数的分布差异.结果显示:LP谱型耀变体的能流、光度、光变指数比PL谱型高;两种谱型耀变体能流、光度、光变指数呈双峰分布,而红移遵循单峰分布;与Fermi-LAT第三期统计结果相比,两种谱型在光度分布上不再是单峰分布,这可能与长期观测光子数的累积有关.两种耀变体在光度分布上的不同,间接地反映内禀光度是可区分的,或吸积盘等一些本征参数可能是可区分的;同时耀变体的能流、光变指数、光度三个参量都呈现双峰分布,暗示LP和PL谱型是本征的,可能与喷流内部实际的物理过程和辐射机制有关.

1462 high confidence Fermi blazars were collected from the fourth catalog of active galactic nuclei detected by the Fermi Large Area Telescope(4LAC),then the distribution of energy flux,redshift,variability index,and luminosity for the MeV-GeV Log-Parabolic(LP)and Power-Law(PL)blazars were compared.As a conclusion:the LP blazars showed higher energy flux,variability index,and luminosity than the PL blazars′s.The energy flux,variability index,and luminosity of LP and PL blazars were bimodal distribution,while the redshift followed unimodal distribution.Compared with the third catalog of active galactic nuclei detected by the Fermi Large Area Telescope(3LAC),the luminosity no longer presented unimodal distribution,which is caused by the cumulative photons.The difference of luminosity distribution also reflected that the intrinsic luminosity was distinguishable.What′s more,the three parameters of blazars showed obviously bimodal distribution,which confirmed that LP and PL spectral were intrinsic and may related to the actual physical processes and radiation mechanisms of the jet.