The Variability Analysis Of Hard X-ray And Gamma-ray Light Curves Of Active Galactic Nuclei

The Active Galaxy Nuclei(AGNs)has a very complex light curve,which reflects the radiation mechanism and process of this kind of celestial body in some extent.Our paper mainly analyzes the hard X-ray light curves of various AGNs and the gamma-ray light curves of blazars.The thesis first introduces the basic characteristics,productivity mechanism,unified model and classification of AGNs and the observation of AGNs in the gamma-ray band.Then introduces the observation characteristics,standard physical models,light curve properties,energy spectral characteristics and evolution sequences,radiation models of blazars and comparison of the two radiation models,correlations and differences of subclasses of blazars,and the properties of Fermi blazars.Subsequently,we introduce the light curve properties of the AGNs,time scale of variability,light curve classification and variability model,power spectrum of AGNs,Variability of hard X-ray light curve,definition and calculation of RMS,relationship between RMS of light curve and photon flux.The hard X-rays may come from the inner of accretion disk and the thermal corona,or from the jet.The different origins cause hard X-ray light to exhibit different characteristics.Based on the light curve data of the AGNs in the hard X-ray band observed by Swift / BAT,we mainly analyzed the distribution difference of the power law index of the power spectrum of the hard X-ray light curves of AGNs.Through the fast Fourier transform method,the power spectrum of various kind of AGNs are obtained,and the distribution characteristics of its power law index are analyzed.It was found that the power law index distribution of Seyfert 2 and the type 1 AGNs is significantly different,while the difference between the subclasses of type I AGNs is not significant,and the hard X-ray of Seyfert 2 may come from the inner accretion disk and the hot crown.The hard X-rays of the Seyfert 1 mainly come from the outflowing corona.Our results show that the power law index of hard X-rays from relativistic jets or outflow coronas is statistically larger than that of hard X-raysfrom accretion disk thermal coronas.Based on the data released by the third catalogue of Fermi satellites,we selected 235 clean blazars that were less affected by the surrounding gamma-ray bright and extended sources.For the variability of the gamma ray light curves,we mainly study the relationship between the gamma-ray RMS of the Fermi blazars and the gamma-ray flux,and the distribution characteristics of the flux.We performed the correlation analysis of RMS and the flux of 100Mev-200 Gev gamma-ray light curves in the sample,and the lognormal fitting of the flow distribution.Based on the three parameters of linear fitting slope,Pearson coefficient,and the width of the lognormal distribution,the properties of two subcategories of blazars,FSRQs and BL Lacs,were statistically analyzed.The results show that the statistical average values of the three parameters of FSRQs are all greater than BL Lac,which means that flux of FSRQs changes more rapidly than BL Lac in the high-energy band with increasing flux.Based on this property,we have judged that an unknown type of blazar may belong to FSRQs.