Analysis Of Optical Variability And Color Index Of Blazar

Active galactic nuclei(AGNs)which contains Blazars that play an important role are one of the most special planet.Variability whose being researched can reflect the physical characteristics of Blazars is a vital phenomenon of Blazars.Therefore,it is helpful to study variability of Blazars for knowing more about Blazars and AGNs and knowing more information of this kind planet which is an essential part.There are four chapters in total in this passage.In first chapter,some simple introduction of basic and multi-wave band flux characteristics of Blazars will be done.As for the second chapter,I will do some introduction of variability time,the sort and the physical model of variability time.Besides,I will make an introduction of some accurate ways to work out variability time in the third chapter,such as The Jurkevich method,the structure function,the power spectral density method,the wavelet method,the discrete correlation function method[1].In this chapter,I also collect some data of PKS 0537-441 among the infrared and optical bands,then,using The Jurkevich method and The power-spectrum method,analyze the variability time of these data to find out that the variability time of PKS 0537-441 is 1038 days and 583 days.If the variability time is related to accretion disk,we will get the result that the radius of unstable region is 9.0×1014(88).However,the radiation radius of the area 4.33×1014(88)to get this result with Bing-Kai Zhang et al in 2013 exactly the same.It is shown that the variability analysis of PKS 0537-441 is probably due to the instability of the accretion disk.At last,using the discrete correlation function method,the correlation analysis of these band,showing that there is a good relativity,and that there is a strong relativity between optical band and infrared band,but there is time lag,which suggests that their process of radiation is same but the district of radiation is different.In the fourth chapter,I collect 37 multi-band data of Blazars,and analyze their color index,finding that BL lac turns blue when it gets brighter,while FSRQs can turn blue and red.Then discuss the physical model of these phenomena and get the result that it is caused by shock-in-jet model.