Study On Multi-band Flux Correlation And Quasi-periodic Variability Of The Blazar

Blazar is one of the rarest active galactic nuclei(AGN)and one of the most active objects.The study of the light variability of blazar can explore the internal radiation process and the physical mechanism of the blazar.Therefore,the study of the light variability of a blazar is of great significance to understand AGNs.Moreover,the current ground telescope and space telescope have realized the full band observation of objects,which makes the study of light variation feasible.The main content of this paper is to search the multi-band quasi-period of objects by using the standard quasi-period detection technology and to study the correlation between optical and gamma-ray in TEV objects.Our first work is to analyze the light variation of CGRa BS J0835+6835.Firstly,we get the observation data from the 40-meter telescope of the Owens Valley Radio Observatory(OVRO)and simply evaluate its activity.Secondly,we use the Lomb-Scargle periodogram(LSP)and the weighted wavelet z-transform(WWZ)to detect the quasi-period.Results we detected a quasi-periodic oscillation(QPO)of about 560 days in the mutant CGRa BS J 0835+6835.The spiral jet model in the supermassive binary black hole system may be the cause of its quasi-periodic oscillation,so we use this model to estimate the mass m of its primary black hole to be about 3.5 x 10~9M_⊙.To explore whether there is the beaming effect in this source,we use the double exponential function to fit six burst processes and find that the average value of optical Doppler factorδ_Vis about 10.76,which indicates that there is an obvious beaming effect in the radio radiation of this source.Our second work is to analyze the multi-band light variability of BL Lac 4FGL J0112.1+2245.First,the light variability data of 15 GHz radio,optical,and 0.1-300Ge V gamma-ray bands were obtained from OVRO,Catalina Real-time Transient Survey(CRTS),and Fermi gamma-ray space telescope,respectively.Secondly,the standard LSP and WWZ techniques are also used to detect the quasi period.Results a possible quasi period of 876 days was detected in all three bands.Assuming that the QPO originated from the spiral jet in a merging supermassive binary black hole system,we estimated the mass M～2.2×10~9M_⊙.We also use the discrete correlation function(DCF)to analyze the correlation between the multi-bands and find that there is a strong correlation between the gamma-ray and the optical band,and this result is not consistent with the previous researchers’results,especially the data in the past three years show that the light changes of the three bands are almost consistent,which means that the radiation area or radiation area of the three bands at some time the mechanism may be consistent.Our third research work is to explore the correlation between gamma-ray and optical band in TEV blazar.The two band data of 54 sources are collected,and the DCF method is used to calculate the correlation strength of the two bands.Finally,22sources are found to have a strong correlation.Synchrotron self-Compton(SSC)model can well explain the strong correlation,while the weak correlation can be explained by"Orphan"flare.The time delay between the two bands ranges from 0 to 2.6 years.