Long-time Observations Of Blazar 3C 273 With SMA

In this thesis, we introduced the general properties, the classification and vari-ability of AGNs and subclass blazars. By means of the the power spectrum analysis and autocorrelation DCF analysis, we study the variability timescale of the classical blazar 3C 273 at 230 GHz & 345 GHz radio band nearly 10 years with the Sub-millimeter Array (SMA) telescope observations. Our results show that the variability timescale of 3C 273 is rather evident:at 230 GHz, the variability timescales of 327.87 days exist; at 345 GHz, the timescale of 276.2 days exist. Then we analysis the cross correlations between our light curves 230 GHz and 43 GHz, which light curves come from literatures, using the discrete correlation function (DCF) method. The cross correlation results suggest that there are evident radio-radio correlations, the high-er frequency variation would lead that lower frequency. Finally, we use the same method to study the correlation between 230 GHz and γ-ray band. The result shows 230 GHz variations following the γ-ray band, which place further constraints on the localization of the γ-ray production zone in parsec-scale jets.