On the 15GHz Radio Variability of Flat-spectrum Radio Quasar B3 0307+380

The long-term monitoring data of Owens Valley Radio Observatory (OVRO) show that FSRQ B3 0307+380 has many flares in the 15GHz light curve. Based on the double exponential form function, we have fit twelve flares, then derived the variability amplitude, the rise and decay time scales of each flare, and evaluated the brightness temperature (T_b) and variability Doppler factor (δ_V). The range of δ_V is from 9.12±0.58(sd) to 35.38±3.34(sd), with the average of 18.65±7.11(sd). This result indicates that the radio emission is strongly beamed, and it is consistent with the well-known relativistic jet model. Making use of LSP and WWZ methods, we examined if there is a period in the radio light curve of B3 0307+380. As a result, we find a period of about 244 days with a confidence level of > 99%, and give the possible explanation about this period.