The Periodicity Analysis of the Light Curve of 3C 279 and Implications for the Precession Jet

Abstract

We have analyzed the light curves of 3C 279 at 22 GHz, 37 GHz, optical R band, and X-ray (2–10 KeV), and found evidence of quasi-periodic outbusts. The light curves show that 3C 279 is an extremely active object. A period of P = 130.6 ± 1.3 days was consistently confirmed by three methods: the power-spectrum method, the discrete correlation function (DCF) method, and the Jurkevich method. Based on the relationship between observed period Pobs and the precession period Pp given by Rieger and our result, the precession period of jet in 3C 279 is Pp ≃ 29.6 yr, which is completely consistent with the precession period of jet of about 30 yr obtained by Carrara et al.. This suggests that there is a precession jet in 3C 279 and the variability period of about 130.6 days that we obtained is most likely caused by the helical motion of the jet.