Recently, the Canadian Hydrogen Intensity Mapping Experiment detected periodicity in the bursting rate of the repeating FRB 180916.J0158+65. In a popular class of models, the fast radio bursts (FRBs) are created by magnetic flares of a hyperactive magnetar driven by fast ambipolar diffusion in the core. We point out that in this scenario the magnetar is expected to precess freely with a period of weeks to months. The internal magnetic field B ∼ 10 16 G deforms the star, and magnetic flares induce sudden changes in magnetic stresses. The resulting torques and displacements of the principal axes of inertia are capable of pumping a significant amplitude of precession. The anisotropy of the flaring FRB activity, combined with precession, implies a strong periodic modulation of the visible bursting rate. The ultrastrong field invoked in the magnetar model provides: (1) energy for the frequent giant flares, (2) the high rate of ambipolar diffusion, releasing the magne...

中文翻译：

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进动的扩频电磁作为重复FRB 180916.J0158 + 65的来源

最近，加拿大氢强度测绘实验检测到重复的FRB 180916.J0158 + 65的爆裂速率具有周期性。在流行的一类模型中，快速无线电脉冲串（FRB）是由磁芯中快速双极性扩散驱动的超活性磁星的磁弹产生的。我们指出，在这种情况下，预计磁星将在数周至数月的时间内自由进动。内部磁场B〜10 16 G使恒星变形，而磁弹会引起磁力的突然变化。所产生的扭矩和惯性主轴的位移能够泵出很大的进动幅度。燃烧的FRB活性的各向异性与进动相结合，意味着可见爆发速率的强烈周期性调制。