Fast radio bursts (FRBs) are bright, millisecond-duration radio transients originating from sources at extragalactic distances1, the origin of which is unknown. Some FRB sources emit repeat bursts, ruling out cataclysmic origins for those events2–4. Despite searches for periodicity in repeat burst arrival times on timescales from milliseconds to many days2,5–7, these bursts have hitherto been observed to appear sporadically and—although clustered8—without a regular pattern. Here we report observations of a 16.35 ± 0.15 day periodicity (or possibly a higher-frequency alias of that periodicity) from the repeating FRB 180916.J0158+65 detected by the Canadian Hydrogen Intensity Mapping Experiment Fast Radio Burst Project4,9. In 38 bursts recorded from 16 September 2018 to 4 February 2020 utc, we find that all bursts arrive in a five-day phase window, and 50 per cent of the bursts arrive in a 0.6-day phase window. Our results suggest a mechanism for periodic modulation either of the burst emission itself or through external amplification or absorption, and disfavour models invoking purely sporadic processes. A periodicity of roughly 16 days is detected for the fast radio burst 180916.J0158+65, suggesting that the burst arises from a periodically modulated mechanism instead of a cataclysmic or sporadic process.

中文翻译：

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来自快速射电暴源的周期性活动

快速射电暴 (FRB) 是明亮的、持续时间为毫秒的无线电瞬变，起源于河外距离 1，其起源未知。一些 FRB 源发出重复爆发，排除了这些事件 2-4 的灾难性起源。尽管在从毫秒到许多天 2,5-7 的时间尺度上搜索重复爆发到达时间的周期性，但迄今为止观察到这些爆发是零星出现的，并且——尽管是聚集的 8——没有规律的模式。在这里，我们报告了对加拿大氢强度测绘实验快速射电暴项目 4,9 检测到的重复 FRB 180916.J0158+65 的 16.35 ± 0.15 天周期（或可能是该周期的更高频率别名）的观察结果。在 UTC 时间 2018 年 9 月 16 日至 2020 年 2 月 4 日记录的 38 次爆发中，我们发现所有爆发都在五天的阶段窗口内到达，50% 的爆发在 0.6 天的阶段窗口内到达。我们的结果表明了一种周期性调制的机制，无论是突发发射本身还是通过外部放大或吸收，以及不喜欢调用纯粹零星过程的模型。检测到快速射电暴 180916.J0158+65 的周期大约为 16 天，这表明该暴发源于周期性调制机制，而不是灾难性或零星过程。