Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA, USA.
Owens Valley Radio Observatory, California Institute of Technology, Pasadena, CA, USA.
Nature. 2020 Nov;587(7832):59-62. doi: 10.1038/s41586-020-2872-x. Epub 2020 Nov 4.
Since their discovery in 2007, much effort has been devoted to uncovering the sources of the extragalactic, millisecond-duration fast radio bursts (FRBs). A class of neutron stars known as magnetars is a leading candidate source of FRBs. Magnetars have surface magnetic fields in excess of 10 gauss, the decay of which powers a range of high-energy phenomena. Here we report observations of a millisecond-duration radio burst from the Galactic magnetar SGR 1935+2154, with a fluence of 1.5 ± 0.3 megajansky milliseconds. This event, FRB 200428 (ST 200428A), was detected on 28 April 2020 by the STARE2 radio array in the 1,281-1,468 megahertz band. The isotropic-equivalent energy released in FRB 200428 is 4 × 10 times greater than that of any radio pulse from the Crab pulsar-previously the source of the brightest Galactic radio bursts observed on similar timescales. FRB 200428 is just 30 times less energetic than the weakest extragalactic FRB observed so far, and is drawn from the same population as the observed FRB sample. The coincidence of FRB 200428 with an X-ray burst favours emission models that describe synchrotron masers or electromagnetic pulses powered by magnetar bursts and giant flares. The discovery of FRB 200428 implies that active magnetars such as SGR 1935+2154 can produce FRBs at extragalactic distances.
自 2007 年发现以来，人们一直致力于揭示银河系外、毫秒级持续的快速射电暴（FRB）的来源。一类被称为磁星的中子星是 FRB 的主要候选源。磁星的表面磁场超过 10 高斯，其衰减为一系列高能现象提供动力。在这里，我们报告了银河系磁星 SGR 1935+2154 产生的毫秒级无线电爆发的观测结果，其辐射通量为 1.5±0.3 毫焦耳毫秒。该事件，FRB 200428（ST 200428A），于 2020 年 4 月 28 日被 STARE2 射电阵在 1281-1468 兆赫波段探测到。在 FRB 200428 中释放的各向同性等效能量比以前在类似时间尺度上观测到的来自蟹状星云脉冲星的任何无线电脉冲的能量高 4×10 倍。FRB 200428 的能量仅比迄今为止观测到的最弱的河外 FRB 低 30 倍，并且与观测到的 FRB 样本来自同一群体。FRB 200428 与 X 射线爆发的同时发生，有利于描述由磁星爆发和巨型耀斑驱动的同步加速器脉泽或电磁脉冲的发射模型。FRB 200428 的发现意味着像 SGR 1935+2154 这样的活动磁星可以在河外星系距离产生 FRB。
