ASTRON, Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA Dwingeloo, The Netherlands.
Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
Nature. 2018 Jan 10;553(7687):182-185. doi: 10.1038/nature25149.
Fast radio bursts are millisecond-duration, extragalactic radio flashes of unknown physical origin. The only known repeating fast radio burst source-FRB 121102-has been localized to a star-forming region in a dwarf galaxy at redshift 0.193 and is spatially coincident with a compact, persistent radio source. The origin of the bursts, the nature of the persistent source and the properties of the local environment are still unclear. Here we report observations of FRB 121102 that show almost 100 per cent linearly polarized emission at a very high and variable Faraday rotation measure in the source frame (varying from +1.46 × 10 radians per square metre to +1.33 × 10 radians per square metre at epochs separated by seven months) and narrow (below 30 microseconds) temporal structure. The large and variable rotation measure demonstrates that FRB 121102 is in an extreme and dynamic magneto-ionic environment, and the short durations of the bursts suggest a neutron star origin. Such large rotation measures have hitherto been observed only in the vicinities of massive black holes (larger than about 10,000 solar masses). Indeed, the properties of the persistent radio source are compatible with those of a low-luminosity, accreting massive black hole. The bursts may therefore come from a neutron star in such an environment or could be explained by other models, such as a highly magnetized wind nebula or supernova remnant surrounding a young neutron star.
快速射电暴是持续时间为毫秒级的、未知物理起源的星系际无线电闪光。唯一已知的重复快速射电暴源——FRB121102——已被定位到一个红移为 0.193 的矮星系的恒星形成区，并且与一个紧凑的、持久的射电源空间重合。暴源的起源、持久源的性质和局部环境的性质仍不清楚。在这里，我们报告了对 FRB121102 的观测结果，这些观测结果显示，在源(frame)中存在非常高且可变的 Faraday 旋转量测量值，其几乎 100%为线偏振发射（在相隔七个月的两个观测时期，从+1.46×10 弧度/平方米变化到+1.33×10 弧度/平方米），且具有狭窄的（低于 30 微秒）时间结构。大而可变的旋转量测量值表明 FRB121102 处于极端且动态的磁离子环境中，而暴的持续时间很短表明其起源于一颗中子星。到目前为止，这种大的旋转量测量值仅在大质量黑洞（大于约 10000 个太阳质量）的附近观察到。事实上，持久射电源的性质与低光度、吸积大质量黑洞的性质相兼容。因此，这些暴可能来自于这种环境中的一颗中子星，或者可以用其他模型来解释，例如围绕年轻中子星的高度磁化的风星云或超新星遗迹。
