Nimmo Kenzie, Pleunis Ziggy, Beniamini Paz, Kumar Pawan, Lanman Adam E, Li D Z, Main Robert, Sammons Mawson W, Andrew Shion, Bhardwaj Mohit, Chatterjee Shami, Curtin Alice P, Fonseca Emmanuel, Gaensler B M, Joseph Ronniy C, Kader Zarif, Kaspi Victoria M, Lazda Mattias, Leung Calvin, Masui Kiyoshi W, Mckinven Ryan, Michilli Daniele, Pandhi Ayush, Pearlman Aaron B, Rafiei-Ravandi Masoud, Sand Ketan R, Shin Kaitlyn, Smith Kendrick, Stairs Ingrid H
MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA, USA.
Dunlap Institute for Astronomy and Astrophysics, University of Toronto, Toronto, Ontario, Canada.
Nature. 2025 Jan;637(8044):48-51. doi: 10.1038/s41586-024-08297-w. Epub 2025 Jan 1.
Fast radio bursts (FRBs) are microsecond-to-millisecond-duration radio transients that originate mostly from extragalactic distances. The FRB emission mechanism remains debated, with two main competing classes of models: physical processes that occur within close proximity to a central engine; and relativistic shocks that propagate out to large radial distances. The expected emission-region sizes are notably different between these two types of models. Here we present the measurement of two mutually coherent scintillation scales in the frequency spectrum of FRB 20221022A: one originating from a scattering screen located within the Milky Way, and the second originating from its host galaxy or local environment. We use the scattering media as an astrophysical lens to constrain the size of the observed FRB lateral emission region to ≲3 × 10 kilometres. This emission size is inconsistent with the expectation for the large-radial-distance models, and is more naturally explained by an emission process that operates within or just beyond the magnetosphere of a central compact object. Recently, FRB 20221022A was found to exhibit an S-shaped polarization angle swing, most likely originating from a magnetospheric emission process. The scintillation results presented in this work independently support this conclusion, while highlighting scintillation as a useful tool in our understanding of FRB emission physics and progenitors.
快速射电暴（FRBs）是持续时间从微秒到毫秒的射电瞬变现象，大多起源于河外距离。快速射电暴的发射机制仍存在争议，主要有两类相互竞争的模型：在靠近中央引擎的区域内发生的物理过程；以及传播到较大径向距离的相对论性激波。这两类模型中预期的发射区域大小明显不同。在此，我们展示了对快速射电暴20221022A频谱中两个相互相干的闪烁尺度的测量：一个源于位于银河系内的散射屏，另一个源于其宿主星系或局部环境。我们将散射介质用作天体物理透镜，将观测到的快速射电暴横向发射区域的大小限制在≲3×10公里。这个发射大小与大径向距离模型的预期不一致，更自然的解释是由在中央致密天体的磁层内或刚超出磁层的发射过程造成的。最近，发现快速射电暴20221022A表现出S形偏振角摆动，很可能源于磁层发射过程。这项工作中呈现的闪烁结果独立地支持了这一结论，同时突出了闪烁作为我们理解快速射电暴发射物理和前身星的有用工具。
