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arXiv · 2512.05448

A Persistently Active Fast Radio Burst source Embedded in an Expanding Supernova Remnant

Chen-Hui Niu·Di Li·Yuan-Pei Yang·Yuhao Zhu·Yongkun Zhang·Jia-heng Zhang·Zexin Du·Jumei Yao·Xiaoping Zheng·Pei Wang·Yi Feng·Bing Zhang·Weiwei Zhu·Wenfei Yu·Ji-an Jiang·Shi Dai·Chao-Wei Tsai·A. M. Chen·Yijun Hou·Jiarui Niu·Weiyang Wang·Chenchen Miao·Xinming Li·Junshuo Zhang
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Abstract

Fast radio bursts (FRBs) remain one of the most puzzling astrophysical phenomena. While most FRBs are detected only once or sporadically, we present the identification of FRB 20190520B as the first persistently active source over a continuous span of ~ four years. This rare long-term activity enabled a detailed investigation of its dispersion measure (DM) evolution. We also report that FRB 20190520B exhibits a substantial decrease in DM at a global rate of minus 12.4 plus or minus 0.3 pc cm^-3 yr^-1, exceeding previous FRB DM variation measurements by a factor of three and surpassing those observed in pulsars by orders of magnitude. The magnitude and consistency of the DM evolution, along with a high host DM contribution, strongly indicate that the source resides in a dense, expanding ionized medium, likely a young supernova remnant (SNR).

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Chen-Hui Niu, Di Li, Yuan-Pei Yang, Yuhao Zhu, Yongkun Zhang, Jia-heng Zhang, Zexin Du, Jumei Yao, Xiaoping Zheng, Pei Wang, Yi Feng, Bing Zhang, Weiwei Zhu, Wenfei Yu, Ji-an Jiang, Shi Dai, Chao-Wei Tsai, A. M. Chen, Yijun Hou, Jiarui Niu, Weiyang Wang, Chenchen Miao, Xinming Li, Junshuo Zhang. 2025-12-05. A Persistently Active Fast Radio Burst source Embedded in an Expanding Supernova Remnant. https://doi.org/10.1016/j.scib.2025.11.023

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