A sudden change and recovery in the magnetic environment around a repeating fast radio burst
Y. Li, Songbo Zhang, Y. P. Yang, C. W. Tsai, X. Yang, C. J. Law, R. Anna-Thomas, X. L. Chen, K. J. Lee, Z. F. Tang, D. Xiao, H. Xu, Xiaoli Yang, G. Chen, Yibin Feng, Dongzi Li, Ryan Mckinven, Jiarui Niu, Kaitlyn Shin, B. J. Wang, C. F. Zhang, Y. K. Zhang, Dongmeng Zhou, Y. H. Zhu, Zi-Gao Dai, C. M. Chang, Jin-Jun Geng, J. L. Han, L. Hu, D. Li, Rui Luo, C. H. Niu, Dong Shi, T. R. Sun, Xue-Feng Wu, W. W. Zhu, P. Jiang, B. Zhang
Abstract
Fast radio bursts (FRBs) are millisecond-duration radio transients from extragalactic sources. Some repeating FRBs exhibit variations in their Faraday rotation measure (RM) due to changes in their magneto-ionic environment. We report magneto-ionic variations of FRB 20220529, a repeating FRB from a disk galaxy at redshift 0.18. For the first 17 months of observations, the RM had a median of 17 radians per square meter (rad m −2 ) and a scatter of 101 rad m −2 . In December 2023, the RM jumped to 1977 ± 84 rad m −2 , then gradually returned to typical values within 2 weeks. This sudden RM variation indicates that a dense magnetized clump of plasma passed across the line of sight. We discuss potential explanations, including a coronal mass ejection from a companion star, high plasma turbulence, or binary orbital motion.