A sudden change and recovery in the magnetic environment around a repeating fast radio burst
- Y. Li
- S. B. 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
- X. L. Yang
- G. Chen
- Y. Feng
- D. Z. Li
- R. Mckinven
- J. R. Niu
- K. Shin
- B. J. Wang
- C. F. Zhang
- Y. K. Zhang
- D. J. Zhou
- Y. H. Zhu
- Z. G. Dai
- C. M. Chang
- J. J. Geng
- J. L. Han
- L. Hu
- D. Li
- R. Luo
- C. H. Niu
- D. D. Shi
- T. R. Sun
- X. F. Wu
- W. W. Zhu
- P. Jiang
- B. Zhang
2026-01-15
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.