Fast radio bursts (FRBs), typically highly polarized, usually have a nearly constant polarization position angle (PA) during each burst. Some bursts show significant PA variations, and one of them was claimed to have a PA variation pattern consistent with the prediction of the rotating vector model (RVM) commonly adopted to fit the PA variations in radio pulsars. We systematically study the PA evolution pattern of 1727 bursts from three active repeating FRB sources monitored by the Five-hundred-meter Aperture Spherical Telescope (FAST). We identify 46 bursts whose PA variations are fully consistent with the RVM. However, the inferred geometrical parameters and rotation periods derived from these RVM fitting are inconsistent from each other. This suggests that the magnetosphere of the FRB central engine is constantly distorted by the FRB emitter, and the magnetic configuration is dynamically evolving.
@article{arxiv.2504.00391,
title = {Polarization Position Angle Swing and the Rotating Vector Model of Repeating Fast Radio Bursts},
author = {Xiaohui Liu and Heng Xu and Jiarui Niu and Yongkun Zhang and Jinchen Jiang and Dejiang Zhou and Jinlin Han and Weiwei Zhu and Kejia Lee and Di Li and Wei-Yang Wang and Bing Zhang and Xuelei Chen and Jia-Wei Luo and Rui Luo and Chenhui Niu and Yuanhong Qu and Bojun Wang and Fayin Wang and Pei Wang and Tiancong Wang and Qin Wu and Ziwei Wu and Jiangwei Xu and Yuan-Pei Yang and Jun-Shuo Zhang},
journal= {arXiv preprint arXiv:2504.00391},
year = {2025}
}