A fast radio burst source at a complex magnetised site in a barred galaxy
Abstract
Fast radio bursts (FRBs) are highly dispersed millisecond-duration radio bursts. Recent observations of a Galactic FRB suggest that at least some FRBs originate from magnetars, but the origin of cosmological FRBs is still not settled. Here we report the detection of 1863 bursts in 82 hr over 54 days from the repeating source FRB~20201124A. These observations show irregular short-time variation of the Faraday rotation measure (RM), which probes the density-weighted line-of-sight magnetic field strength, of individual bursts during the first 36 days, followed by a constant RM. We detected circular polarisation in more than half of the burst sample, including one burst reaching a high fractional circular polarisation of 75%. Oscillations in fractional linear and circular polarisations as well as polarisation angle as a function of wavelength were detected. All of these features provide evidence for a complicated, dynamically evolving, magnetised immediate environment within about an astronomical unit (au; Earth-Sun distance) of the source. Our optical observations of its Milky-Way-sized, metal-rich host galaxy reveal a barred spiral, with the FRB source residing in a low stellar density, interarm region at an intermediate galactocentric distance. This environment is inconsistent with a young magnetar engine formed during an extreme explosion of a massive star that resulted in a long gamma-ray burst or superluminous supernova.
Keywords
Cite
@article{arxiv.2111.11764,
title = {A fast radio burst source at a complex magnetised site in a barred galaxy},
author = {H. Xu and J. R. Niu and P. Chen and K. J. Lee and W. W. Zhu and S. Dong and B. Zhang and J. C. Jiang and B. J. Wang and J. W. Xu and C. F. Zhang and H. Fu and A. V. Filippenko and E. W. Peng and D. J. Zhou and Y. K. Zhang and P. Wang and Y. Feng and Y. Li and T. G. Brink and D. Z. Li and W. Lu and Y. P. Yang and R. N. Caballero and C. Cai and M. Z. Chen and Z. G. Dai and S. G. Djorgovski and A. Esamdin and H. Q. Gan and P. Guhathakurta and J. L. Han and L. F. Hao and Y. X. Huang and P. Jiang and C. K. Li and D. Li and H. Li and X. Q. Li and Z. X. Li and Z. Y. Liu and R. Luo and Y. P. Men and C. H. Niu and W. X. Peng and L. Qian and L. M. Song and D. Stern and A. Stockton and J. H. Sun and F. Y. Wang and M. Wang and N. Wang and W. Y. Wang and X. F. Wu and S. Xiao and S. L. Xiong and Y. H. Xu and R. X. Xu and J. Yang and X. Yang and R. Yao and Q. B. Yi and Y. L. Yue and D. J. Yu and W. F. Yu and J. P. Yuan and B. B. Zhang and S. B. Zhang and S. N. Zhang and Y. Zhao and W. K. Zheng and Y. Zhu and J. H. Zou},
journal= {arXiv preprint arXiv:2111.11764},
year = {2022}
}
Comments
28 pages, 10 figures, updated to match the published version