A fast radio burst source at a complex magnetized site in a barred galaxy

• Published in: Nature (London) Vol. 609; no. 7928; pp. 685 - 688
• Main Authors: Xu, H., Niu, J. R., Chen, P., Lee, K. J., Zhu, W. W., Dong, S., Zhang, B., Jiang, J. C., Wang, B. J., Xu, J. W., Zhang, C. F., Fu, H., Filippenko, A. V., Peng, E. W., Zhou, D. J., Zhang, Y. K., Wang, P., Feng, Y., Li, Y., Brink, T. G., Li, D. Z., Lu, W., Yang, Y. P., Caballero, R. N., Cai, C., Chen, M. Z., Dai, Z. G., Djorgovski, S. G., Esamdin, A., Gan, H. Q., Guhathakurta, P., Han, J. L., Hao, L. F., Huang, Y. X., Jiang, P., Li, C. K., Li, D., Li, H., Li, X. Q., Li, Z. X., Liu, Z. Y., Luo, R., Men, Y. P., Niu, C. H., Peng, W. X., Qian, L., Song, L. M., Stern, D., Stockton, A., Sun, J. H., Wang, F. Y., Wang, M., Wang, N., Wang, W. Y., Wu, X. F., Xiao, S., Xiong, S. L., Xu, Y. H., Xu, R. X., Yang, J., Yang, X., Yao, R., Yi, Q. B., Yue, Y. L., Yu, D. J., Yu, W. F., Yuan, J. P., Zhang, B. B., Zhang, S. B., Zhang, S. N., Zhao, Y., Zheng, W. K., Zhu, Y., Zou, J. H.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 22.09.2022; Nature Publishing Group
• Subjects: 639/33/34/4118; 639/33/34/4121; 639/33/34/4127; Barred galaxies; Bursting strength; Celestial bodies; Circular polarization; Density; Faraday effect; Field strength; Galaxies; Gamma ray bursts; Gamma rays; Humanities and Social Sciences; Magnetars; Magnetic fields; Massive stars; multidisciplinary; Optical observations; Oscillations; Polarization; Radio bursts; Science; Science (multidisciplinary); Supernova
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/s41586-022-05071-8

Fast radio bursts (FRBs) are highly dispersed, millisecond-duration radio bursts 1 – 3 . Recent observations of a Galactic FRB 4 – 8 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 1,863 bursts in 82 h over 54 days from the repeating source FRB 20201124A (ref.  9 ). These observations show irregular short-time variation of the Faraday rotation measure (RM), which scrutinizes 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 polarization in more than half of the burst sample, including one burst reaching a high fractional circular polarization of 75%. Oscillations in fractional linear and circular polarizations, as well as polarization angle as a function of wavelength, were detected. All of these features provide evidence for a complicated, dynamically evolving, magnetized 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 10 – 12 show 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. Analysis of a set of 1,863 bursts from the repeating source FRB 20201124A provides evidence of a complicated magnetized site within about an astronomical unit from the source in a barred galaxy.