Fast radio bursts (FRBs) are the brightest millisecond-long cosmic bursts in the radio bands. Its unknown origins pose problems for astronomy and physics. The Commensal Radio Astronomy FAST Survey (CRAFTS), the flagship program of the Global Radio Telescope, has discovered the world’s first continuously active repeating FRB, known as FRB 20190520B. This FRB has now provided clues that can help clarify the origin of the FRB.

From the National Astronomical Observatory of the Chinese Academy of Sciences (NAOC), Dr. An international team led by Li Di conducted a monitoring campaign for FRB 20190520B using the Parkes Telescope in Australia and the Green Bank Telescope (GBT) in the United States. . Combined analysis revealed an extraordinary field reversal around this continuous explosive source.

The study, based on observations made on three continents, Science 11 May

Unlike all other FRBs, FRB 20190520B produces flares that can be detected by at least one and sometimes several telescopes each time it is observed. This robustness makes it an ideal target for multi-band monitoring observational studies.

Dr Dai Shi, PI, from the University of Western Sydney, said: “A total of 113 bursts from FRB 20190520B were detected by the Parkes telescope, exceeding the sum of the fast radio bursts previously detected at Parkes, highlighting the value of FRB 20190520B.” of the FRB 20190520B project in Parks.

Through the combined analysis of GBT and Parkes data, Dr. Feng Yi, NAOC Ph.D. Reshma Anna-Thomas, a graduate of Zhejiang Laboratory and West Virginia University (WVU), measured polarization properties and found that the Faraday rotation measure (RM) changed sign significantly twice, from ~10,000 units to ~-10,000 units and vice versa. Among those found were Caltech’s Dr. Liam Connor and WVU’s Dr. Sarah Burke-Spolaor.

During the propagation of the explosive signal, the polarization properties can be affected by the surrounding plasma. “The RM can be estimated by the integral product of the magnetic field and electron density. The RM variation can be caused by any factor, but the change in sign must be due to the change in magnetic fields, because electron density cannot be negative,” said study co-author Dr. Li Di.

This reversal may be the result of propagation across a turbulent magnetized plasma screen located 10 meters away.^-5 Up to 100 parsecs from the FRB source. “The turbulent components of the magnetic field around the repetitive fast radio emissions can be as diffuse as a ball of wool,” said Professor Yang Yuanpei of Yunnan University, co-author of the study.

One possible scenario for creating such confusion involves the signal passing through an accompanying halo, whether it’s a black hole or a large windy star. Understanding the dramatic changes in the magnetized environment around FRBs is an important step towards understanding the origin of such cosmic explosions.