A flare from a magnetar. (Image Credit: NASA/GSFC).
The object is a reliable repeater, with fast radio bursts observed every time a telescope turned towards it
Chinese astronomers have carried out a monitoring campaign on a repeating fast radio burst (FRB) designated as FRB 20190520B, which produce among the brightest cosmic explosions in radio bands that last for a few milliseconds. Scientists do not know what process causes FRBs, with repeating sources being even more mysterious. FRB 20190520B has proven to be a reliable repeater, with FRBs being detected every time the source has been observed by astronomical instruments.
The researchers monitored FRB 20190520B Parkes telescope in Australia Green Bank Telescope in the United States. The observations have revealed twisted magnetic fields around the constantly bursting source, with extreme reversals. As the burst signal propogates, the heated gas surrounding the source can affect the polarisation characteristics.
The twisted fields around the repeating FRB. (Image Credit: LI Di/ScienceApe/CAS).
The twisted magnetic fields surrounding the repeating FRB is comparable to a messed up ball of wool, that has repeatedly been pulled or pushed in different directions. Astronomer Dai Shi from Western Sydney University says, “A total of 113 bursts from FRB 20190520B were detected by the Parkes telescope, exceeding the sum of the number of fast radio bursts previously discovered at Parkes, accentuating the value of FRB 20190520B.”
Researchers suspect that the signal from the FRB, which is likely to be an exotic stellar remnant such as a magnetar, passed through the outer atmosphere or corona of a companion, which could be a black hole with massive winds, or the stellar winds from an energetic, massive star. The researchers believe that the FRB passed through a magnetic screen of plasma located for a distance of up to 325 lightyears from the source. Scientists can gain more insights on the nature and processes within the objects that produce repeating FRBs by studying the environment surrounding them.