Chinese scientists reveal physical mechanism of fast radio burst generated by magnetar

This aerial panoramic photo taken on July 26, 2023 shows China's Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in southwest China's Guizhou Province. (Xinhua/Ou Dongqu)

BEIJING, Aug. 3 (Xinhua) -- An international research team used China's Five-hundred-meter Aperture Spherical Radio Telescope (FAST) to observe a magnetar, providing clues on how it generates fast radio bursts (FRBs), according to the National Astronomical Observatories of China (NAOC).

FRBs are bright, powerful emissions of radio waves ranging from a fraction of a millisecond to a few milliseconds, each producing energy equivalent to the sun's annual output. Their origin and physical mechanism is one of the hottest research topics in astrophysics.

Researchers from the NAOC, Peking University, University of Nevada, Beijing Normal University, and other institutes from China, the United States and Turkey used FAST to conduct multi-band observations of SGR J1935+2154, a magnetar located in the Milky Way, for a month. They successfully detected the magnetar's single-pulse pulsar radiation.

SGR J1935+2154 experienced an explosion on April 28, 2020, and a very bright radio burst from it was captured by ground-based radio telescopes. The radio burst from the magnetar reached the brightness of certain extragalactic FRBs, making it the first known FRB phenomenon from within the Milky Way.

Since 2020, the magnetar has sporadically experienced several bright radio bursts similar to FRBs. These bright radio bursts provide important information for studying the mechanisms behind FRBs.

By comparing the phases of its pulsar radiation and X-ray radiation profile, the researchers found that the phase distribution of the FRB is different from that of pulsar radiation, with the phase of FRB occurring more randomly.

The results suggest that the generation mechanism of FRBs is likely different from that of pulsar radiation. They may occur during violent processes that can disrupt the stable structure of the magnetic field, thus appearing at random rotational phases.

This conclusion is of great significance for understanding the generation mechanism of FRBs and may explain why repeating FRBs rarely show significant spin periodicity.

The study was recently published in the journal Science Advances.