An article published in the journal “Nature” reports the identification of a new fast radio burst which was cataloged as FRB 190520B. A team of researchers made this discovery thanks to the FAST radio telescope in China. Recently, the number of known fast radio bursts has increased significantly but in this case, it’s a repeating phenomenon that makes it rare and particularly interesting. FRB 190520B has characteristics that are different from other fast radio bursts because it repeats, just like the one cataloged as FRB 121102. Magnetar-type neutron stars are the most likely candidates as sources of these emissions and the magnetar that generates FRB 190520B may have just formed after a supernova.
Fast radio bursts were detected for the first time in 2007 by analyzing archive data collected in 2001 and are still a mystery because such powerful radio emissions require an estimated energy that’s about what the Sun emitted in 80 years despite their duration of a few milliseconds.
Of the hundreds of known fast radio bursts, nearly all are single events, so finding a repeating one is important for astronomical research. FRB 190520B was discovered during the Commensal Radio Astronomy FAST Survey (CRAFTS) conducted using the Five-hundred-meter Aperture Spherical radio Telescope (FAST) on May 20, 2019. Initial observations recorded 4 bursts.
Follow-up observations conducted with the Very Large Array (VLA) radio telescope made it possible to locate the origin of FRB 190520B in a dwarf galaxy nearly three billion light-years from Earth. New follow-up observations conducted with FAST between April and September 2020 recorded 75 more bursts.
The fast radio burst FRB 121102 was studied in-depth and various clues led teams of astronomers to conclude that the source is a magnetar, a neutron star with an extremely powerful magnetic field. The differences between the emissions of the known fast radio bursts leave various possibilities open: there could be different mechanisms that generate them or magnetars generate emissions with different characteristics depending on their phase of evolution.
According to the researchers, the FRB 190520B fast radio burst could be generated by a newly formed magnetar. Neutron stars are one of the possible remnants of a star after a supernova and for a long time, it’s surrounded by materials ejected from its progenitor. It’s possible that young magnetars generate regular radio emissions from interactions with those materials and consequently, they weaken over time as they disperse into interstellar space. The discovery of more repeating fast radio bursts is needed in order to test this hypothesis.
Part of the research connected to the fast radio flash FRB 190520B concerns the effects of materials, particularly electrons, between it and the Earth on the radio waves emitted. Those effects help estimate the distance to the object with a technique that’s already used with pulsars, another type of neutron star. Basically, while waiting to discover more phenomena of this type, there are astronomers who are already studying how to use them for other astronomical research.
