Magnetars could be behind some fast radio bursts, shows study

Credit: NASA.

Magnetars—a type of neutron star believed to have an extremely powerful magnetic field—could be the source of some fast radio bursts, new research suggests.

Though a lot of research has aimed to explain the mysterious phenomenon, the source has thus far remained elusive and the subject of some debate.

On April 28, 2020, a team of approximately 50 students, postdocs, and professors from the Canadian Hydrogen Intensity Mapping Experiment (CHIME) Fast Radio Burst Collaboration detected an unusually intense radio burst emanating from a nearby magnetar located in the Milky Way.

In a study in Nature, they show that the intensity of the radio burst (FRB) was three thousand times greater than that of any magnetar measured thus far, lending weight to the theory that magnetars are at the origin of at least some FRBs.

“We calculated that such an intense burst coming from another galaxy would be indistinguishable from some fast radio bursts, so this really gives weight to the theory suggesting that magnetars could be behind at least some FRBs,” says coauthor Pragya Chawla, a senior PhD student in the physics department at McGill University.

FRBs were first discovered over a decade ago.

Originally thought to be singular events, astronomers have since discovered that some of these high-intensity blasts of radio emissions—more intense than the energy generated by the sun over millions to billions of years—in fact repeat.

One theory hypothesized FRBs to be extragalactic magnetars—young extremely magnetic neutron stars that occasionally flare to release enormous amounts of energy.

“So far, all of the FRBs that telescopes like CHIME have picked up were in other galaxies, which makes them quite hard to study in great detail,” says coauthor Ziggy Pleunis, a senior PhD student in the physics department.

“Moreover, the magnetar theory was not supported by observations of magnetars in our own galaxy as they were found to be far less intense than the energy released by extragalactic FRBs until now.”

“However, given the large gaps in energetics and activity between the brightest and most active FRB sources and what is observed for magnetars, perhaps younger, more energetic and active magnetars are needed to explain all FRB observations,” adds Paul Scholz of the Dunlap Institute of Astronomy and Astrophysics at the University of Toronto.

Smoking-gun proof of a magnetar origin for some FRBs would come from the simultaneous detection of an extragalactic radio burst and an X-ray burst.

Original study