Fast radio bursts, or FRBs, are incredibly short but powerful blasts from distant sources in space that have so far escaped explanation. Although the bursts only last a fraction of a second, astronomers have said they can be millions of times more powerful than the Sun. And one such blast was recently picked up in our galactic neighbourhood.
A team of scientists in Canada, including some 50 students, postdoctoral researchers and professors, detected earlier this spring an unusually powerful radio burst from a nearby magnetar – a neutron star with an extremely powerful magnetic field.
The burst was detected on April 28 by the Canadian Hydrogen Intensity Mapping Experiment (CHIME) Fast Radio Burst Collaboration and presented to the world today (November 4) in the journal Nature.
Not only is it the closest radio burst to Earth astronomers have ever observed, but it may also have finally solved a 13-year-long mystery of where FRBs originate from.
In their study, the researchers described a radio burst that was 3,000 times stronger than of any magnetar measured so far.
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The data gives credence to the theory some FRBs originate in magnetars.
Pragya Chawla, a PhD student at McGill University and study co-author, said: “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.”
The first FRB was discovered by chance in 2007 when two scientists trawled archival data from a pulsar survey.
The anomaly has since come to be known as the Lorimer Burst after West Virginia University astronomer Duncan Lorimer who discovered it with his student David Narkevic.
However, the origin of the burst has remained a mystery and subsequent FRB detections have not yielded definite answers.
FRBs were originally assumed to be one-off astronomical events caused by some unknown high-energy cosmic process.
Astronomers now know some of these events repeat, such as FRB 180916, which appears to recur about every 16 days.
Many of these FRBs are millions to billions of more times more powerful than our Sun and have been traced to sources outside of our home galaxy.
That was until the CHIME collaboration discovered the FRB linked to magnetar SGR 1935+2154.
Ziggy Pleunis, study co-author and PhD student at McGill, said: “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.
“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.”
Chris Bochenek, a PhD student at the California Institute of Technology who led one study of the radio burst, added: “Before this event, a wide variety of scenarios could explain the origin of FRBs.
“While there may still be exciting twists in the story of FRBs in the future, for me, right now, I think it’s fair to say that most FRBs come from magnetars until proven otherwise.”
And Dr Paul Scholz from the Dunlap Institute of Astronomy and Astrophysics at the University of Toronto said: “The radio burst was far brighter than anything we had seen before, so we immediately knew it was an exciting event.
“We’ve studied magnetars in our galaxy for decades, while FRBs are an extragalactic phenomenon whose origins have been a mystery. This event shows that the two phenomena are likely connected.”
The astronomer added: “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.”