What they spotted was astounding. It was described as “the most luminous radio burst ever detected in our galaxy” by Dr Daniele Michilli, an astrophysicist at McGill University. They are brief but incredibly powerful – emitting much more energy in a single millisecond than the sun does all day. Three research papers published in the journal Nature, based on observations made across the world – in Canada, the US, China, and even from space – have potentially uncovered the source. Astronomers do not know what causes FRBs, but the new signal detected from within our galaxy offers some vital information which could help solve the mystery.

Scientists have had trouble tracking down the origin of such blasts because they are so short, unpredictable and originate far away. They must have been formed in some of the most extreme conditions possible in the universe, with suggested explanations including everything from dying stars to alien technology. Because this FRB came from within our own Milky Way, astronomers were able to trace it to its probable source – a type of neutron star which has a strong magnetic field called a magnetar. This cosmic body is the remnant of a star which long ago collapsed in a supernova explosion, about 30,000 light-years away from Earth. Magnetars, like other neutron stars, are incredibly dense. Despite their diameter of potentially just 12 miles (20km) across, they have a mass of about 140% that of the sun – which has a diameter of 800,000 miles (1.4 million km).

 “There’s this great mystery as to what would produce these great outbursts of energy, which until now we’ve seen coming from halfway across the universe,” said Professor Kiyoshi Masui, assistant professor of physics at MIT. Professor Masui, who leads one of the research projects into the FRB, added: “This is the first time we’ve been able to tie one of these exotic fast radio bursts to a single astrophysical object.” However, even if the astronomers’ theory is right at the FRB originated from a magnetar, it still isn’t clear how the highly magnetized neutron stars could produce the bursts of energy and range of electromagnetic emissions at the same time.

The data can also help refine theories for how magnetars could produce fast radio bursts. In an accompanying review also published in Nature, astrophysicist Bing Zhang of the University of Nevada, Las Vegas, outlined the two most compelling scenarios. In one, flares of particles ejected from the magnetar’s surface collide at extreme speeds with surrounding debris, creating a hot, highly magnetized maelstrom that could give off both x-rays and radio waves. In the other, fast radio bursts form as the magnetar’s super-intense magnetic field lines get tangled and disconnected, releasing vast amounts of energy in the process.

However, Zhang and his colleagues also found that the conditions behind a fast radio burst are somewhat rare. Hours before the April 28 burst, the team was monitoring the magnetar with China’s FAST radio telescope, the largest single dish in the world. But FAST didn’t see any fast radio bursts come from the magnetar despite the object giving off 29 x-ray flashes as they were watching. In the press briefing, Zhang pointed out that it’d make sense for magnetars to release fast radio bursts only infrequently. If every magnetar flare that gave off x-rays also spawned radio blasts, astronomers would expect to see a hundred to a thousand times more of them than they have spotted so far.

By Jumana Jabeer