The first radio burst discovered in the Milky Way is now repeating as it travels from a magnetar – a neutron star with a strong magnetic field – 32,616 light-years away.
The initial flash of energy was first detected in April and scientist have identified two more, confirming fast radio bursts ‘are emitted by magnetars at cosmological distances.’
A team working with the Westerbrok Telescope in the Netherlands captured the signal, which came as two short bursts, each one millisecond long and 1.4 seconds apart.
The bursts were also not emitted with the same strength, which suggest magnetars may be a more than one process capable of producing fast radio bursts.
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The initial flash of energy was first detected in April and scientist have identified two more, confirming fast radio bursts ‘are emitted by magnetars at cosmological distances’
Fast radio bursts (FRB) are mysterious, brief pulses and although their origins are unclear, scientists use these flashes of energy to study space along their path to Earth.
The magnetar being studied, or ‘SGR 1935+2154’, is the closest source of a burst detected to date – the next nearest being some 490 million light-years away in another galaxy.
The initial burst, which is the first to be detected in our galaxy, was observed in April by telescopes located in Canada and the US.
The recent two, spotted by Chalmers University of Technology, was captured by four European radio telescopes that were pointed towards SGR 1935+2154.
A team working with the Westerbrok Telescope in the Netherlands captured the signal, which came as two short bursts, each one millisecond long and 1.4 seconds apart
One dish is located in the Netherlands and another in Poland, along with two at Onsala Space Observatory in Sweden.
Combine the telescopes have been monitoring the neutron star every night for more than four weeks after April.
Mark Snelders, team member from the Anton Pannekoek Institute for Astronomy, University of Amsterdam, said: ‘We didn’t know what to expect. Our radio telescopes had only rarely been able to see fast radio bursts, and this source seemed to be doing something completely new. We were hoping to be surprised!’
After logging 522 hours of observations, a small team monitoring the telescope in the Netherlands received ‘a dramatic and unexpected signal.’
Kenzie Nimmo, astronomer at Anton Pannekoek Institute for Astronomy and ASTRON, said: ‘We clearly saw two bursts, extremely close in time.’
‘Like the flash seen from the same source on April 28, this looked just like the fast radio bursts we’d been seeing from the distant universe, only dimmer. The two bursts we detected on May 24 were even fainter than that.’
Magnetars — spinning remnants of some supernova explosions — are extremely dense and are surrounded by extremely powerful magnetic fields that occasionally release radiation, typically in the form of gamma and X-rays, as they decay.
Experts have speculated that magnetars have vast energy reserves that might be able to power fast radio bursts, which could be released from the star’s surface directly — in the form of a so-called ‘starquake’ — or the magnetized surroundings.
After logging 522 hours of observations, a small team monitoring the telescope in the Netherlands (pictured) received ‘a dramatic and unexpected signal
Jason Hessels, with Anton Pannekoek Institute for Astronomy and ASTRON, Netherlands, said: ‘The brightest flashes from this magnetar are at least ten million times as bright as the faintest ones.
‘We asked ourselves, could that also be true for fast radio burst sources outside our galaxy?
‘If so, then the universe’s magnetars are creating beams of radio waves that could be criss-crossing the cosmos all the time — and many of these could be within the reach of modest-sized telescopes like ours.’
Researchers are interested in fast radio bursts not only in their origins, but also because they may reveals more about the parts of the universe they travel through before reaching Earth.
The team plans to keep the group of radio telescopes pointed towards SGR 1935+2154 and other nearby magnetars, in the hope of uncovering how these extreme stars make their brief blasts of radiation.
Franz Kirsten, astronomer at Onsala Space Observatory, Chalmers, who led the project, said: ‘The fireworks from this amazing, nearby magnetar have given us exciting clues about how fast radio bursts might be generated.’
‘The bursts we detected on May 24 could indicate a dramatic disturbance in the star’s magnetosphere, close to its surface.’
‘Other possible explanations, like shock waves further out from the magnetar, seem less likely, but I’d be delighted to be proved wrong.’
‘Whatever the answers, we can expect new measurements and new surprises in the months and years to come.’