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The first radio flash discovered in the Milky Way is repeating itself as it travels from a magnetar – a neutron star with a strong magnetic field – 32,616 light-years away.
The initial energy burst was first detected in April, and scientists have identified two more, confirming that the fast radio bursts “are emitted by magnetars at cosmological distances.”
A team working with the Westerbrok telescope in the Netherlands captured the signal, which arrived as two short bursts, each one millisecond long and 1.4 seconds apart.
Furthermore, the bursts were not emitted with the same intensity, which suggests that the magnetars may have more than one process capable of producing fast radio bursts.
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The initial energy burst was first detected in April and scientists have identified two more, confirming that the fast radio bursts “are emitted by magnetars at cosmological distances.”
Fast radio bursts (FRBs) are mysterious, short pulses, and although their origins are unclear, scientists use these bursts of energy to study space along their path to Earth.
The magnetar studied, or “SGR 1935 + 2154”, is the closest source of an explosion detected to date – the next closest being about 490 million light-years away in another galaxy.
The initial outbreak, which is the first to be detected in our galaxy, was observed in April by telescopes located in Canada and the United States.
The two recent ones, identified by Chalmers University of Technology, were captured by four European radio telescopes aimed at SGR 1935 + 2154.
A team working with the Westerbrok telescope in the Netherlands captured the signal, which arrived as two short bursts, each one millisecond long and 1.4 seconds apart.
One dish is found in the Netherlands and another in Poland, along with two at the Onsala Space Observatory in Sweden.
Combine, the telescopes monitored the neutron star every night for more than four weeks after April.
Mark Snelders, team member of 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 entirely new. We were hoping to be surprised! ‘
After recording 522 hours of observations, a small team monitoring the telescope in the Netherlands received “a dramatic and unexpected signal”.
Kenzie Nimmo, astronomer at the 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 one looked just like the fast radio bursts we had seen from the distant universe, only fainter. The two explosions we detected on May 24 were even weaker than that.
Magnetars – the rotating 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 reserves of energy that may be capable of powering fast radio bursts, which could be released directly from the star’s surface – in the form of a so-called “earthquake” – or from the magnetized environment.
After recording 522 hours of observations, a small team monitoring the telescope in the Netherlands (pictured) received “ a dramatic and unexpected signal
Jason Hessels, with the Anton Pannekoek Institute for Astronomy and ASTRON, The Netherlands, said: ‘The brightest flashes of this magnetar are at least ten million times brighter than the faintest ones.
‘We asked ourselves, could this also be true for fast radio burst sources outside our own galaxy?
‘If so, then the universe’s magnetars are creating beams of radio waves that could traverse the cosmos all the time, and many of them 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 reveal more about the parts of the universe they travel through before reaching Earth.
The team plans to keep the group of radio telescopes pointed at SGR 1935 + 2154 and other nearby magnetars, in hopes of finding out how these extreme stars produce their brief bursts of radiation.
Franz Kirsten, astronomer at the Onsala Space Observatory, Chalmers, who led the project, said: “The fireworks from this fantastic nearby magnetar have provided us with exciting clues as to how fast radio bursts could be generated.”
“The explosions we detected on May 24 could indicate a dramatic disturbance in the star’s magnetosphere, near its surface.”
“Other possible explanations, such as shock waves further away from the magnetar, seem less likely, but I’d be glad to be proven wrong.”
“Whatever the answers, we can expect new measurements and new surprises in the months and years to come.”
FAST RADIO BURSTS ARE SHORT RADIO EMISSIONS FROM SPACE WHOSE ORIGIN IS UNKNOWN
Fast radio bursts, or FRBs, are radio emissions that appear temporarily and randomly, making them not only difficult to find, but also difficult to study.
The mystery arises from the fact that it is not known what could produce such a short and sharp burst.
This has led some to speculate that they could be anything from colliding stars to artificially created messages.
Scientists looking for fast radio bursts (FRBs) that some believe may be signals sent by aliens could occur every second. The blue dots in this artist’s impression of the filamentous structure of galaxies are signals of FRB
The first FRB was identified, or rather “listened to” by radio telescopes, in 2001, but was not discovered until 2007, when scientists were analyzing archive data.
But it was so temporary and seemingly random that it took years for astronomers to agree that it wasn’t a glitch in one of the telescope’s instruments.
Researchers at the Harvard-Smithsonian Center for Astrophysics point out that FRBs can be used to study the structure and evolution of the universe regardless of whether their origin is fully understood or not.
A large population of distant FRBs could act as probes of material over gigantic distances.
This intermediate material blurs the signal from the cosmic microwave background (CMB), the residual radiation from the Big Bang.
A careful study of this intermediate material should provide a better understanding of the basic cosmic constituents, such as the relative amounts of ordinary matter, dark matter, and dark energy, which affect how quickly the universe is expanding.
FRBs can also be used to track what broke down the “fog” of hydrogen atoms that pervaded the early universe in free electrons and protons, when temperatures cooled after the Big Bang.
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