First fast radio burst to be discovered in the Milky Way is now found to be repeating after being traced back to highly magnetic dead star 32,616 light-years away
- Fast radio bursts are brief but powerful pulses of energy of uncertain origin
- The first one was detected in our galaxy in April and is now repeating
- A team in the Netherlands captured the signal in two short bursts
- Each one was a millisecond long and came in 1.4 seconds apart
- This shows bursts ‘are emitted by magnetars at cosmological distances’
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 have more than one process capable of producing fast radio bursts.
Scroll down for video
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.’
FAST RADIO BURSTS ARE BRIEF 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 hard to find, but also hard to study.
The mystery stems from the fact it is not known what could produce such a short and sharp burst.
This has led some to speculate they could be anything from stars colliding to artificially created messages.
Scientists searching for fast radio bursts (FRBs) that some believe may be signals sent from aliens may be happening every second. The blue points in this artist’s impression of the filamentary structure of galaxies are signals from FRBs
The first FRB was spotted, or rather ‘heard’ by radio telescopes, back in 2001 but wasn’t discovered until 2007 when scientists were analysing archival data.
But it was so temporary and seemingly random that it took years for astronomers to agree it wasn’t a glitch in one of the telescope’s instruments.
Researchers from the Harvard-Smithsonian Center for Astrophysics point out that FRBs can be used to study the structure and evolution of the universe whether or not their origin is fully understood.
A large population of faraway FRBs could act as probes of material across gigantic distances.
This intervening material blurs the signal from the cosmic microwave background (CMB), the left over radiation from the Big Bang.
A careful study of this intervening material should give an improved understanding of basic cosmic constituents, such as the relative amounts of ordinary matter, dark matter and dark energy, which affect how rapidly the universe is expanding.
FRBs can also be used to trace what broke down the ‘fog’ of hydrogen atoms that pervaded the early universe into free electrons and protons, when temperatures cooled down after the Big Bang.
Source: Read Full Article