Fast radio bursts just keep getting weirder
Discovery of rare pulsing high-energy radio burst may help cosmologists to learn more about these mysterious cosmic phenomena.
Astronomers from The National Radio Astronomy Observatory in the US have found that a fast radio burst (FRB), FRB190520, that was first discovered in 2019 shares an odd characteristic with just one other FRB of the 500-plus that have so far been discovered. It’s hoped their findings may help shed new light on the origins of these mysterious cosmic phenomena.
Fast radio bursts are exactly what the name implies – an intense but short-lived burst of energy in the radio spectrum. Exactly how intense and short-lived are we talking here? Try emitting as much energy in a couple of milliseconds as the Sun does in three days on for size!
FRBs are a relatively new area of study – the first was only discovered in 2007, lurking in radio telescope data that had been gathered in 2001, and scientists had never actually observed one taking place 'live' (or rather, seen the resulting afterglow) until a team at Australia’s Parkes Observatory did just that in 2015. As such, there is still much about them that is unknown – not least what actually causes them.
Various points of origin have been mooted for FRBs, including neutron stars, gamma ray bursts, black holes, star collisions and magnetars, a subset of neutron stars that are magnetically ultra-charged, but scientists have yet to pin down a precise cause.
It may even be that more than one type of cosmological object or event can cause the phenomenon – not least because while most FRBs appear to be one-off events, some repeat in a regular, predictable cycle. Which is where FRB190520 comes in.
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Like most bursts, FRB190520 was discovered by trawling through archived telescope data – the burst occurred on 19 May 2019, but wasn’t ‘seen’ until November that year. But astronomers soon realised that this was one of the rarer ‘repeater’ class; what has only more recently been discovered is that, in-between those regular high-energy bursts, whatever is causing FRB190520 is also the source of constant, much lower-energy radio emissions, a characteristic it shares only with FRB121102.
The scientists now hope that by studying the differences between these two FRBs and all the others, they may be able learn more about the phenomenon’s origins.
"The FRB field is moving very fast right now and new discoveries are coming out monthly. However, big questions still remain, and this object is giving us challenging clues about those questions," said Sarah Burke-Spolaor, of WVU.
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Russell Deeks is a freelance writer with nearly 30 years’ journalism experience, working across the fields of music, technology and science – which, he says, cross over more often than you might think. Despite the drawback of holding a degree in English & American Literature, he has been a regular contributor to BBC Science Focus since 2006.