Regular Fast Radio Burst detected outside our galaxy
Probably not ET, but possibly a new way to weigh the universe
Fast Radio Bursts (FRBs) have gone from mysterious to intriguing, intriguing to exciting, exciting to maybe-explained, and just took a jump back to mysterious.
That's because the latest observations of the Fast Radio Burst (FRB) phenomenon, published in Nature, has turned up an FRB that repeats.
That suggests either that the theories put forward to explain FRBs – that they arise out of cataclysmic events like neutron star collisions – were wrong, or even better, that there's more than one mechanism that can produce FRBs.
From archives to real-time
FRBs were first identified by University of Manchester student Dan Thornton in archival data collected by the Parkes Radio Telescope in Australia. In 2015, Emily Petroff at Swinburne University made the first real-time observation of an FRB.
Although their origins were mysterious, FRBs excited astro-boffins, who reckoned the behaviour of the beacons would help them search for the universe's missing baryonic matter.
In February, The Commonwealth Scientific and Industrial Research Organisation (CSIRO) and Japan's National Astronomical Observatory of Japan’s (NAOJ) Subaru telescope in Hawaii announced they'd identified the location of one of the elusive bursts – a galaxy six billion light-years away.
At the time, CSIRO astrophysics boss Dr Simon Johnson raised the possibility that FRBs could be the signature of a collision between neutron stars, because the host galaxy is too old for the bursts to come from star formation.
Wisely, it turns out, he also said “there could be more than one road to an FRB” – and that's where the new observation comes in.
Burst and repeat
As Scientific American explains, the repeating FRB is in a patch of sky one-tenth the size of the moon, in the direction of the constellation Auriga.
Co-author of the Nature paper, Cornell University astronomer James Cordes, points out that for this object, the millisecond chirps of radio waves can't come from a one-off event. Instead, it looks like it could come from a rotating neutron star.
That's going to be hard to model: instead of regular pulses that you might expect, the Auriga FRB showed up in eight bursts on one day, two bursts on another, and a lot of time passing where nothing happened.
The group doesn't have a fix on the distance to their object, yet, so the error bars in their estimates are huge: it could be in a galaxy a few hundred million light years distant, or in a “plasma-rich galaxy much closer”.
However, if the new FRB can be pinpointed – and if the CSIRO result is borne out, although a Harvard-Smithsonian Center for Astrophysics team has cast doubt on that result – then astrophysics' greatest hope, that FRBs can help us weigh the cosmos, will be more likely to bear fruit. ®
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