In 2007, a team of American astronomers detected among data acquired a few years earlier, strange radio wave surges, whose duration did not exceed a few milliseconds. Then called FRB, for fast radio burst, such pulsations had for the time being never been detected again. Until a beautiful day last summer…
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In August 2018, a Canadian team indeed captured in the space of three weeks not less than thirteen new rapid radio bursts. Of these thirteen very short-lived signals - detected through the Canadian Hydrogen Intensity Mapping Experiment (CHIME) - one of them attracted the attention of scientists. Its name: FRB 180814.J0422 + 73, and its particularity was that it repeated itself no less than six times.
‘Until now, there was only one known repetitive FRB. But know that there is the possibility that there could be even more,’ said astrophysicist Ingrid Stairs in a statement, from the University of British Columbia, Canada, and a member of the team behind the two discoveries.
Born from an unknown source
A vast question remains unanswered, what could be the source of such a rapid radio burst? This is difficult for the moment to answer with certainty. All that the scientists are certain of in any case is that the signal was emitted from a galaxy some 1.5 billion light-years away from us. An inaccessible region, but astronomers can still estimate some of its characteristics.
‘[The burst could come from] a kind of dense cluster like the remains of a supernova, or the edge of the central black hole of a galaxy,’ said astronomer Cherry Ng, from the University of Toronto, in Canada. For its part, the theorist Avi Loeb estimated in 2017 that such waves could potentially come from ‘an artificial origin,’ in other words, from aliens... A scenario closer to a science fiction story than reality but which, according to the expert, ‘is worth considering and verifying.’
A wide range of frequencies
Arun Naidu from McGill University in Canada points out that ‘regardless of the source of these radio waves, it is interesting to see the wide range of frequencies it can produce.’ The thirteen new fast radio bursts detected have the peculiarity of having been emitted at a much lower frequency than their predecessors in 2007: 400 megahertz instead of 700. The lowest frequency ever recorded for such a phenomenon.
‘We now know that [sources] can produce low-frequency radio waves and that these low-frequency waves can escape from their [original] environment, giving us insights into both the environment and the sources. We have not solved the problem, but it brings many more pieces to the puzzle,’ says physicist Tom Landecker from the National Research Council of Canada (NRC). Bursts of a few milliseconds that definitely promise years of work for the astronomers.
Check out the video above for more on the mysterious signals!
