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They are called fast radio bursts, or FRBs, and these strange, fleeting, space-coming signals are shrouded in mystery. But thanks to Canada's largest radio telescope, astrophysicists are discovering more and more in their search for what makes these objects vibrate.
The first FRB was discovered in 2007 by an astrophysicist and his student while he was analyzing 2001 data collected by the Parkes Observatory of New South Wales, Australia. Since then, dozens of others have been detected. As far as these signals are concerned, scientists have yet to learn.
But these brief signals that cross the universe – and last only about a millisecond – had another surprise: some of them repeated themselves.
The first of these repeaters was discovered by Paul Scholz, a PhD student at McGill in 2015. A second one was discovered last January. And the list goes on.
In a new study, Submitted to the Astrophysical Journal Letters and pre-prints on arXiv.org, a group of Canadian scientists reveal that the Canadian Hydrogen Intensity Mapping Experience (CHIME) telescope has detected eight other repetitive FRBs.
The results are an important step to better understand what creates these powerful signals and where they come from exactly.
"The first biggest conclusion [from the paper] is not an abnormal phenomenon. That's right, said Victoria Kaspi, an astrophysicist at McGill University and at the Canadian Institute for Advanced Research (CIFAR). It just takes time and patience to find them. And second, it offers the opportunity to locate them, which is huge in the FRB domain. "
The CHIME instrument can not be both sensitive and accurate in its detections, which means that it can not locate the signal. Instead, his job is to find as many as possible. Determine their exact location is at the height of other telescopes.
WATCH: Commissioning of the CHIME telescope
"Discovering eight sources like this is very important because it indicates that we have many more repetitive FRBs and that we can understand the environments and galaxies in which these FRBs are located if we follow them with other telescopes" said Pragya Chawla, co-author. journal and doctoral student at the McGill Space Institute.
Of the 10 recurrent FRBs, only two were found at their point of origin: one in a dwarf galaxy and the other in a spiral galaxy.
More FRB can be detected
The FRB is a hot topic in the astronomical world, mainly because it is a relatively new discovery and the mechanism responsible is not understood.
"We think we understand what's in the cosmos," Kaspi said. "But the fast radio bursts were a complete surprise, nobody was waiting for them, no one had predicted them, really, it's the technological advances that have allowed us to see that, and I think it's really interesting that we still learn very basic things about what's happening in the universe. "
Because they release such intense energy, some theories suggest that the source is a neutron star, a small dense star left behind a supernova. Another theory suggests that it could be a magnetar, a star similar to a neutron star, but with an extremely powerful magnetic field.
While the known FRBs – apparent repeaters and non-repeaters – are supposed to come from other galaxies, one of the new ones detected seems to be closer than the others, perhaps even in our own galaxy. However, Chawla said that if it were in our galaxy, "it would be very surprising.
"Because we know a lot of neutron stars in our own galaxy that emit such pulses, but none of them has been found as far back at the edge of our galaxy."
CHIME has been quite successful in looking for these confusing objects, but the best news is that the telescope is not working at full power: it needs to be better calibrated. Once this is done, it is expected that more FRBs will be detected daily. And that means more data to provide other astrophysicists with the tools they need to unlock their mystery.
"I think the coming year will be really good for the FRB," Kaspi said. "Will we know the answer in a year? I do not know, I do not know, maybe, but I think we'll have made significant progress in a year."
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