They're called high-speed explosives or FRBs, and these strange, fleeting signals from space are shrouded in mystery. But thanks to Canada's largest radio telescope, astrophysicists are finding more of them in their search to learn what makes these objects flow.
The first FRB was discovered in 2007 by an astrophysicist and his student while passing in 2001 data collected from the Parkes Observatory in New South Wales, Australia. Since then, dozens more have been detected. As for what causes these signals, scientists are yet to learn.
But those brief signals that cross the universe – and only last a millisecond or so – were another surprise: some of them are repeated.
The first of these repeaters was discovered by McGill PhD student Paul Scholz in 2015. The second was discovered last January. And the list is getting longer.
In a new study, Presented in a letter to the Astrophysical Journal Letters and pre-printed on arXiv.org, a group of Canadian scientists reveal that the Canadian Hydrogen Intensity Mapping Telescope (CHIME) has detected eight more repetitive FRBs.
The findings are an important step to better understand what creates these powerful signals and where exactly they come from.
"The first biggest conclusion [from the paper] is that this is not an anomalous phenomenon. That's real, "said Victoria Caspi, an astrophysicist at McGill University and the Canadian Institute for Advanced Studies (CIFAR)." It just takes time and patience to find them. And two, it offers the ability to locate them and this is huge in the FRB field. "
The CHIME tool cannot be both sensitive and precise in its detection, which means that it cannot locate the signal. Instead, his job is to find as many as he can. Determining their exact location depends on other telescopes.
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"Finding eight sources like this is so important because it says we have a lot more recurring FRBs and can understand the environments and galaxies that these FRBs are in if we follow them with other telescopes," says Pragya Chaula, co-author of a PhD student and a PhD student at the McGill Space Institute.
Of the 10 recurring FRBs, only two have been traced to their point of origin: one is in a dwarf galaxy and the other is in a spiral galaxy.
More FRBs can be detected
FRG is a hot topic in the astronomical world, mostly because they are a relatively new discovery and the responsible mechanism is not understood.
"We think we understand what's in space," Caspi said. "But the rapid launch on the radio was a total surprise. No one expected them. No one predicted them. Indeed, technological advances have allowed us to see this. And I think it's really interesting that we are still learning a lot of basic things about what is happening." in the universe. "
Because they release so much intense energy, some theories suggest that the source is a neutron star, a small dense star left after a supernova. Another theory suggests that it could be a magnet, a star similar to a neutron star, but with an extremely powerful magnetic field.
While famous FRBs – both repeaters and visible non-repeaters – are thought to originate from other galaxies, one newly discovered appears to be closer than the others, perhaps even in our own galaxy. However, Chaula said that if it were found in our galaxy, "it would be very surprising.
"Because we know many neutron stars in our own galaxy that emit such pulses, but none have been seen to be found this far at the end of our galaxy."
CHIME is quite successful in finding these puzzling objects, but the even better news is that the telescope is not operating at full power: it still needs better calibration. Once this is done, it is expected that even more FRBs will be detected daily. And that means more data to give other astrophysicists the tools to solve their mystery.
"I think the coming year will be really good for FRBs," Caspi said. "Will we know the answer in a year? I don't know. I don't know. Maybe. But I think we'll make significant progress in a year."