Scientists at the Massachusetts Institute of Technology on Wednesday said they had catalogued more than 500 fast radio bursts in the first year of using the CHIME telescope, nearly four times more than previously detected. The findings could help in mapping out the universe, they said.
CHIME, short for the Canadian Hydrogen Intensity Mapping Experiment, detected 535 bursts in its first year of operation — 2018-19 — after previous telescopes had only been able to find 140 since fast radio bursts were first discovered in 2007, MIT said in a statement.
Comprised of four massive radio antennas, CHIME is a stationary telescope that uses a digital signal processor to comb through all the data it takes in. In the past, fast radio bursts have been detected by pointing a large dish at a portion of the sky, while CHIME is able to take in data from half the sky as earth rotates, the statement said.
Calvin Leung, an MIT graduate student, said the fast radio bursts act as “lighthouses” for researchers attempting to sketch out the universe.
“You can use these bursts to really map out the universe,” Leung said in a telephone interview Wednesday afternoon. “They’re kind of like lighthouses or sonar pings and for the very first time we’ve shown that we can detect them in large enough quantities that you can really use them to make statements like, ‘Oh, the universe is expanding at this rate,’ or ‘This is how much matter there is in the whole universe.’”
The bursts are dubbed fast radio bursts because they flash just for an instant. They are on the same wavelength as some cellphone company signals, Leung said. Researchers believe they emanate from “an exotic class of star” known as magnetars, which are “essentially giant balls of neutrons” created from the remnants of collapsed larger stars. Those neutron stars are responsible for “a lot of the violent phenomena” in the universe, Leung said..
Fast radio bursts carry with them a “fingerprint,” Leung said, and that fingerprint allows researchers to learn more about the burst itself - and which areas of space it has passed through.
“The actual signal itself carries imprints of all the space and all the matter it’s traveled through,” he said. “For example, if you have a burst that’s really close to us, it won’t get smeared out. But if you have a burst that’s far away, it’ll be smeared out by quite a lot. We’re actually able to measure that amount of smearing that the burst suffers on its way to earth, and the amount of smearing tells us what it’s traveled through.”
Leung said a sonar ping bounces off of a surface enabling researchers to figure out what that surface looks like. A similar thing happens with fast radio bursts — the difference being that the ping is “coming from the universe itself and it carries imprints of what happens to it as it comes to earth.”
Moving forward, researchers plan to construct several more “halfpipe” telescopes to work in tandem with CHIME to help provide a clearer picture of which galaxy the fast radio bursts are located in, something Leung described as a “weak point” for CHIME right now.
“By processing the data from all those telescopes together, you can use those kind of like a triangulation network to really pinpoint which galaxy hosts each of these mysterious things,” he said. “Let’s say you detect a fast radio burst and it’s really, really bright. There are two reasons why it could be really bright. It could be an extremely powerful burst and that makes it really, really interesting. But it could just be a totally normal burst, that’s really, really close by to you. And right now, we don’t have a great way to distinguish between those two possibilities.”