The discovery of the three-second “fast radio burst”, which Mitchell and other researchers reported in the journal Nature last week, is the latest addition to a growing body of research on mysterious bursts of radio signals that have only been detected 15 years ago.
Rapid radio bursts are flashes of radio waves that usually last for milliseconds. They are so powerful that they can be observed billions of light years away. (A light year is the distance light can travel in a year, or about 6 trillion miles.)
After the first report in 2007, though, reports for others were slow to come in. As of 2019, fewer than a hundred have been found, researchers reported in a review article in The Astronomy and Astrophysics, although the researchers estimated that the detectable bursts were occurring once every minute somewhere in the sky.
Researchers have received a major boost from the Canadian Hydrogen Density Mapping Experiment, a revolutionary new Canadian radio telescope. CHIME, which began operating in 2018, is designed to capture radio waves emitted by hydrogen in the early stages of the universe. At the same time, it is an excellent detector of fast radio bursts. By mid-2020, he had discovered more than 1,000 of them, according to the CHIME website. “The very high event rate promises significant progress in this puzzling new astrophysical phenomenon,” the site said.
The latest discovery was a product of the collaborative CHIME/FRB (Fast Radio Burst) collaboration. Professor Kiyoshi Masui at MIT is a member of the cooperative, and Michilli was studying CHIME data as one of the researchers in Masui’s group.
The Burst, designated FRB 20191221A, is the longest-lasting fast radio burst. With nine regularly spaced signal peaks, about 0.2 seconds apart, it had the clearest periodic pattern detected to date, MIT said.
The researchers believe the signals could come from a radio pulsar or a magnetar, which are two types of neutron stars, the collapsing cores of massive stars.
It’s difficult, but possible, Micheli said, to use multiple telescopes to triangulate and locate the point in the sky from which the signals are coming. This has been done in about 15 cases so far and it has been confirmed that the emissions were coming from other galaxies.
He said CHIME plans to build more telescopes in the US and Canada so that all the fast radio bursts can be located – currently several per day.
He said scientists are looking to learn more in two areas. They want to know how the signals originate. “That’s the number one puzzle, what does it produce,” said Micheli.
They also want to analyze the distortions in radio signals for telltale clues to the properties of plasmas – the gas-like collection of atoms and ions in space – with which the signals traveled on their incredibly long journey back to Earth.
The signals, in this sense, could be “sensors to examine the universe,” Micheli said.
Martin Finucane can be reached at [email protected]