The mysterious fast radio bursts are coming in thick and fast, in boon for astronomers

The mysterious fast radio bursts are coming in thick and fast, in boon for astronomers

The discovery of the three-second-long “fast radio burst,” reported last week by Michilli and other researchers in the journal Nature, was the latest addition to the growing body of research about the mysterious bursts of radio signals that were discovered only 15 years ago.

Fast radio bursts are flashes of radio waves that typically last milliseconds. They are so powerful 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 of others were slow to come in. As of 2019, researchers reported in a review article in The Astronomy and Astrophysics Review, less than a hundred had been found, even though researchers estimated that detectable bursts were occurring once every minute somewhere on the sky.

Researchers got a big boost from the Canadian Hydrogen Intensity Mapping Experiment, a revolutionary new Canadian radio telescope. CHIME, which began operating in 2018, is designed to pick up radio waves emitted by hydrogen in the earliest stages of the universe. At the same time, it is an excellent detector of fast radio bursts. By mid-2020, it had detected well over 1,000 of them, according to the CHIME website. “So high an event rate promises major progress on this puzzling new astrophysical phenomenon,” the website said.

Jason Hessels, a professor at the University of Amsterdam and chief astronomer at the Netherlands Institute for Radio Astronomy, said CHIME has been “without question” a boon to radio astronomers studying fast radio bursts.

“CHIME is the world’s most successful telescope for discovering new fast radio bursts. This is because it can scan the sky 1,000 times faster than most other telescopes and because it is attached to a giant supercomputer that can process the huge data stream in near real time,” said Hessels, who is not affiliated with CHIME.

Hessels noted that there are other radio telescopes that are also studying fast radio bursts, including the ASKAP telescope in Australia and the European VLBI Network (EVN), a globally distributed set of telescopes that his own team uses to pinpoint fast radio bursts.

The latest discovery was a product of the CHIME/FRB (Fast Radio Burst) Collaboration. MIT Professor Kiyoshi Masui is one of the members of the collaboration, and Michilli was studying the 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.

Researchers suspect the signals could be coming from either a radio pulsar or a magnetar, two types of neutron stars, which are the collapsed cores of massive stars.

Michilli said that it’s challenging, but possible, to use multiple telescopes to triangulate and locate the point on the sky where the signals are coming from. It’s been done in about 15 cases so far and it has been confirmed that the emissions were coming from other galaxies.

CHIME, he said, is planning to build more telescopes in the United States and Canada so that every one of the fast radio bursts – currently several a day – can be located.

Scientists are looking to learn more in two areas, he said. They want to know how the signals originate. “This is the first mystery, what produces these,” said Michilli.

They also want to analyze distortions in the radio signals for telltale clues to the characteristics of the plasma – the gas-like collection of atoms and ions in space – that the signals traveled through on their incredibly long journey to Earth.

Analyzing fast radio bursts can help researchers “understand what makes up those seemingly empty spaces between galaxies,” said Emily Petroff, a postdoctoral fellow at McGill University and the University of Amsterdam who is the CHIME/FRB (Fast Radio Burst) Collaboration project manager.

The signals could, in effect, be “probes to investigate the universe,” Michilli said.


Martin Finucane can be reached at martin.finucane@globe.com.

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