Mysterious fast radio bursts are coming faster and faster, a boon for astronomers, says MIT researcher

Mysterious fast radio bursts are coming faster and faster, a boon for astronomers, says MIT researcher

The discovery of the three-second “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 into mysterious bursts of radio signals that have not been discoveries that 15 years ago.

Fast radio bursts are flashes of radio waves that usually last a few milliseconds. They are so powerful that they can be seen 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, however, reports from others were slow to arrive. In 2019, researchers reported in a review article in The Astronomy and Astrophysics Review, less than a hundred had been found, although researchers estimated that detectable bursts occurred once a minute somewhere in the sky.

The researchers got a big boost from the Canadian Hydrogen Intensity Mapping Experiment, a groundbreaking new Canadian radio telescope. CHIME, which started operating in 2018, is designed to pick up 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, it had detected more than 1,000, according to the CHIME website. “Such a high event rate promises major progress on this puzzling new astrophysical phenomenon,” the website said.

The latest discovery is a product of the CHIME/FRB (Fast Radio Burst) collaboration. MIT professor Kiyoshi Masui is a member 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 most durable fast radio burst. With nine regularly spaced signal peaks, spaced about 0.2 seconds apart, it had the clearest periodic pattern detected to date, MIT said.

The researchers suspect the signals could come from a radio pulsar or a magnetar, two types of neutron stars, which are the collapsed cores of massive stars.

Michilli said it’s difficult, but possible, to use multiple telescopes to triangulate and pinpoint the point in the sky where the signals are coming from. This has been done in about 15 cases so far and the emissions have been confirmed to originate from other galaxies.

CHIME, he said, plans to build more telescopes in the United States and Canada so that each of the fast radio bursts – currently several per day – can be located.

Scientists are looking to learn more in two areas, he said. They want to know where the signals are coming from. “That’s the first mystery, what produces them,” Michilli said.

They also want to analyze distortions in radio signals to find telltale clues about the characteristics of the plasma – the gaseous collection of atoms and ions in space – that the signals traveled through on their impossibly long journey to Earth.

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


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

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