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 the mysterious bursts of radio signals discovered just 15 years ago.
Fast radio bursts are flashes of radio waves that typically 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.)
However, after the first report in 2007, it was slow to receive reports from others. As of 2019, researchers reported in a review article in The Astronomy and Astrophysics Review that fewer than a hundred had been found, although scientists estimated that detectable bursts occurred once every minute somewhere in the sky.
Scientists 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 capture radio waves emitted by hydrogen in the earliest stages of the universe. At the same time, it is an excellent detector for fast radio bursts. By mid-2020, it had discovered well over 1,000 of them, according to the CHIME website. “Such a high event rate promises great progress with this puzzling new astrophysical phenomenon,” the website says.
The latest discovery was a product of the CHIME/FRB (Fast Radio Burst) Collaborative. MIT professor Kiyoshi Masui is a member of the collaboration, and Michilli studied the CHIME data as one of the researchers in Masui’s group.
The burst, designated FRB 20191221A, is the fastest and longest-lasting radio burst. With nine regularly spaced signal peaks, about 0.2 seconds apart, it had the clearest periodic pattern discovered to date, MIT said.
Scientists suspect that the signals may come from either a radio pulsar or a magnetar, two types of neutron stars, which are the collapsed cores of massive stars.
Michilli said it is challenging, but possible, to use multiple telescopes to triangulate and locate the point in the sky where the signals are coming from. It has been done in about 15 cases so far, and it has been confirmed that the emissions came 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 a day — can be located.
Researchers are looking to learn more in two areas, he said. They want to know how the signals occur. “This is the first mystery, what produces these,” Michilli said.
They also want to analyze distortions in the radio signals for clues to the properties 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.
In that sense, the signals could be “probes to probe the universe,” Michilli said.
Martin Finucane can be reached at email@example.com.