Astronomers at the Massachusetts Institute of Technology (MIT) and universities in Canada and the United States say they have detected a radio signal from a distant galaxy that flashes repeatedly.
In a paper published in the Journal of Nature, co-authored by members of the Canadian Hydrogen Intensity Mapping Experiment (CHIME)/FRB Collaboration, scientists said a fast radio burst (FRB) located several billion light-years from Earth.
CHIME is an interferometric radio telescope at the Dominion Astrophysical Observatory in British Columbia, Canada. It is designed to detect radio waves emitted by hydrogen in the early stages of the universe, and it has detected hundreds of FRBs.
FRBs are millisecond-long flashes of radio waves that can be seen at distances of billions of light years. FRB was first discovered 15 years ago; Hundreds of similar radio flashes have been detected, although the majority of the FRBs observed were one-off.
What exactly is the source of the FRB, named FRB 20191221A, remains a mystery.
Astronomers hypothesize that the repeating signal could come from a magnetar or radio pulsar – types of neutron stars – “on steroids”. Neutron stars are the dense and collapsed cores of giant stars.
However, the duration of FRB 20191221A is the most well known.
The wireless signal, captured in December 2019, lasts up to three seconds, or about 1,000 times longer than the average FRB.
“It was quite unusual,” Danielle Micheli, a postdoctoral researcher at the Kavli Institute for Astrophysics and Space Research at MIT, recalled in a statement. “It wasn’t very long, lasted about three seconds, but there were periodic peaks that were remarkably accurate, emitting every millisecond—boom, boom, boom—like a heartbeat. This is the first time the signal itself has been periodic.”
It is currently the longest persistent FRB with the clearest periodic pattern to date and the team has detected bursts of radio waves that repeat every 0.2 seconds in a clear pattern.
Long (approx [3-second]) duration and nine or more components that make up the pulse profile render this source far into the FRB. Such a short periodicity provides strong evidence for the origin of the neutron stellar event. Furthermore, our finding favors emissions originating from the magnetosphere of a neutron star, as opposed to emission regions located far from the star, as predicted by some models.”
In addition, FRB 20191221A appears to be a million times brighter than radio emissions from our pulsars and magnetospheres.
“CHIME has now discovered many FRBs with different properties,” Micheli noted. “We have seen some live inside very turbulent clouds, while others appear to be in clean environments. From the characteristics of this new signal, we can say that around this source, there is a cloud of plasma that must be very turbulent.”
The team aims to detect more signals from this source, which MIT said in a version that could be used as an “astrophysical clock” — and perhaps even measure the expansion rate of the universe.
Future telescopes promise to detect thousands of FRBs per month, Micheli said, which could lead to “more of these periodic signals being detected.”
The announcement comes after the release of the first images from the James Webb Space Telescope, which dates back billions of years.