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A mysterious radio burst with a pattern similar to a heartbeat has been detected in space.
Astronomers estimate that the signal came from a galaxy about a billion light-years away, but the exact location and cause of the outburst is unknown. A study detailing the findings published Wednesday in the journal Nature.
Fast radio bursts, or FRBs, are intense bursts of radio waves lasting milliseconds with unknown origins. The first FRB was discovered in 2007, and since then hundreds of these fast cosmic flashes have been detected coming from various distant points throughout the universe.
Many FRBs emit super-bright radio waves that last only a few milliseconds at most before fading away entirely, and about 10% of them are known to be repeating and patterned.
Fast radio bursts are so fast and unexpected that they are difficult to observe.
One resource used to detect them is a radio telescope called the Canadian Hydrogen Intensity Mapping Experiment, or CHIME, at the Dominion Radio Astrophysical Observatory in British Columbia. Canada.
This telescope, in operation since 2018, constantly observes the sky and, in addition to fast radio bursts, is sensitive to radio waves emitted by distant hydrogen in the universe.
Astronomers using CHIME detected something on December 21, 2019, that immediately caught their attention: a fast radio burst that was “peculiar in many ways,” according to Daniele Michilli, a postdoctoral researcher. at the Kavli Institute for Astrophysics and Space Research at the Massachusetts Institute of Technology.
The signal, named FRB 20191221A, lasted up to three seconds, about 1,000 times longer than typical fast radio bursts.
Michilli was monitoring the data coming from CHIME when the explosion occurred. The signal is the longest lasting fast radio burst to date.
“It was unusual,” Michilli said. “Not only was it very long, lasting about three seconds, but there were periodic spikes that were remarkably accurate, giving every split second, boom, boom, boom, like a heartbeat. This is the first time that the signal itself is periodic.”
While FRB 20191221A has yet to repeat itself, “the signal is made up of a train of consecutive spikes that we found separated by ~0.2 seconds,” he said in an email.
The research team doesn’t know the exact galaxy in which the outburst originated, and even the estimated distance of a billion light-years is “highly uncertain,” Michilli said. While CHIME is good at looking for bursts of radio waves, it’s not as good at locating their points of origin.
However, CHIME is being upgraded through a project in which additional telescopes, currently under construction, will observe together and be able to triangulate radio bursts to specific galaxies, he said.
But the signal contains clues as to where it came from and what might have caused it.
“CHIME has now detected many FRBs with different properties,” said Michilli. “We have seen some that live inside clouds that are very turbulent, while others appear to be in clean environments. From the properties of this new signal, we can tell that around this source there is a cloud of plasma that must be extremely turbulent.”
When the researchers analyzed FRB 20191221A, the signal was similar to emissions released by two different types of neutron stars, or the dense remnants after a giant star dies, called radio pulsars and magnetars.
Magnetars are neutron stars with incredibly powerful magnetic fields, while radio pulsars emit radio waves that appear to pulse as the neutron star rotates. Both stellar objects create a signal similar to the flashing beam of a lighthouse.
The fast radio burst appears to be more than a million times brighter than these emissions. “We think this new signal could be a magnetar or pulsar on steroids,” Michilli said.
The research team will continue to use CHIME to monitor the skies for more signals from this radio burst, as well as others with a similar periodic signal. The frequency of radio waves and how they change could be used to help astronomers learn more about the expansion rate of the universe.
“This detection raises the question of what could cause this extreme signal that we have never seen before and how we can use this signal to study the universe,” Michilli said. “Future telescopes promise to discover thousands of FRBs a month, and by that time we may find many more of these periodic signals.”
