Fast Radio Bursts, or FRBs, are intense eruptions of radio waves that last up to a few milliseconds from unknown sources. The first FRB was discovered in 2007, and since then hundreds of these cosmic glimpses have been discovered from various and distant points across the universe.
Many FRBs emit ultra-light radio waves that last a maximum of a few milliseconds before fading completely, and about 10% of them are known to repeat and have patterns.
This telescope, which has been in operation since 2018, constantly monitors the sky, and in addition to rapid radio eruptions, it is sensitive to radio waves emitted by hydrogen far out in the universe.
Astronomers using CHIME discovered something on December 21, 2019, that immediately caught their attention: a rapid radio eruption that was “in many ways strange,” according to postdoc researcher Danielle Mitchell. at the Kavli Institute for Astrophysics and Space Research at the Massachusetts Institute of Technology.
The signal, called FRB 20191221A, lasted up to three seconds, about 1,000 times longer than typical fast radio bursts.
Michelli was monitoring data received from CHIME when the explosion occurred. The signal is the longest fast radio wave to date.
“It was amazing,” Mitchell said. “It was not very long and lasted about three seconds, but there were periodic peaks that were remarkably accurate, where every millisecond – boom, boom, boom – sounded like a heartbeat. This is the first time that the same signal is periodic. . »«
While the FRB 20191221A has not yet been replicated, “the signal is formed by a series of consecutive peaks that we found separated by about 0.2 seconds,” he said in an email.
Micheli said the research team does not know the exact galaxy the explosion originated from, and even the estimate of a billion light-years away is “very uncertain”. While CHIME are willing to search for lots of radio waves, they are not very good at locating their places of origin.
However, CHIME is being developed as part of a project where additional telescopes currently under construction will together monitor and be able to triangulate radio outbursts to specific galaxies, he said.
But the signal contains a clue as to where it came from and what could have caused it.
“CHIME has now discovered many FRBs with different properties,” Micheli said. “We have seen some live inside very turbulent clouds, while others appear to be in clean surroundings. Based on the properties of this new signal, we can say that around this source there is a cloud of plasma, which must be very turbulent. »
When the researchers analyzed FRB 20191221A, the signal resembled emissions from two different types of neutron stars or the dense remnants after the death of a giant star, called radio and magnetic pulsars.
Magnetars are neutron stars with incredibly strong magnetic fields, while radio pulsars emit radio waves that appear to pulsate as the neutron star rotates. The two star objects create a signal similar to the flashing beam from a lighthouse.
The fast radio eruption appears to be a million times brighter than these broadcasts. “We think this new signal could be a magnetar or a pulsar on doping,” Micheli said.
The research team will continue to use CHIME to monitor the sky for multiple signals from this radio burst, as well as others with a similar periodic signal. The frequency of radio waves and their evolution can be used to help astronomers learn more about the rate at which the universe is expanding.
“This discovery raises the question of what can cause this extreme signal that we have never seen before and how we can use this signal to study the universe,” Micheli said. “Future telescopes promise to detect thousands of FRBs a month, in which case we can find more of these periodic signals.”