Fast radio burst, or FRB, is an intense explosion of radio waves lasting up to a few milliseconds from an unknown source. The first FRB was discovered in 2007, and since then hundreds of these cosmic flashes have been detected from different and distant points in the universe.
Many FRB emit ultra-bright radio waves that last only a few milliseconds at most before completely fading and are known to have about 10% repetition and pattern.
This telescope, in operation since 2018, constantly monitors the sky and in addition to rapid radio explosions, it is sensitive to radio waves emitted by hydrogen far away from the universe.
Astronomers using CHIME discovered something on December 21, 2019 that immediately caught their attention: a rapid radio explosion “strange in many ways” according to postdoctoral researcher Daniel Mitchell. At the Cavalli Institute for Astrophysics and Space Research at the Massachusetts Institute of Technology.
The signal, called FRB 20191221A, lasts up to three seconds, about 1,000 times faster than a normal fast radio explosion.
Michelle was observing data from Chim when the explosion occurred. The signal is by far the longest lasting radio wave.
“It was amazing,” Mitchell said. “It wasn’t too long and lasted about three seconds, but there were periodic peaks that were extraordinarily precise, with each millisecond – boom, boom, boom – sounding like a heartbeat. This is the first time that the same signal is periodic.”
Although FRB 20191221A has not yet been replicated, “the signal is made up of a series of successive peaks that we separated by about 0.2 seconds,” he said in an email.
Michelle said the research team did not know exactly where the explosion originated from the galaxy and that the estimate, even a billion light-years away, was “extremely uncertain.” Although CHIME is interested in exploring a lot of radio waves, they are not very good at locating their sources.
However, CHIME is being built as part of a project where additional telescopes, currently under construction, will be able to observe together and be able to triangle radio explosions in specific galaxies, he said.
However, it does provide clues as to where the signal came from and what could have caused it.
“CHIME has now identified many FRBs with different features,” Michelle said. “We have seen some living in very turbulent clouds, others living in a clean environment. From the properties of this new signal, we can say that there are plasma clouds around this source which must be very turbulent. A
When the researchers analyzed FRB 20191221A, the signal was similar to the emission from two different types of neutron stars, or dense residues after the death of a giant star, called radio and magnetic pulsars.
Magnets are neutron stars with incredibly strong magnetic fields, while radio pulsars emit radio waves that vibrate as the neutron star rotates. Two stellar objects make a signal like the flashing beam of a lighthouse.
Rapid radio explosions seem to be a million times brighter than this broadcast. “We think this new signal could be a magnet or a pulsar on doping,” Michelle said.
The research team will continue to use CHIME to monitor the sky for more signals from this radio explosion, as well as others with the same 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 could be the cause of this extreme signal that we have never seen before and how we can use this signal to study the universe,” Michelle said. “Future telescopes promise to detect thousands of FRBs per month, in which case we can find more of these periodic signals.”