Powerful bursts of radio waves emitted by a distant dwarf galaxy, which were discovered with the help of a massive telescope in China, bring scientists closer to solving what they called a “space mystery” that has lingered for years.
Since they were discovered in 2007, astronomers are struggling to figure out what causes phenomena called rapid radio bursts, which involve pulses of radio frequency electromagnetic radiation from places in our Milky Way and other galaxies. Radio waves have the longest wavelength in the electromagnetic spectrum.
Astronomers suspect that these bursts could be triggered by certain extreme objects. These may include: a neutron star, the compact collapsed core of a massive star that explodes as a supernova at the end of its life cycle; magnetar, a type of neutron star with an ultra strong magnetic field; and a black hole that cluttered up a neighboring star.
Researchers on Wednesday said they had discovered a fast radio emission or FRB, originating from a dwarf galaxy nearly 3 billion light-years from Earth. A light year is the distance that light travels in one year – 9.5 trillion km. The collective stellar mass of this galaxy is approximately one-2500th of that of our Milky Way.
The FRB was first spotted in 2019 with the help of the FAST telescope in the Chinese province of Guizhou, the world’s largest single-plate radio telescope, which has a signal reception area of 30 football fields. It was further studied using the Very Large Array telescope in New Mexico.
Aerial view shows a five-hundred-meter spherical telescope (FAST) in the remote Pingtang County in Guizhou Province in southwest China. (Liu Xu / Xinhua / Associated Press)
“We still call the rapid radio bursts a cosmic mystery, and rightly so,” said astrophysicist Di Li of the Chinese Academy of Sciences in Beijing, chief FAST scientist and co-author of the study, published in the journal Nature.
“Fast radio bursts are intense, brief flashes of radio light that are powerful enough to be seen from across the universe,” added Caltech astronomer and co-author Casey Lowe. “The explosion flashes in about a millisecond, much faster than the blink of an eye. Some FRB sources have been found to emit multiple bursts in what appears to be storms of activity, but others have been observed to erupt only once. “
Canadian connection
The newly described FRB is repetitive, which also features constant but weaker radio emissions between bursts. In other words, it always stays “on”. Most of the approximately 500 known FRBs do not recur. The new one is very similar to another, discovered in 2015 – by Canadian Paul Scholz, who at the time was a PhD student at McGill – this is the first FRB whose location has been determined.
Canada remains one of the main researchers of these mysterious signals. In 2017, the Canadian Hydrogen Intensity Mapping Experiment (CHIME) began work in the mountains of British Columbia at the Dominion Radio Astrophysics Observatory near the Penticton. One of its goals is to detect the FRB, as well as monitor pulsars, measure the expansion of the universe and help detect gravitational waves.
In its first year of operation, the telescope detected more than 500 FRB.
WATCH The CHIME telescope was discovered in BC
A new radio telescope has been discovered in British Columbia
Scientists hope CHIME, Canada’s largest radio telescope, will be a big step forward in unraveling the secrets of the universe
Lee noted that a number of hypotheses have been proposed to try to explain these outbreaks.
“The abundance of models reflects our lack of understanding of the FRB. Our work favors active repeaters that are born out of an extremely explosive event like a supernova. “These active repeaters are also young, as they should be seen shortly after birth,” Lee said.
Astronomers suspect that the newly described FRB is a “newborn”, still shrouded in dense material blown into space by the explosion of a supernova that left behind a neutron star. They said recurring outbreaks may be a feature of younger FRBs, perhaps dissipated over time.
Discoveries such as the newly described FRB can help scientists determine the cause of these radio outbreaks. Earlier, scientists were able to explain the cause of another mysterious phenomenon – extremely vigorous explosions, called gamma-ray bursts – such as the death of massive stars, merging neutron stars and magnetars.
“FRBs have quickly risen to become a great example of an astrophysical puzzle, just as gamma-ray bursts were decades ago,” Lo said.
“We know more and more about the phenomenon of where springs live, how often they burst, etc. However, we are still chasing this golden dimension, which will give us a definite answer to what causes them.”
Add Comment