Fast radio bursts (FRB) or Lorimer bursts have fascinated scientists since their first discovery in 2007. Fourteen years ago, David Narkevic, then a student at the University of West Virginia, made an amazing discovery.
While digging through old data from the Australian Parkes Observatory, he identified a very strong, very short signal from the Magellanic Clouds. Subsequent analyzes showed that this was of extragalactic origin and that the diameter of the emission source measured no more than 10 milliseconds of light.
More similar signals were discovered in the early 2010s. But it wasn’t until 2015 that the mystery was solved (at least in part) thanks to the discovery of a source of repeated rapid radio bursts called FRB 121102.
Phenomena difficult to study
However, because of their rapidity, these outbreaks are very difficult to study and track. Every shock is extremely strong and generates more energy than our sun produces in a whole year. Thanks to NASA’s Hubble Space Telescope, scientists have just taken an important new step in studying FRBs. As CNN claims, astronomers have managed to track the location of eight high-speed radio bursts. These came from various spiral galaxies, which are between about 400 million and 9 billion light years, according to the news website fredzone.org.
An unprecedented study
To achieve this discovery, the researchers relied on a combination of visible light, ultraviolet, and near infrared imaging. “This is the first high-resolution view of an FRB population,” said lead author Alexandra Mannings, a PhD student in astronomy and astrophysics at the University of California, Santa Cruz. Note that the results of this research should appear soon in The Astrophysical Journal as they have been validated by colleagues.
The two images on the left show the full Hubble snapshots of each galaxy. The two digitally enhanced images on the right show the spiral structure of each galaxy in greater detail. Photo credits: NASA, ESA, Alexandra Mannings (uc santa cruz), Wen-Fai Fong (northwest) Image editing: Alyssa Pagan (stsci)
Signals from magnetars?
It used to be believed that rapid radio bursts could be due to explosions of young stars or mergers of neutron stars. However, Mannings and Wen-fai Fong, co-authors of the study and assistant professor of physics and astronomy at Northwestern University’s Weinberg College of Arts and Sciences, say the signals came from the spiral arms of galaxies. “Since spiral arms are signs of star formation, this came as a surprise and provided an important indication that FRBs must be correlated with star formation,” said Fong.
In addition, the researchers found that the radio flashes came from “golden loop” regions, which suggests that the stars responsible for them may not be too young or too old. Another hypothesis by the team is that the main cause of the radio outbursts could be magnetar explosions.
These are supermassive neutron stars with an extremely intense magnetic field that cause high-energy electromagnetic radiation. “Because of their strong magnetic fields, magnetars are quite unpredictable (…) In this case, FRBs are believed to have originated from the eruptions of a young magnetar,” Fong said, reports CBS News.