Radio Bursts could be erupting in the universe every second

Based on the analysis of FRB 121102, astronomers conclude that these bursts could be happening continuously all over the sky


This filamentary structure of galaxies exists across the entire sky, and the bright blue points represent the FRBs that could accumulate in a radio exposure lasting for a few minutes. Image credit: M. Weiss/CfA

Two astronomers from the Harvard-Smithsonian Centre for Astrophysics (CfA) have latterly extrapolated their research of the elusive Fast Radio Burst (FRB) of FRB 121102. The research has led astronomers to estimate that FRBs should occur over the entire observable universe, in fact at least one burst should be going off somewhere each second.

“If we are right about such a high rate of FRBs happening at any given time, you can imagine the sky is filled with flashes like paparazzi taking photos of a celebrity,” says Anastasia Fialkov of the CfA. “Instead of the light we can see with our eyes, these flashes come in radio waves.”

FRBs have been a mystery ever since their discovery in 2001, as astronomers don’t know where they came from or what causes their intense bursts of radio emission. Fialkov and Avi Loeb have since studied FRB 121102 profusely, as it is the most detailed FRB since its discovery in 2002. For this theory to exist, Fialkov and Loeb have assumed that FRB 121102 is typical among the universe and projected how many FRBs would exist across the sky.

Neutron stars, depicted here by an artist, could be the source of FRBs. Image credit: NASA’s Goddard Space Flight Centre/S. Wiessinger

“In the time it takes you to drink a cup of coffee, hundreds of FRBs may have gone off somewhere in the universe,” explains Avi Loeb. “If we can study even a fraction of those well enough, we should be able to unravel their origin.”

Although the origins of FRBs are still unknown, the best explanation so far is that they are by-products of young, rapidly spinning neutron stars and their concentrated magnetic fields. What Fialkov and Loeb have also stated is that FRBs can still be used to detail the evolution of the universe, regardless of the lack of knowledge out their origins. As FRBs are such distance objects – for example, FRB 121102 is located 3 billion light years away – they can be used to trace what broke down the “fog” of hydrogen atoms in the early universe. As soon after the Big Bang, it is thought among many astronomers that the temperature cooled throughout the universe, thus ushering in the era of the first stars ever made. The new star’s ultraviolet radiation broke down this primordial fog of hydrogen into free electrons and protons in a process called ‘reionisation’.

“FRBs are like incredibly powerful flashlights that we think can penetrate this fog and be seen over vast distances,” explains Fialkov. “This could allow us to study the ‘dawn’ of the universe in a new way.”

The CfA astronomers also examine how new telescopes, such as the Canadian Hydrogen Intensity Mapping Experiment (CHIME), could be potentially vital for detecting FRBs. However, the detecting of bursts in this case would be dependant on their spectrum, because if a new FRB has a different spectrum to FRB 121102, CHIME will struggle to detect many FRBs this way.

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