Where do fast radio bursts come from? Astronomers connect mysterious eruptions with huge galaxies

On November 9, 2024By Pranco

Every day, thousands of mysterious flashes of cosmic energy known as fast radio bursts (FRBs) erupt in the sky invisible to the human eye, releasing as much energy in milliseconds as the sun does in a day.

Due to their ephemeral nature, scientists often had to rely on luck to make observations FRBslet alone determine where they come from or what causes them to behave the way they do.

Now astronomers led by Kritti Sharma of the California Institute of Technology argue that such high-energy flashes of light often occur in massive star-forming regions. galaxies of powerful outbursts from rare, long-dead stars known as magnetars. These findings also indicate, according to the researchers, that magnetars themselves are cosmic mergers of two stars, establishing one possible formation path for the mysterious objects.

“Very little is known about what causes the formation of magnetars after the death of massifs stars,” Sharma said in one recent press release. “Our work helps answer this question.”

By analyzing the home galaxies of 30 FRBs recorded by the Deep Synoptic Array-110 in California, Sharma and her colleagues found that the outbursts originated in massive, star-forming galaxies that are rich in “metals” – astronomers speak for any element that is heavier than hydrogen and helium. . Such metal-rich environments could be conducive to the formation of magnetars, which the researchers say are prime candidates for the production of FRBs.

Magnetars, sort of neutron starcould be the explosive remnants of stellar mergers, rather than the result of massive stars collapsing and exploding as supernovasbecause the phenomena originate in different types of environments, the team suggested in a paper published Wednesday (Nov. 6) in the journal Nature.

Metal-rich stars found in pairs in such galaxies tend to become less compact as they evolve, speeding up the transfer of mass between them and effectively setting in motion the timeline for a stellar merger, the researchers say. The surviving star, usually the larger of the two, is rejuvenated by burning the fuel of its companion, leading to amplified magnetic fields hundreds of trillions of times stronger than Earth’s: a magnetar.

This scenario could also explain the occasional detection of FRBs in regions of old stars, as binary star systems tend to be longer-lived compared to isolated magnetars. This is reported by Natuurnieuws.

Other questions linger about the nature of FRBs, including why a handful seem to go off several times a day, while others flash only once.

“We have no idea what causes them,” said Ayush Pandhi of the University of Toronto in Canada Astronomy.com. “It’s one of the great mysteries in astronomy right now.”