Fast radio bursts (FRBs) are mysterious flashes of cosmic energy that erupt across the sky every day. They release as much energy in milliseconds as the sun does in a day. Scientists have often had to rely on luck to observe them, let alone pinpoint their origins or causes.
Astronomers led by Kritti Sharma at the California Institute of Technology suggest that these energy-packed light flashes tend to occur in massive, star-forming galaxies. These findings also shed light on the formation of powerful, long-dead stars known as magnetars. Magnetars might form from the cosmic fusions of two stars, providing one potential formation pathway for these mysterious objects.
“Very little is known about what causes the formation of magnetars upon the death of massive stars,” Sharma said in a recent news release. “Our work helps to answer this question.”
By analyzing the home galaxies of 30 FRBs recorded by California’s Deep Synoptic Array-110, Sharma and her colleagues found that the bursts originated in massive, star-forming galaxies rich in “metals” — astronomer-speak for any element heavier than hydrogen and helium.
Massive galaxies and mysterious FRBs
Such metal-rich environments may be conducive to the formation of magnetars, which are leading candidates for producing FRBs. Magnetars, a type of neutron star, may be the explosive remnants of stellar mergers, rather than the result of massive stars collapsing and exploding as supernovae, since these phenomena originate in different types of environments, the team suggested in a study published in the journal Nature. Metal-rich stars residing in pairs within such galaxies tend to become less compact as they evolve, accelerating the transfer of mass between them and effectively initiating the timeline for a stellar merger.
The surviving star, usually the larger of the two, is rejuvenated by burning the fuel accreted from its companion, leading to amplified magnetic fields that are hundreds of trillions of times stronger than Earth’s — a magnetar. This scenario could also explain the occasional detection of FRBs in regions with old stars, as binary star systems typically live longer compared to isolated magnetars. Other questions linger about the nature of FRBs, including why a handful seem to go off multiple times a day while others flash only once.
“We have no idea what’s causing them,” Ayush Pandhi of the University of Toronto in Canada told Astronomy.com. “It’s one of the big mysteries in astronomy right now.”
Cameron is a highly regarded contributor in the rapidly evolving fields of artificial intelligence (AI) and machine learning. His articles delve into the theoretical underpinnings of AI, the practical applications of machine learning across industries, ethical considerations of autonomous systems, and the societal impacts of these disruptive technologies.
