Researchers have linked the origins of fast radio bursts to magnetars, highly magnetized neutron stars, which often arise from the mergers of massive stars in star-forming galaxies.
By utilizing the Deep Synoptic Array-110, they’ve localized 70 FRBs, discovering that these bursts are more frequent in massive, metal-rich galaxies. This suggests that the environmental conditions conducive to FRB occurrence are also ideal for magnetar formation.
Unveiling the Mystery of Fast Radio Bursts
Since their discovery in 2007, fast radio bursts (FRBs)—extremely energetic pulses of radio waves—have been repeatedly observed, sparking an intense search by astronomers to identify their origins. Hundreds of these bursts have now been confirmed, and scientists believe they are likely triggered by highly magnetized neutron stars, known as magnetars. Neutron stars, remnants of massive stars that have exploded in supernovae, are among the densest objects in the universe. A critical piece of evidence supporting the magnetar theory came when a magnetar in our own galaxy erupted, and several observatories, including Caltech’s STARE2 project (Survey for Transient Astronomical Radio Emission 2), captured the event in real time.
In new research published in Nature, a Caltech-led team has pinpointed where FRBs are most likely to occur: in massive, star-forming galaxies rather than in smaller, low-mass ones. This discovery offers fresh insights into how magnetars might form. The study suggests that these unusual dead stars, with magnetic fields a staggering 100 trillion times stronger than Earth’s, often arise when two stars merge and subsequently explode as a supernova. Previously, it was unclear if magnetars formed in this way—from the explosion of two merging stars—or if they could also form from the explosion of a single star.
Insights on Magnetar Formation
“The immense power output of magnetars makes them some of the most fascinating and extreme objects in the universe,” says Kritti Sharma, lead author of the new study and a graduate student working with Vikram Ravi, an assistant professor of astronomy at Caltech. “Very little is known about what causes the formation of magnetars upon the death of massive stars. Our work helps to answer this question.”
The project began with a search for FRBs using the Deep Synoptic Array-110 (DSA-110), a Caltech project funded by the National Science Foundation and based at the Owens Valley Radio Observatory near Bishop, California. To date, the sprawling radio array has detected and localized 70 FRBs to their specific galaxy of origin (only 23 other FRBs have been localized by other telescopes). In the current study, the researchers analyzed 30 of these localized FRBs.
