WEBB TELESCOPE TRACES FARTHEST FAST RADIO BURST TO SMALL GALAXY

Astronomers have used the James Webb Space Telescope to identify the source galaxy of the most distant fast radio burst detected to date, according to a study published in the journal Science. The burst, named FRB 20240304B, was first detected in 2024 using the MeerKAT radio telescope array in South Africa, which pinpointed its position in the sky. Researchers say the signal travelled more than 10 billion light-years, more than doubling the previous distance record for such bursts. Webb's near-infrared instruments located the host galaxy, with measurements of the light's stretch indicating the burst occurred roughly 3 billion years after the Big Bang. The study's lead author, Manisha Caleb of the University of Sydney, worked with co-author Themiya Nanayakkara of the Sydney Institute for Astronomy on the research.

Fast radio bursts are brief flashes of radio waves from deep space, lasting only milliseconds but releasing energy comparable to what the sun emits over three days, according to the researchers. They were first identified in 2007, and thousands have been detected since, though their origins remain poorly understood. According to the study, the galaxy that produced FRB 20240304B was around 1,000 times smaller than expected, contained few elements beyond hydrogen and helium, and was undergoing active star formation. Earlier bursts have been traced to older, more massive star-forming galaxies, the researchers said. Ground-based telescopes initially found no visible galaxy at the burst's location, which the researchers said suggested it was too faint to detect without Webb's help.

The findings bear on competing theories about what causes fast radio bursts. One theory holds that they result from collisions between neutron stars, a process researchers say takes billions of years and would only occur in older galaxies. Caleb said the characteristics of the host galaxy made it "very unlikely" that this burst was produced by such a merger. Instead, the researchers say the evidence points towards a supernova explosion leaving behind a magnetar, a rare type of neutron star with an intense magnetic field, as the likely cause. The study was published on 8 October in Science.