Astronomers using the James Webb Space Telescope have pinpointed the host galaxy of the most distant fast radio burst ever detected. The burst, FRB 20240304B, was first caught by the MeerKAT radio telescope array in South Africa on March 4, 2024, and its radio signal suggested it came from extremely far away.

Webb's NIRCam camera found a faint galaxy at exactly the right position, and its NIRSpec spectrograph measured a redshift of 2.148, placing the burst just 3 billion years after the Big Bang. The result was published on October 8, 2026, in the journal Science, led by Manisha Caleb of the University of Sydney.

The surprise is the host itself. Most fast radio burst hosts are massive star-forming galaxies, but this one is a small dwarf galaxy actively forming stars, about 1,000 times less massive than astronomers expected. That is why ground-based telescopes, including Keck, could not see it at all, and only Webb's infrared eyes could pick it out.

The discovery strengthens the case that fast radio bursts come from magnetars, young, highly magnetic neutron stars. A small, young, star-forming dwarf galaxy is exactly the kind of place where a magnetar would be born, and the result argues against models that need long-lived binary mergers.

The burst's signal also carries the imprint of two cosmic structures it passed through on its way to Earth: a previously unknown galaxy cluster at redshift 0.3, about 3.5 billion light-years away, and the nearby Virgo Cluster, about 54 million light-years away. The team estimates MeerKAT could localise several bursts per year at redshift greater than 1.0, meaning Webb will have plenty more distant bursts to chase.