Webb Finds the Tiny Host Galaxy of the Most Distant Fast Radio Burst
Webb traced FRB 20240304B to a young dwarf galaxy 3 billion years after the Big Bang, evidence that some fast radio bursts come from magnetars.
The James Webb Space Telescope has found the home galaxy of FRB 20240304B, the most distant fast radio burst traced to its host so far. A team led by Manisha Caleb of the University of Sydney published the result in Science, and ESA/Webb announced it on October 8, 2026. The host is a small, young dwarf galaxy seen about 3 billion years after the Big Bang.
Fast radio bursts (FRBs) are flashes of radio waves that last a few thousandths of a second. This one was caught on March 4, 2024 by the MeerTRAP team using the MeerKAT radio telescope. Webb’s NIRCam camera then picked out the faint host, and its NIRSpec spectrograph measured a redshift of 2.148, which places the galaxy in “cosmic noon”, the era when the universe was forming stars at its busiest.
The galaxy is about 1,000 times less massive than expected for an FRB host, and its star formation rate suggests most of its stars formed within roughly 30 million years. That short gap between star birth and the burst is the key clue. It favors young, highly magnetized neutron stars, called magnetars, over mergers of neutron stars, which take far longer to happen after stars form.
FRBs were discovered in 2007 and their origin is still debated. One record-distance burst is evidence that at least some come from young magnetars, not proof that all of them do. For more on how stars end up as neutron stars, see our guide to stars.
What to watch next: more distant bursts pinned to their hosts will show whether tiny, freshly formed galaxies are typical homes for FRBs in the early universe.
Primary source
This summary is based on ESA/Webb and the peer-reviewed paper. Read the original for full details, data and caveats.
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