Astronomers using NASA's James Webb Space Telescope have pinpointed the host galaxy of the most distant fast radio burst (FRB) observed to date, according to a study published Thursday in the journal Science and reported by NASA on Oct. 8, 2026. The burst, designated FRB 20240304B, was detected by the MeerTRAP team using the MeerKAT telescope on March 4, 2024.

Webb's NIRCam instrument detected a small dwarf galaxy actively forming stars at the burst's location, and its NIRSpec instrument measured a redshift of 2.148, corresponding to a time about 3 billion years after the big bang. The galaxy was 1,000 times less massive than the team expected, and its star-formation rate suggests most of its stars may have formed within just 30 million years. Lead author Manisha Caleb of the University of Sydney said the result makes a neutron-star merger origin very unlikely, since such mergers are expected to take billions of years; a young magnetar would fit the youthful host.

The burst's signal also carried imprints of two cosmic structures along its path: a previously unknown galaxy cluster at a redshift of 0.3, about 3.5 billion light-years from Earth, and the nearby Virgo Cluster, about 54 million light-years away. The team estimates MeerKAT may detect and localize several FRBs per year at a redshift greater than 1.0, with Webb remaining essential for studying their host galaxies.