Astronomers used the James Webb Space Telescope to identify and measure the host galaxy of FRB 20240304B, the most distant fast radio burst seen to date. The burst itself was detected by South Africa’s MeerKAT radio telescope on March 4, 2024. NASA says Webb’s NIRCam found a galaxy at the burst’s location, while NIRSpec measured its redshift at 2.148, placing the event about 3 billion years after the Big Bang.
Fast radio bursts are millisecond-long flashes of radio emission whose physical origins remain uncertain. The host of FRB 20240304B is an actively star-forming dwarf galaxy that the research team said was about 1,000 times less massive than expected.
What the young host suggests
The galaxy’s star-formation rate suggests most of its stars may have formed within about 30 million years. That makes a slow merger between two neutron stars less likely for this burst, according to the team, and fits more closely with theories involving a young, highly magnetic neutron star known as a magnetar. The study does not establish that magnetars cause all fast radio bursts.
The signal also preserved evidence of matter it crossed on its way to Earth. Researchers identified the imprint of a previously unknown galaxy cluster and the nearby Virgo Cluster, illustrating how distant fast radio bursts can be used to trace otherwise unseen structures between galaxies.
