Fast radio bursts are very brief – lasting just a few milliseconds – and very intense radio emissions, the physical origin of which remains a mystery.
Thanks to the highly precise localisation of FRB 20240304B obtained using the MeerKAT radio telescope, astronomers were able to pinpoint the host galaxy from which this signal originated.
Observations carried out with the James Webb Space Telescope revealed a small dwarf galaxy in the midst of star formation, with a precisely determined redshift of 2.148, which corresponds to a lookback time of more than 10.7 billion years. Its stellar mass is about a thousand times smaller than that generally observed for FRB host galaxies.
This discovery thus adds a further piece to the puzzle of understanding the origin of these phenomena. The characteristics of this host galaxy – which is low-mass, very young and rich in star-formation – lend support to the hypothesis of a mechanism linked to strongly magnetised neutron stars, known as magnetars, rather than that of the merger of two neutron stars, a process thought to occur after several billion years.
FRBs : tracers of matter in the Universe
Beyond the discovery itself, the FRB signal acts as a probe of the matter present between its host galaxy and Earth. In particular, its journey through the Universe has revealed the signatures of two cosmic structures : a previously unknown group of galaxies and the nearby Virgo Cluster.
FRBs could therefore become valuable tools for mapping the diffuse, invisible matter that makes up the ‘cosmic web’.
Contribution from the Paris Observatory-PSL
Parts of the data analysis for this study were carried out at the Nançay Data Centre (CDN : https://www.obs-nancay.fr/cdn/), a facility hosted by the Nançay Radio Astronomy Observatory in partnership with the Paris Observatory, the University of Orléans, OSUC and the CNRS.