FRB Reaches Cosmic Noon

A fast radio burst at redshift 2.148 traced to a distant host galaxy with JWST and MeerKAT, illustrating how FRBs map the universe’s ionised gas.

Fast Radio Burst Traces Galaxy Formation at Cosmic Noon

Detecting FRB 20240304B on March 4, 2024, the MeerKAT telescope in South Africa captured a burst that originates from a redshift of 2.148, implying the signal began its journey over 11 billion years ago. It carried a dispersion measure of about 2330 parsecs per cubic centimeter, a fingerprint of the ionised gas it travelled through. JWST with its NIRCam and NIRSpec instruments later pinpointed the host galaxy as a low mass, clumpy star forming system, a finding that supports magnetars as a likely engine for fast radio bursts.

This discovery doubles the redshift reach of localised FRBs and shows FRBs can trace ionised baryons across roughly 80 percent of the universe's history. The sightline passes near the Virgo Cluster and a foreground group, revealing complex magnetic field structures on gigaparsec scales. The event underscores FRBs as tools to study galaxy formation during the era of peak star formation, commonly called cosmic noon, and demonstrates how modern telescopes work together to map the unseen.

This milestone shows how FRBs can become precise cosmological probes when combined with deep multi-wavelength data. It underscores the need for global collaboration across radio, optical, and space based facilities. Yet it also raises questions about biases in the growing FRB sample and the risk that only the brightest, easiest to localize events guide theory.

If more such events are found, we may map the distribution of ionised gas and magnetic fields across most of cosmic history. The challenge is building a representative sample and calibrating dispersion measures to the evolving universe. The story points to a future where FRBs enrich our understanding of both stellar birth and the large scale structure of the cosmos.

Highlights

More discoveries like this could reshape how we map the unseen regions of the cosmos.