An international team of astronomers detected and identified the origin of the most distant fast radio burst (fast radio burst) ever recorded. The signal, which traveled for more than ten billion years to reach Earth, allows studying the matter between galaxies and better understanding the evolution of the Universe.
The signal, designated FRB 20240304B, was detected by the MeerKAT radio telescope in South Africa, as part of the MeerTRAP project. Using observations from the James Webb Space Telescope, the researchers were able to identify the galaxy of origin and determine its distance.
When the signal was emitted, the Universe was about three billion years old, much less than its current age, estimated at 13.8 billion years. The discovery, published in the scientific journal Science, more than doubles the previous distance record for this kind of phenomenon.
Fast radio bursts are extremely brief signals, lasting only a few milliseconds, but releasing enormous amounts of energy. Their origin remains under study, though one of the most supported hypotheses points to magnetars — neutron stars with extraordinarily strong magnetic fields.
A small, intensely star-forming galaxy
The galaxy hosting the source of the signal revealed unexpected characteristics: it is relatively small, has a low abundance of elements heavier than helium, and is in a vigorous star-forming phase.
These characteristics are compatible with the hypothesis that some fast radio bursts originate in young magnetars, formed after the explosion of massive stars. This explanation contrasts with other theories that involve, for example, the merger of older neutron stars.
“The galaxy hosting this burst is surprisingly small, metal-poor, and undergoing a very active period of star formation,” explains Laura Driessen, researcher at the University of Sydney and co-author of the study.
The identification of the galaxy required the James Webb Space Telescope, since it was not visible even with the largest ground-based telescopes. The combination of radio observations with infrared imaging and spectroscopic data allowed locating the origin of the signal and studying the galaxy’s characteristics.
A signal that reveals the matter between galaxies
In addition to allowing the study of the host galaxy, the burst acts like a cosmic lighthouse. As it traversed space for billions of years, the radio waves interacted with the matter along their path, carrying information about the gas and other structures between galaxies.
This possibility is particularly relevant because a substantial part of the matter between galaxies is difficult to observe directly. The analysis of fast radio bursts could, thus, help astronomers map that matter and better understand the evolution of cosmic structures.
“We captured a fast radio burst from a time when the Universe was only about three billion years old, and we used that brief radio signal to study the matter it passed through over billions of years,” says Manisha Caleb, a researcher at the University of Sydney and one of the study’s leads.
The team now intends to search for even more distant signals, approaching the first generations of stars. The researchers believe that bursts sufficiently intense could, in principle, be detected from even earlier phases of the Universe’s history.
The discovery also underscores the potential of facilities such as MeerKAT and the future SKA Observatory, which is being built in Australia and South Africa and is expected to enable radio observations with unprecedented sensitivity.
