Scientists have uncovered further evidence linking fast radio bursts (FRBs)—brief, intense flashes of energy brighter than entire galaxies—to magnetars, which are highly magnetic neutron stars. These magnetars would need to produce powerful winds of charged particles, capable of creating bubbles of super-heated ionized gas, or plasma, around them.
FRBs, which last only milliseconds, can emit as much energy in a fraction of a second as the Sun does in three days. Despite their intensity, the origins of these bursts have been elusive since the first FRB was discovered in 2001 using data from the Parkes Observatory in Australia. The challenge lies in the fact that most FRBs flash once and disappear, making it difficult for scientists to trace their source. The few FRBs that repeat have led researchers to question whether both repeating and non-repeating FRBs share the same origin.
To delve deeper into this mystery, a team of astronomers used the Very Large Telescope (VLT) in Chile to study FRB 20201124A, an active radio burst originating from a source about 1.3 billion light-years away. This FRB has experienced multiple episodes of explosive activity, making it an ideal candidate for investigation. The team, led by Gabriele Bruni from the National Institute for Astrophysics, detected the faintest radio continuum emission associated with an FRB to date. This discovery supports their “nebular model,” which suggests that the radio emission is produced by a plasma bubble surrounding the central engine responsible for the FRBs, inflated by winds of charged particles from the magnetar.
Bruni explained that this finding helps confirm the connection between FRBs and remnants of massive stars, with magnetars being the leading candidates. These neutron stars, born from the remnants of stars at least eight times the mass of the Sun, collapse into incredibly dense objects with powerful magnetic fields when their nuclear fuel is exhausted.
Magnetars have been suspected as the source of repeating FRBs, but the exact mechanism remains unclear. Possible explanations include starquakes within the neutron star or glitches in its rotation. The new research indicates that the “magnetoionic medium”—the combination of plasma and magnetic fields surrounding the FRB source—plays a crucial role in the emission of these bursts.
While this study strengthens the link between FRBs and magnetars, it doesn’t yet clarify whether repeating and non-repeating FRBs share the same origins. Bruni and his team are continuing their research, aiming to detect more plasma bubbles around other FRBs to refine their nebula model and better understand the physical properties of these enigmatic bursts.
