An article published in the journal “Nature” reports the results of a study on some fast radio bursts linked to persistent emissions that associates that long duration with a bubble of plasma that generates that radiation. A team of researchers led by the Italian National Institute for Astrophysics registered and studied the fast radio burst with the weakest persistent emission detected so far, cataloged as FRB20201124A, and two other similar events with the VLA radio telescope collecting data that provide evidence of the presence of the plasma bubble at the origin of the radio emissions.
Fast radio bursts are characterized by the emission of enormous amounts of energy in a matter of milliseconds. In a small number of cases, a fast radio burst was recorded that coincided with a persistent emission, also in the form of radio waves. That added a new mystery to a phenomenon discovered relatively recently and is still being studied. One of these events in particular provided information that confirms a theory on the origin of the persistent emission.
The authors of this new study studied three events, in particular, the fast radio burst cataloged as FRB20201124A using the Very Large Array (VLA) radio telescope in the USA. This fast radio burst was discovered in 2020 and was produced by a source about 1.3 billion light-years away from Earth. It’s the fast radio burst with the weakest persistent radio emission detected so far.
The extraordinary sensitivity of the VLA radio telescope allowed the researchers to confirm the so-called nebular emission model. In this theory, a bubble of ionized gas surrounding the central engine of the fast radio burst generates the persistent radio emission. The detections indicate that the persistent emission comes from the same location as the fast radio burst for three events that include FRB20201124A.
The information gathered from this study also allows to investigate in depth the possible events that generate fast radio bursts. Evidence was already collected in recent years that at least some of them are associated with magnetars, neutron stars with a very powerful magnetic field. This possibility is confirmed by this study since a young magnetar can be surrounded by a bubble of ionized gas. The study also suggests X-ray binary systems in which a black hole or neutron star strips large amounts of gas from a companion and in that case, the plasma is precisely the gas that gets ionized in the interaction between the two companions.
Fast radio bursts tend to have very distant sources, in other galaxies, which makes their analysis difficult. The improvement in the quality of the detections obtained with the VLA radio telescope offers progress in solving the mystery of these extremely energetic events.
