Image source: Original paper
Fast radio bursts are the most intense outbursts in the radio band of the universe.
It can release the sun’s energy for a day, a month or even a year within a time scale of milliseconds.
The mechanism and origin of the corresponding radiation are unknown.
As one of the fundamental properties of electromagnetic waves, polarization carries key information about the intrinsic radiation characteristics of the light source and the environment in which the light propagates.
General light sources are non-polarized sources, while line polarization has been detected in almost all repeated bursts of fast radio bursts.
However, circular polarization is relatively rare, and only one case of repeated burst FRB20201124A has circular polarization characteristics before.
The team of Gene Li, chief scientist of the National Astronomical Observatory of the Chinese Academy of Sciences (CAS) FAST, has found that the active repeating fast radio bursts FRB 20121102A and 20190520B have circular polarization characteristics.
The discovery boosted the number of circularly polarized repeat bursts from one to three, and the related results were published as a cover article in Science Bulletin.
Such high circular polarization limits the possibility of circular polarization from multipath propagation, the researchers said.
The mechanism for generating circular polarization may have Faraday transitions in extreme magnetic environments or the intrinsic characteristics of the FRB source.