The Extreme Faraday Effect in Fast Radio Bursts
Year: 2025
Type: article
Abstract: Fast radio bursts (FRBs) are a type of highly polarized, millisecond-duration electromagnetic pulse in the radio band, which is mostly produced at cosmological distances. These properties provide a natural laboratory for testing the extreme Faraday effect, a phenomenon in which two different propagation modes of a pulse separate after passing through a dense, highly ionized, and magnetized medium. We derive the critical condition (e.g., rotation measure) for the extreme Faraday effect to occur in FRBs, which exceeds the currently observed maximum value but remains within the theoretically predicted range. Some new features of FRBs (in particular, radio bursts with much shorter durations) after undergoing the extreme Faraday effect are predicted, such as sudden sign reversals of circular polarization, conspicuous frequency drifting, and emergency of extremely high circular polarization degrees. A potential application of this effect in FRBs is that, by comparing morphological differences of the two separated twin modes, one can identify the variations of plasma properties over extremely short timescales along the propagation path. Therefore, if this effect is found with future observations, it would provide a new tool for probing dense, magnetized environments near FRB sources.
Authors: Yu-Chen Huang, Zi-Gao Dai
Institution: University of Science and Technology of China
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,400
Award: G2023442668
OpenAlex ID: W4409249602