A Generalized Algorithmic Framework for Detecting Faraday Rotation Measure Flares in Repeating Fast Radio Bursts

TL;DR

This paper introduces a robust algorithmic framework for detecting Faraday rotation measure flares in repeating fast radio bursts, enabling a uniform analysis of environmental variability across the FRB population.

Contribution

The authors develop a generalized, statistically robust pipeline for automated detection and characterization of RM flares in FRBs, facilitating a systematic census of environmental changes.

Findings

High-confidence RM flares are rare among the studied FRBs.

FRB 20220529A shows a significant RM flare, unlike other repeaters.

Most repeaters exhibit intrinsic fluctuations or secular evolution rather than discrete flares.

Abstract

Variations in the Faraday rotation measure (RM) of repeating fast radio bursts (FRBs) provide critical diagnostics of the dynamically evolving magneto-ionic environments surrounding their progenitors. Sudden, transient ``RM flares'' can trace the passage of discrete magneto-ionic structures, such as stellar coronal mass ejections from the companion or other dense plasma clumps, across the line of sight. However, identifying these rare events is difficult because RM evolution manifests a wide range of complex behaviors, from smooth, long-term trends to chaotic stochasticity, further complicated by highly non-uniform temporal sampling. This complexity makes it a non-trivial challenge to distinguish localized physical flares from intrinsic environmental volatility. We present a generalized algorithmic framework that establishes a statistically robust methodology for the automated detection and characterization of RM flares. By objectively isolating discrete transient perturbations from quiescent backgrounds, this pipeline enables the first uniform census of environmental variability across the FRB population. Applying this framework to 15 repeating FRBs, we find that high-confidence RM flares are remarkably rare, with FRB 20220529A being the only source to exhibit a statistically significant event under standardized parameters. Other active repeaters instead display high-level intrinsic fluctuations or secular evolution. This work provides a rigorous foundation for distinguishing between different modes of local plasma dynamics, offering a crucial diagnostic tool for identifying the diverse progenitor systems and local environments of FRBs.