No Evidence for Second-Scale Periodicity in FRB 20201124A from FAST Observations

TL;DR

This study used FAST telescope data to search for second-scale periodicity in FRB 20201124A but found no significant evidence, challenging previous claims of such periodicity and informing models of FRB progenitors.

Contribution

The paper introduces a robust procedure for detecting second-scale periodicity in FRBs and applies it to FAST data, providing a null result that questions earlier periodicity claims.

Findings

No significant second-scale periodicity detected in FRB 20201124A

Results challenge previous claims of ~1.7s periodicity

Method provides a robust framework for future periodicity searches

Abstract

Fast Radio Bursts (FRBs) are bright and short radio flashes of cosmological origin. Although a great number of FRBs were detected in the last two decades, their progenitors and the physical processes that create them are unknown. In recent years, magnetars have been proposed as one of the leading progenitor candidates. A striking feature that can hint at such a magnetar origin is second-scale periodicity. In this paper, we define a robust procedure to search for such periodicity and estimate the significance of its results. We search for such periodicity in the bursts of FRB 20201124A, observed by the Five-hundred-meter Aperture Spherical Telescope (FAST) between April and June 2021. Our analysis does not find any significant periodicity. We discuss the differences between our non-detection and the ~1.7s periodicity claim by C. Du et al. (2025).