Repeating fast radio bursts reveal memory from minutes to an hour

TL;DR

This study analyzes repeating fast radio bursts (FRBs) from two sources, revealing that their emission patterns exhibit memory effects over minutes to an hour, suggesting correlated triggers like neutron star crustal failures.

Contribution

The paper demonstrates that repeating FRBs show long-timescale memory effects and models these behaviors within a self-organized criticality framework, providing insights into their physical origins.

Findings

Memory observed over minutes to an hour in FRB sources

Burst rate structures and Hurst exponent indicate long-term correlations

Power-law tail in waiting time distribution consistent with variable Poisson process

Abstract

Fast radio bursts (FRBs) are brief, luminous pulses with unknown physical origin. The repetition pattern of FRBs contains essential information about their physical nature and emission mechanisms. Using the two largest samples of FRB 20121102A and FRB 20201124, we report that the sources of the two FRBs reveal memory over a large range of timescales, from a few minutes to about an hour. The memory is detected from the coherent growths in burst-rate structures and the Hurst exponent. The waiting time distribution displays a power-law tail, which is consistent with a Poisson model with a time-varying rate. From cellular automaton simulations, we find that these characteristics can be well understood within the physical framework of a self-organized criticality system driven in a correlation way, such as random walk functions. These properties indicate that the triggers of bursts are correlated, preferring the crustal failure mechanism of neutron stars.