RRAT J2325-0530: A Rotating Radio Transient with an Atypical Waiting-time Distribution

TL;DR

This study analyzes the emission patterns of RRAT J2325-0530 using FAST observations, revealing clustered bursts, a Weibull waiting-time distribution, and complex polarization, indicating intricate magnetospheric processes behind its sporadic radio emission.

Contribution

It introduces a detailed analysis of the waiting-time distribution and polarization behavior of RRAT J2325-0530, highlighting the role of quasi-random emission with rotational modulation and complex magnetospheric dynamics.

Findings

Waiting-time distribution follows a Weibull model with shape parameter $k  1$.

Detected clustering of pulses in groups of 2 to 5.

Complex polarization behavior suggests non-standard magnetospheric activity.

Abstract

We present 1.25 GHz observations of the rotating radio transient (RRAT) J2325-0530, conducted with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Approximately 60% of detected single pulses occur in clusters of 2 to 5 consecutive bursts. Consequently, the waiting-time distribution between successive single pulses exhibits a pronounced excess at one rotation period, deviating from the exponential distribution expected for a Poisson process. After grouping consecutive bursts into single emission events, the recalculated waiting-time distribution is well described by a Weibull distribution with a shape parameter $k \gtrsim 1$. Monte Carlo simulations incorporating both intrinsic burst on-windows and rotational modulation successfully reproduce the observed one-rotation excess. These results suggest that RRAT J2325-0530 emits through a quasi-random process with on-windows slightly longer than its spin period, modulated by the the rotation of emission beam. Additionally, the polarization position angle shows complex behavior that cannot be fully described by the standard rotating vector model, and several pulses exhibit quasi-periodic micro-structures. Taken together, these features indicate complex magnetospheric dynamics underlying the sporadic emission behavior of RRAT J2325-0530.