Temporal Variations in Pulsar Spectro-Polarimetry: Findings from millisecond pulsar J2144-5237 using Parkes UWL receiver

TL;DR

This study introduces a novel package for analyzing time-varying spectro-polarimetric data of pulsars, demonstrating its application on MSP J2144-5237 to reveal orbital phase-dependent polarization variations and rotation measure changes.

Contribution

It is the first to investigate and characterize the temporal variations in the spectro-polarimetric properties of pulsars, providing new insights into pulsar emission and magnetospheric processes.

Findings

RM varies with orbital phase

Stokes I, Q, V spectra are correlated over orbit

Stokes U shows correlation and anticorrelation with I

Abstract

While the temporal variations of the spectro-polarimetric nature of pulsars remains unexplored, this investigation offers significant potential for uncovering key insights into pulsar emission mechanisms, magnetic field geometry, and propagation effects within the magnetosphere. We developed a package for investigating time-varying spectral behavior for full Stokes parameters and demonstrate it on a millisecond pulsar (MSP) J2144-5237 in a binary system (orbital period ~10 days) using the Parkes UWL receiver. In this study we report rotation measure (RM) variation with orbital phase. We find that the temporal variations in the spectra of Stokes I, Q, and V are generally correlated throughout the orbit, while Stokes U exhibits intervals of both correlation and anticorrelation with Stokes I, depending on the orbital phase. We also provide a Poincare sphere representation of the polarization properties of J2144-5237, demonstrating a systematic temporal change of Poincare sphere location for the main component with orbital phase. To our knowledge, this is the first investigation of time-varying properties of the spectro-polarimetric nature of any pulsars or MSPs. Extending this study to probe the spectro-temporal nature of full Stokes data on a larger sample of MSPs or pulsars has the potential to provide vital information on emission mechanisms inside the magnetosphere, interstellar propagation effects, and binary interactions.