Highly polarized components of integrated pulse profiles

TL;DR

This paper investigates highly polarized components in pulsar pulse profiles through observational analysis and simulations, revealing their dependence on pulsar geometry, emission modes, and propagation effects.

Contribution

It introduces a model that explains the appearance and polarization characteristics of highly polarized pulse components based on emission processes and geometry.

Findings

Highly polarized components are associated with specific emission modes.

Depolarization results from orthogonal modes or scattering.

Polarization characteristics depend on the line of sight and pulsar geometry.

Abstract

Highly polarized components of pulse profiles are investigated by analyzing observational data and simulating the emission processes. The highly polarized components appear at the leading or trailing part of a pulse profile, which preferably have a flat spectrum and a flat polarization angle curve compared with the low polarized components. By considering the emission processes and propagation effects, we simulate the distributions of wave modes and fractional linear polarization within the entire pulsar emission beam. We show that the highly polarized components can appear at the leading, central, and/or trailing parts of pulse profiles in the models, depending on pulsar geometry. The depolarization is caused by orthogonal modes or scattering. When a sight line cuts across pulsar emission beam with a small impact angle, the detected highly polarized component will be of the O mode, and have a flat polarization angle curve and/or a flat spectrum as observed. Otherwise, the highly polarized component will be of the X mode and have a steep polarization angle curve.