The Thousand-Pulsar-Array programme on MeerKAT XIV: On the high linearly polarized pulsar signals

TL;DR

This study applies a novel polarization sampling method to a large pulsar dataset, significantly improving RVM fitting success rates and supporting the coherent curvature radiation model for pulsar emission.

Contribution

The paper introduces a new approach using highly polarized samples to better fit the RVM across a large pulsar sample, reducing failure rates substantially.

Findings

RVM fitting success increased from 41% to 95% with the new method.

Only 5% of pulsars failed RVM fitting after applying the approach.

Results support the coherent curvature radiation as the pulsar emission mechanism.

Abstract

The S-shaped swing of the linear polarization position angle (PPA) observed in many pulsars can be interpreted by the rotating vector model (RVM). However, efforts to fit the RVM for a large sample of pulsars observed with the MeerKAT telescope as a part of the Thousand-Pulsar-Array (TPA) programme, only succeeded for about half the cases. High time-resolution studies suggest that the failed cases arise due to the presence of orthogonal polarization modes, or highly disordered distribution of PPA points. One such example is PSR~J1645-0317. Recently it has been shown that the RVM can be recovered in this pulsar by using only time samples which are greater than 80% linearly polarized. In this work we test this novel approach on the brightest 249 pulsars from the TPA sample, of which 177 yield sufficient highly polarized samples to be amenable to our method. Remarkably, only 9 of these pulsars (5%) now fail to fit the RVM as opposed to 59% from the original analysis. This result favours the paradigm that the underlying mechanism is coherent curvature radiation.