On the high frequency polarization of pulsar radio emission

TL;DR

This study examines pulsar polarization at 4.9 GHz, revealing significant depolarization and correlations with rotational energy, while also revisiting pulsar profile classifications and discovering pulsars with increasing circular polarization at high frequencies.

Contribution

It provides new high-frequency polarization data for 32 pulsars, analyzes polarization changes across frequencies, and identifies correlations with pulsar energy loss, offering insights into pulsar emission mechanisms.

Findings

Significant depolarization occurs at high frequencies.

Correlation between polarization degree and rotational energy loss.

Discovery of pulsars with increasing circular polarization at high frequencies.

Abstract

We have analyzed the polarization properties of pulsars at an observing frequency of 4.9 GHz. Together with low frequency data, we are able to trace polarization profiles over more than three octaves into an interesting frequency regime. At those high frequencies the polarization properties often undergo important changes such as significant depolarization. A detailed analysis allowed us to identify parameters, which regulate those changes. A significant correlation was found between the integrated degree of polarization and the loss of rotational energy E^dot. The data were also used to review the widely established pulsar profile classification scheme of core- and cone-type beams. We have discovered the existence of pulsars which show a strongly increasing degree of circular polarization towards high frequencies. Previously unpublished average polarization profiles, recorded at the 100m Effelsberg radio telescope, are presented for 32 radio pulsars at 4.9 GHz. The data were used to derive polarimetric parameters and emission heights.