FAST pulsar database: I. Polarization profiles of 682 pulsars

TL;DR

This paper presents polarization profiles for 682 pulsars observed with FAST, including 460 new profiles, revealing diverse polarization features and deriving geometric parameters, enhancing understanding of pulsar emission mechanisms.

Contribution

It provides a large, new database of pulsar polarization profiles from FAST, including first-time observations, and analyzes polarization features and geometry parameters.

Findings

Diverse polarization features observed across pulsars.

Linear and circular polarization vary with frequency.

Pulsars with high linear polarization tend to have larger Edot.

Abstract

Pulsar polarization profiles are very basic database for understanding the emission processes in pulsar magnetosphere. After careful polarization calibration of the 19-beam L-band receiver and verification of beam-offset observation results, we obtain polarization profiles of 682 pulsars from observations by the Five-hundred-meter Aperture Spherical radio Telescope (FAST) during the survey tests for the Galactic Plan Pulsar Snapshot (GPPS) survey and other normal FAST projects. Among them, polarization profiles of about 460 pulsars are observed for the first time. The profiles exhibit diverse features. Some pulsars have a polarization position angle curve with a good S-shaped swing, and some with orthogonal modes; some have components with highly linearly components or strong circularly polarized components; some have a very wide profile, coming from an aligned rotator, and some have an interpulse from a perpendicular rotator; some wide profiles are caused by interstellar scattering. We derive geometry parameters for 190 pulsars from the S-shaped position angle curves or with orthogonal modes. We find that the linear and circular polarization or the widths of pulse profiles have various frequency dependencies. Pulsars with large fraction of linear polarization are more likely to have a large Edot.