Detecting Pulsar Polarization below 100 MHz with the Long Wavelength Array

TL;DR

This study uses the Long Wavelength Array to measure pulsar polarization and Faraday rotation at frequencies below 100 MHz, revealing new insights into pulsar emission and the interstellar medium.

Contribution

First low-frequency polarization measurements of pulsars using LWA1, providing new data on rotation measures and polarization profiles below 100 MHz.

Findings

Measured RMs for 15 pulsars at 25-88 MHz

Revealed polarization characteristics and emission heights at low frequencies

Derived Galactic magnetic field values along pulsar lines of sight

Abstract

Using the first station of the Long Wavelength Array (LWA1), we examine polarized pulsar emission between 25 and 88 MHz. Polarized light from pulsars undergoes Faraday rotation as it passes through the magnetized interstellar medium. Observations from low frequency telescopes are ideal for obtaining precise rotation measures (RMs) because the effect of Faraday rotation is proportional to the square of the observing wavelength. With these RMs, we obtained polarized pulse profiles to see how polarization changes in the 25-88 MHz range. The RMs were also used to derive values for the electron density weighted average Galactic magnetic field along the line of sight. We present rotation measures and polarization profiles of 15 pulsars acquired using data from LWA1. These results provide new insight into low-frequency polarization characteristics and pulsar emission heights, and complement measurements at higher frequencies.