Polarimetry of the eclipsing pulsar PSR J1748$-$2446A

TL;DR

This study presents multi-frequency polarimetric observations of the eclipsing pulsar PSR J1748-2446A, revealing frequency-dependent eclipsing behavior and depolarization linked to stellar wind turbulence.

Contribution

First 3 GHz observations of PSR J1748-2446A, demonstrating non-eclipsing behavior at high frequency and analyzing polarization changes across orbital phases.

Findings

Pulsar signal not eclipsed at 3 GHz

Eclipses observed at lower frequencies

Depolarization correlates with orbital phase

Abstract

Observations with the Parkes radio telescope of the eclipsing millisecond binary pulsar PSR J1748$-$2446A, which is in the globular cluster Terzan 5, are presented. These include the first observations of this pulsar in the 3\,GHz frequency band, along with simultaneous observations in the 700\,MHz band and new observations around 1400\,MHz. We show that the pulsar signal is not eclipsed in the 3\,GHz band and observe the known eclipses in the lower frequency bands. We find that the observed pulse signal becomes depolarized during particular orbital phases and postulate that this depolarization occurs because of rotation-measure fluctuations resulting from turbulence in the stellar wind responsible for the eclipses.