Radio emission from a pulsar's magnetic pole revealed by general relativity

TL;DR

This paper uses polarimetric radio observations of PSR J1906+0746 to validate a geometrical model of pulsar polarization, reconstruct the emission map, and test general relativity effects like spin precession, with implications for neutron star populations.

Contribution

It provides the first detailed polarimetric emission map of a pulsar's magnetic pole and tests GR predictions through pulsar spin precession observations.

Findings

Validated the geometrical model of pulsar polarization.

Predicted the disappearance of detectable emission by 2028.

Constrained the relativistic treatment of pulsar polarization and measured the pulsar beaming fraction.

Abstract

Binary pulsars are affected by general relativity (GR), causing the spin axes of each pulsar to precess. We present polarimetric radio observations of PSR J1906+0746 that demonstrate the validity of the geometrical model of pulsar polarisation. We reconstruct the (sky-projected) polarisation emission map over the pulsar's magnetic pole and predict the disappearance of the detectable emission by 2028. Two additional tests of GR are performed in this system, including the spin-precession for strongly self-gravitating bodies. We constrain the relativistic treatment of the pulsar polarisation model and measure the pulsar beaming fraction, with implications for the population of neutron stars and the expected rate of neutron star mergers.