Relativistic spin-precession in binary pulsars

TL;DR

Relativistic spin precession in binary pulsars has been observed and used to test general relativity, constrain spin-orbit coupling, and study pulsar emission beams and stellar core collapse.

Contribution

This paper reviews the detection of relativistic spin precession in binary pulsars and its applications in testing gravity theories and understanding pulsar emission and stellar collapse.

Findings

Consistent with GR predictions

First constraints on spin-orbit coupling for self-gravitating bodies

Beam tomography of pulsar emission beams

Abstract

After the first prediction to expect geodetic precession in binary pulsars in 1974, made immediately after the discovery of a pulsar with a companion, the effects of relativistic spin precession have now been detected in all binary systems where the magnitude of the precession rate is expected to be sufficiently high. Moreover, the first quantitative test leads to the only available constraints for spin-orbit coupling of a strongly self-gravitating body for general relativity (GR) and alternative theories of gravity. The current results are consistent with the predictions of GR, proving the effacement principle of spinning bodies. Beyond tests of theories of gravity, relativistic spin precession has also become a useful tool to perform beam tomography of the pulsar emission beam, allowing to infer the unknown beam structure, and to probe the physics of the core collapse of massive stars.