Relativistic Spin Precession in the Double Pulsar

The double pulsar PSR J0737–3039A/B consists of two neutron stars in a highly relativistic orbit that displays a roughly 30-second eclipse when pulsar A passes behind pulsar B. Describing this eclipse of pulsar A as due to absorption occurring in the magnetosphere of pulsar B, we successfully used a simple geometric model to characterize the observed changing eclipse morphology and to measure the relativistic precession of pulsar B's spin axis around the total orbital angular momentum. This provides a test of general relativity and alternative theories of gravity in the strong-field regime. Our measured relativistic spin precession rate of [fleqn,10pt,legalpaper]{article} {amssymb} {amsfonts} {amsmath} {empty} {document} \(4.77{^∘}_{-0{^∘}.65}^{+0{^∘}.66}\) {document} per year (68% confidence level) is consistent with that predicted by general relativity within an uncertainty of 13%.