A new test of general relativity - Gravitational radiation and the binary pulsar PSR 1913+16

Pulse arrival times of a binary pulsar were observed for seven years using average pulse profiles representing about five minutes of data acquisition with synchronous averaging and a least squares procedure for fitting the standard profiles. A model was formulated using relativistic terms, both secular and periodically varying with orbital phase, and it was assumed that the pulsar is an accurate clock. Tests were made to determine the magnitude of possible systematic biases. The component masses and absolute size of the orbit were determined. These values were used, together with the well-determined orbital period and eccentricity, to calculate the rate at which the orbital period should decay as energy is lost from the system via gravitational radiation. The results agreed strikingly with general relativity but disagreed with most other theories of gravitation. For this reason, the companion star must be a neutron star or black hole.