Pulsar Timing and the Discovery of a 2-Solar-Mass Neutron Star
Dr. Jason Hessels (ASTRON - Netherlands Institute for Radio Astronomy)

Pulsars are rapidly rotating, highly magnetized neutron stars that emit light-house-like pulsations of light as they rotate. "Pulsar timing" is a powerful technique, which uses the precise, clock-like nature of pulsar signals in order to infer fundamental properties of the system, such as the neutron star spin rate and slow-down behaviour. For binary pulsars, i.e. those orbiting another stellar object, it is possible to use pulsar timing techniques to precisely determine the orbital properties of the system. In some cases, this includes the inference of so-called, "post-Keplerian" or relativistic orbital parameters such as the advance of periastron. Such observations have provided the most stringent tests of General Relativity in the Strong Field regime. Here I present the discovery of the most massive neutron star yet measured, whose mass was derived via measurement of the relativistic Shapiro delay of the pulsar signal. This measurement places strong new constraints on the structure of pulsars and on the nature of super-dense, neutron-rich matter.