Long-term project observations for project P455 semester 2025OCTS_01

This project is to continue timing and profile studies of the first double-pulsar system, a unique laboratory for gravitational physics. Important results published in our 53-page Phys. Rev. X paper (2021) include the first measurements of higher-order light-propagation effects and of the relativistic deformation of the orbit and highlight the importance of a long term observational campaign, including VLBI observations, for this remarkable system. The main aims of this proposal are to provide the strongest tests to date for general relativity and to measure for the first time the moment-of-inertia of a neutron star. Additionally, we will determine the system geometry, map the pulsar beams via geodetic precession, and search for the reappearance of Pulsar B. We exploit the high sensitivity and broad bandwidth of the UWL receiver. We are collaborating with the MeerKAT Double Pulsar Timing team to optimise combination of MeerKAT and UWL data.