Constraining the dense matter equationofstate with radio pulsars
Abstract
Radio pulsars provide some of the most important constraints for our understanding of matter at supranuclear densities. So far, these constraints are mostly given by precision mass measurements of neutron stars (NS). By combining single measurements of the two most massive pulsars, J0348+0432 and J0740+6620, the resulting lower limit of 1.98 M_{☉} (99 per cent confidence) of the maximum NS mass, excludes a large number of equations of state (EOSs). Further EOS constraints, complementary to other methods, are likely to come from the measurement of the moment of inertia (MOI) of binary pulsars in relativistic orbits. The Double Pulsar, PSR J07373039A/B, is the most promising system for the first measurement of the MOI via pulsar timing. Reviewing this method, based in particular on the first MeerKAT observations of the Double Pulsar, we provide wellfounded projections into the future by simulating timing observations with MeerKAT and the SKA. For the first time, we account for the spindown massloss in the analysis. Our results suggest that an MOI measurement with 11 per cent accuracy (68 per cent confidence) is possible by 2030. If by 2030 the EOS is sufficiently well known, however, we find that the Double Pulsar will allow for a 7 per cent test of LenseThirring precession, or alternatively provide a ∼3σmeasurement of the nexttoleading order gravitational wave damping in GR. Finally, we demonstrate that potential new discoveries of double NS systems with orbital periods shorter than that of the Double Pulsar promise significant improvements in these measurements and the constraints on NS matter.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 July 2020
 DOI:
 10.1093/mnras/staa2107
 arXiv:
 arXiv:2007.07725
 Bibcode:
 2020MNRAS.497.3118H
 Keywords:

 dense matter;
 equation of state;
 gravitation;
 pulsars: general;
 pulsars: individual: J07373039A;
 Astrophysics  Solar and Stellar Astrophysics;
 Astrophysics  High Energy Astrophysical Phenomena;
 General Relativity and Quantum Cosmology
 EPrint:
 13 pages, 8 figures. Accepted by MNRAS