Implications of PSR J0737-3039B for the Galactic NS-NS Binary Merger Rate

摘要

The Double Pulsar (PSR J0737-3039) is the only neutron star-neutron star(NS-NS) binary in which both NSs have been detectable as radio pulsars. TheDouble Pulsar has been assumed to dominate the Galactic NS-NS binary mergerrate R_g among all known systems, solely based on the properties of thefirst-born, recycled pulsar (PSR J0737-3039A, or A) with an assumption for thebeaming correction factor of 6. In this work, we carefully correctobservational biases for the second-born, non-recycled pulsar (PSR J0737-0737B,or B) and estimate the contribution from the Double Pulsar on R_g usingconstraints available from both A and B. Observational constraints from the Bpulsar favour a small beaming correction factor for A (~2), which is consistentwith a bipolar model. Considering known NS-NS binaries with the bestobservational constraints, including both A and B, we obtain R_g=21_{-14}^{+28}per Myr at 95 per cent confidence from our reference model. We expect thedetection rate of gravitational waves from NS-NS inspirals for the advancedground-based gravitational-wave detectors is to be 8^{+10}_{-5} per yr at 95per cent confidence. Within several years, gravitational-wave detectionsrelevant to NS-NS inspirals will provide us useful information to improvepulsar population models.