Galactic merger rate of double-neutron-star systems and prospects for detecting gravitational waves

We present the most up-to-date estimates of the Galactic merger rate of double-neutron-star (DNS) systems and inferred detection rates with LIGO (Laser Interferometer Gravitational-Wave Observatory). We calculate a probability density function (PDF) of rate estimates, P(R), taking into account three known systems (PSRs B1913+16, B1534+12, and J0737-3039). The most likely values of the DNS merger rate lie in the range 3 - 190 Myr(-1) depending on different pulsar models. For our reference model, we find that the most probable event rates are about I per 30 years and I per 2 days, for initial and advanced LIGO, respectively. Comparing the peak rate estimates, we find that the discovery of J0737-3039 increases the estimated DNS merger rate by a factor similar to 6 compared to what has been previously known. In addition to studying individual pulsar models, we calculate a global PDF of rate estimates, motivated by a strong correlation between the peak rate estimates and a pulsar luminosity function. Comparing the global PDF with observed supernova lb/c rate, we show how the supernova rates can set stringent constraints on the DNS merger rate. Finally, we discuss the implications of new discoveries such as of PSR J1756-2251. the 4-th DNS in the Galactic disk, and PSR J1906+0746, a DNS candidate.