Invited Talk - Splinter JungeAG

Monday, 13 September 2021, 16:50   (virtual JAG)

Revisiting the Galactic Double Neutron Star merger and LIGO detection rates

Kathrin Grunthal, Michael Kramer, Gregory Desvignes
Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany; Jodrell Bank Centre for Astrophysics, University of Manchester, M13 9PL, UK; LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris, 5 Place Jules Janssen, 92195, Meudon, France

We revisit the merger rate for Galactic double neutron star (DNS) systems in light of recent observational insight into the longitudinal and latitudinal beam shape of the relativistic DNS PSR J1906+0746. Due to its young age and its relativistic orbit, the pulsar contributes significantly to the estimate of the joint Galactic merger rate. We follow previous analyses by modelling the underlying pulsar population of nine merging DNS systems and study the impact and resulting uncertainties when replacing simplifying assumptions made in the past with actual knowledge of the beam shape, its extent and the viewing geometry. We find that the individual contribution of PSR J1906+0746 increases to R=6+28−5 Myr−1 although the values is still consistent with previous estimates given the uncertainties. We also compute contributions to the merger rates from the other DNS systems by applying a generic beam shape derived from that of PSR J1906+0746, evaluating the impact of previous assumptions. We derive a joint Galactic DNS merger rate of RgenMW=32+19−9Myr−1, leading to a LIGO detection rate of RgenLIGO=3.5+2.1−1.0Myr−1 (90% conf. limit), considering the upcoming O3 sensitivity of LIGO. As these values are in good agreement with previous estimates, we conclude that the method of estimating the DNS merger and LIGO detection rates via the study of the radio pulsar DNS population is less prone to systematic uncertainties than previously thought.