Population synthesis of double neutron stars

TL;DR

This paper models the population of double neutron stars in the Galaxy using detailed binary evolution simulations, accounting for spin, magnetic fields, natal kicks, and detection biases, to predict observable properties in radio and gravitational wave data.

Contribution

It introduces a comprehensive population synthesis approach that integrates spin evolution, magnetic decay, and Galactic dynamics to better understand double neutron star populations.

Findings

Predicted distributions of double neutron star properties in radio and gravitational wave observations.

Estimated the number of double neutron stars detectable by LIGO and VIRGO.

Analyzed the impact of evolutionary parameters on the observable populations.

Abstract

Using the StarTrack binary population synthesis code we model the population of double neutron stars in the Galaxy. We include a detailed treatment of the spin evolution of each pulsar due to processes such as spin-down and spin-up during accretion events as well as magnetic field decay. We also model the spatial distribution of double neutron stars by including their natal kicks and subsequent propagation in the Galactic gravitational potential. This synthetic pulsar population is compared to the observed sample of double neutron stars taking into account the selection effects of detection in the radio band, to determine the most likely evolutionary parameters. With these parameters we determine the properties of the double neutron star binaries detectable in gravitational waves by the high frequency interferometers LIGO and VIRGO. In particular, we discuss the distributions of chirp masses and mass ratios in samples selected by their radio or gravitational wave emission.