Accuracy of inference on the physics of binary evolution from gravitational-wave observations

Abstract

The properties of the population of merging binary black holes encode some of the uncertain physics underlying the evolution of massive stars in binaries. The binary black hole merger rate and chirp-mass distribution are being measured by ground-based gravitational-wave detectors. We consider isolated binary evolution, and explore how accurately the physical model can be constrained with such observations by applying the Fisher information matrix to the merging black hole population simulated with the rapid binary-population synthesis code COMPAS. We investigate variations in four COMPAS parameters: common-envelope efficiency, kick-velocity dispersion, and mass-loss rates during the luminous blue variable and Wolf-Rayet stellar-evolutionary phases. We find that ∼ 1000 observations would constrain these model parameters to a fractional accuracy of a few per cent. Given the empirically determined binary black hole merger rate, we can expect gravitational-wave observations alone to place strong constraints on the physics of stellar and binary evolution within a few years. Our approach can be extended to use other observational data sets; combining observations at different evolutionary stages will lead to a better understanding of stellar and binary physics.

Constraining the Fraction of Binary Black Holes Formed in Isolation and Young Star Clusters with Gravitational-wave Data

“…Furthermore, we assume a specific model for BH natal kicks, which are highly uncertain and can crucially impact the properties of merging systems (e.g. Belczynski et al 2016b;Mapelli et al 2017;Barrett et al 2018;Wysocki et al 2018;Gerosa et al 2018). Even the prescriptions for common envelope affect the properties of merging systems significantly (here we consider only one value of α = 3).…”

Double neutron star formation: merger times, systemic velocities, and travel distances

“…The semi-analytic methods here may be combined in the future with binary population synthesis simulations that can produce realistic distributions of pre-SN orbital configurations. As the number of detections increases, compact object merger events can start to be used to constrain the-oretical binary evolution models (for example, see work by Mandel et al 2017;Barrett et al 2018). In particular, a significant sample of DNS travel distances (as measured by the distance between the EM counterpart to future LIGO/Virgo merger events and the DNS host galaxies) would greatly help constrain the distribution of pre-SN orbital configurations using the results presented here.…”

stroopwafel: simulating rare outcomes from astrophysical populations, with application to gravitational-wave sources

“…The samples shown here are not weighted for the sensitivity of gravitational-wave interferometers. In addition, they correspond to a particular model chosen in our simulation, and in practice many variations of this model need to be explored for a meaningful comparison with observations (e.g., Barrett et al 2018). For example, the metallicity in this model is fixed to Z = 0.001 and we expect to form more massive black holes at lower metallicities (e.g., Spera et al 2015;Belczynski et al 2016).…”

“…In this work we adopt κ = 2 (red dotted line). models and constrain them with observations, particularly those of gravitational-wave sources Barrett et al 2018;Vigna-Gómez et al 2018). COMPAS interpolates between and extrapolates beyond stellar evo-lutionary tracks based on algorithms from the code SSE (Hurley et al 2000), which rely on analytic fits of single star evolution from Pols et al (1998).…”