The Impact of Astrophysical Priors on Parameter Inference for GW230529

Abstract

We investigate the effects of prior selection on the inferred mass and spin parameters of the neutron star-black hole merger GW230529\_181500. Specifically, we explore models motivated by astrophysical considerations, including massive binary and pulsar evolution. We examine mass and spin distributions of neutron stars constrained by radio pulsar observations, alongside black hole spin observations from previous gravitational wave detections. We show that the inferred mass distribution highly depends upon the spin prior. Specifically, under the most restrictive, binary stellar evolution models, we obtain narrower distributions of masses with a black hole mass of $4.3_{-0.1}^{+0.1}{M}_{\odot }$and neutron star mass of $1.3_{-0.03}^{+0.03}{M}_{\odot }$ where, somewhat surprisingly, it is the prior on component spins which has the greatest impact on the inferred mass distributions. Re-weighting using neutron star mass and spin priors from observations of radio pulsars, with black hole spins from observations of gravitational waves, yields the black hole and the neutron star masses to be $3.8_{-0.6}^{+0.5}{M}_{\odot }$ and $1.4_{-0.1}^{+0.2}{M}_{\odot }$ respectively. The sequence of compact object formation -- whether the neutron star or the black hole formed first -- cannot be determined at the observed signal-to-noise ratio. However, there is no evidence that the black hole was tidally spun up.

Published in MNRAS Letters

References in corpus (10)

• Robust parameter estimation for compact binaries with ground-based gravitational-wave observations using the LALInference software library
• Observation of gravitational waves from two neutron star-black hole coalescences
• Impact of Massive Binary Star and Cosmic Evolution on Gravitational Wave Observations I: Black Hole-Neutron Star Mergers
• On the Rate of Neutron Star Binary Mergers from Globular Clusters
• Exploring the Lower Mass Gap and Unequal Mass Regime in Compact Binary Evolution
• A pulsar in a binary with a compact object in the mass gap between neutron stars and black holes
• Modelling Neutron Star-Black Hole Binaries: Future Pulsar Surveys and Gravitational Wave Detectors
• The role of supernova convection for the lower mass gap in the isolated binary formation of gravitational wave sources
• Mass Distribution and Maximum Mass of Neutron Stars: Effects of Orbital Inclination Angle
• Everything everywhere all at once: A detailed study of GW230529

Cited by in corpus (3)

• Possible binary neutron star merger history of the primary of GW230529
• Challenging a binary neutron star merger interpretation of GW230529
• Characterizing Compact-object Binaries in the Lower Mass Gap with Gravitational Waves