Impact of gravitational waveform model systematics on the measurement of the Hubble constant

TL;DR

This paper investigates how uncertainties in gravitational waveform models affect the measurement of the Hubble constant using binary neutron star observations, finding biases are currently below statistical uncertainties.

Contribution

It quantifies the systematic biases introduced by different waveform models on Hubble constant measurements with current gravitational-wave detectors.

Findings

Systematic biases are below statistical uncertainties for current detectors.

Four waveform models were compared to assess model-dependent biases.

The study uses a synthetic population of 38 binary neutron star sources.

Abstract

Matching gravitational-wave observations of binary neutron stars with theoretical model predictions reveals important information about the sources, such as the masses and the distance to the stars. The latter can be used to determine the Hubble constant, the rate at which the Universe expands. One general problem of all astrophysical measurements is that theoretical models only approximate the real underlying physics, which can lead to systematic uncertainties introducing biases. However, the extent of this bias for the distance measurement due to uncertainties of gravitational waveform models is unknown. In this study, we analyze a synthetic population of 38 binary neutron star sources measured with Advanced LIGO and Advanced Virgo at design sensitivity. We employ a set of four different waveform models and estimate model-dependent systematic biases on the extraction of the Hubble constant using the bright siren method. Our results indicate that systematic biases are below statistical uncertainties for the current generation of gravitational-wave detectors.