Precision cosmology from future lensed gravitational wave and electromagnetic signals

Kai Liao,Xi-Long Fan,Zong-Hong Zhu,Xuheng Ding,Marek Biesiada

doi:10.1038/s41467-017-01152-9

Abstract

The standard siren approach of gravitational wave cosmology appeals to the direct luminosity distance estimation through the waveform signals from inspiralling double compact binaries, especially those with electromagnetic counterparts providing redshifts. It is limited by the calibration uncertainties in strain amplitude and relies on the fine details of the waveform. The Einstein telescope is expected to produce 104–105 gravitational wave detections per year, 50–100 of which will be lensed. Here, we report a waveform-independent strategy to achieve precise cosmography by combining the accurately measured time delays from strongly lensed gravitational wave signals with the images and redshifts observed in the electromagnetic domain. We demonstrate that just 10 such systems can provide a Hubble constant uncertainty of 0.68% for a flat lambda cold dark matter universe in the era of third-generation ground-based detectors.

Highlights

The standard siren approach of gravitational wave cosmology appeals to the direct luminosity distance estimation through the waveform signals from inspiralling double compact binaries, especially those with electromagnetic counterparts providing redshifts
For the lensed gravitational wave (GW) and EM systems, we show that both time-delay and Fermat potential difference measurements will be considerably improved compared to the traditional approach to lensed quasars in EM domain[3]
The time delays measured through GW signals are supposed to be very accurate due to transient nature of double compact object (DCO) merger events (~0.1 s) observed by ground-based GW detectors

Summary

Introduction

The standard siren approach of gravitational wave cosmology appeals to the direct luminosity distance estimation through the waveform signals from inspiralling double compact binaries, especially those with electromagnetic counterparts providing redshifts. It is limited by the calibration uncertainties in strain amplitude and relies on the fine details of the waveform. Knowing the NS equation of state, a tidal correction to the GW phase in the late-inspiral signal of NS–NS systems[14] or spectral features of the post merger phase[15] can be used to break the mass-redshift degeneracy allowing an estimation of the source redshift and luminosity distance from the GW signal alone Another approach is to infer redshifts statistically, by comparing measured (redshifted) mass distribution of NS with a universal rest frame NS mass distribution[10, 16]

Methods

Results

Conclusion