Hubble parameter estimation via dark sirens with the LISA-Taiji network

Area of Science:

• Cosmology
• Astrophysics
• Gravitational Wave Astronomy

Background:

• The Hubble parameter quantifies the universe's expansion rate.
• A significant tension exists between early-universe and late-universe measurements of the Hubble parameter.
• Independent, high-precision measurements are crucial to resolve this cosmological tension.

Purpose of the Study:

• To assess the capability of the future LISA-Taiji gravitational wave observatory network in measuring the Hubble parameter.
• To determine the precision achievable for Hubble parameter measurements using gravitational waves from compact binary coalescence events.

Main Methods:

• Utilizing the standard siren approach with gravitational wave signals from compact binary mergers.
• Simulating gravitational wave data from the proposed LISA-Taiji network operating in the millihertz band.
• Incorporating statistical and instrumental noise models relevant to space-borne gravitational wave detectors.

Main Results:

• The LISA-Taiji network can constrain the Hubble parameter to within 0.3% accuracy over a five-year observation period.
• Potential for achieving even higher precision, with scatters potentially reduced to 0.1% or better.
• Demonstrates the power of gravitational wave astronomy as an independent cosmological probe.

Conclusions:

• The LISA-Taiji network promises to deliver highly accurate measurements of the Hubble parameter.
• Gravitational wave standard sirens offer a powerful, independent method to probe cosmic expansion.
• This capability will be instrumental in resolving the current Hubble tension in cosmology.