Anisotropies of gravitational-wave standard sirens as a new cosmological probe without redshift information

Understand

Gravitational waves (GWs) from compact binary stars at cosmological distances are promising and powerful cosmological probes, referred to as the GW standard sirens.

• With future GW detectors, we will be able to precisely measure source luminosity distances out to a redshift $z\sim5$.
• To extract cosmological information, previously proposed cosmological studies using the GW standard sirens rely on source redshift information obtained through an extensive electromagnetic follow-up campaign.
• However, the redshift identification is typically time consuming and rather challenging.