Low-redshift constraints on the Hubble constant from the baryon acoustic oscillation ''standard rulers'' and the gravitational wave ''standard sirens''

The multi-messenger observations of GW170817 indicated a new independent measurement of the Hubble constant (H₀). We obtain the low-redshift cosmological constraints on H₀ by combining this gravitational wave measurement with the observations of distance scales in baryon acoustic oscillations. Using Fisher information matrix, we estimate the projected constraints on H₀ from Einstein Telescope. Simulating 10³ gravitational-wave standard sirens from binary neutron star coalescences, we find that Einstein Telescope alone can constrain H₀ almost as tightly as Planck final data release in the cosmological constant plus cold dark matter model. This constraint can be further improved by combining Einstein Telescope with Dark Energy Spectroscopic Instrument. The Hubble constant tension can thus be checked by observing the standard sirens with Einstein Telescope in the future. (orig.)