Multi-Messenger Constraint on the Hubble Constant $H_0$ with Tidal Disruption Events

Abstract

Tidal disruption events (TDEs), apart from producing luminous electromagnetic (EM) flares, can generate potentially detectable gravitational wave (GW) burst signals by future space-borne GW detectors. In this Letter, we propose a methodology to constrain the Hubble constant $H_0$ by incorporating the TDE parameters measured by EM observations (e.g., stellar mass, black hole (BH) mass and spin, and other orbital parameters) into the observed TDE GW waveforms. We argue that an accurate knowledge of the BH spin could help constrain the orbital inclination angle, hence alleviating the well-known distance-inclination degeneracy in GW waveform fitting. For individual TDEs, the precise redshift measurement of the host galaxies along with the luminosity distance $D_{\rm L}$ constrained by EM and GW signals would give a self-contained measurement of $H_0$ via Hubble's law, completely independent of any specific cosmological models.