Gravitational Wave Cosmology: Be Careful of the Black Hole Mass Spectrum

Understand

Gravitational waves (GWs) from compact binary coalescences (CBCs) offer insights into the universe expansion.

• The spectral siren method, used without electromagnetic counterparts (EMC), infers cosmic expansion (Hubble constant) by relating detector and source frame masses of black hole (BH) mergers.
• However, heuristic mass models (broken power law, power law plus peak, multipeak) may introduce biases in the Hubble constant estimation, potentially up to 3 sigma with 2000 detected GW mergers.
• These biases stem from the models inability to consider redshift evolution and unexpected mass features.