Probing Correlations in the Binary Black Hole Population with Flexible Models

Understand

The astrophysical formation channels of binary black hole systems predict correlations between their mass, spin, and redshift distributions, which can be probed with gravitational-wave observations.

• Population-level analysis of the latest LIGO-Virgo-KAGRA catalog of binary black hole mergers has identified evidence for such correlations assuming linear evolution of the mean and width of the effective spin distribution as a function of the binary mass ratio and merger redshift.
• However, the complex astrophysical processes at play in compact binary formation do not necessarily predict linear relationships between the distributions of these parameters.
• In this work, we relax the assumption of linearity and instead search for correlations using a more flexible cubic spline model.