Example phenomenological distribution described in Section 2.1. Top: one-dimensional mass distribution parameterized according to Equation (5): a broken power law with slopes α₁ and α₂ and break at γ_high, with a notch filter between γ_low and γ_high with amplitude A. Bottom: corresponding two-dimensional distribution, constructed from the one-dimensional distribution with a mass ratio–dependent pairing function following Equation (6). The color bar denotes the probability density p(m₁, m₂).