Distribution of S/Ns (top left panel) and relative errors for detector-frame primary masses (top right panel), detector-frame secondary masses (bottom left panel), and luminosity distances (bottom right panel). The blue, green, and orange histograms correspond to optimistic, fiducial, and pessimistic models for Pop. III BBHs, respectively, and the red histograms refer to BBHs from Pop. I-II stars (see Sects. 2.1 and 2.3 for details). In the top left panel, the dash-dotted black line marks the adopted S/N limit, and the dashed black lines in the other panels represent the adopted threshold for relative errors, where Δx are 1σ errors and x = {m_1, d,  m_2, d, d_L}.