Eccentricity distributions of merging BH binaries formed in star clusters for the three choices of r_h,0, at the moment their GW frequency becomes larger than 10 and 0.01 Hz. Bottom panels give the eccentricity distributions for ejected binaries (lowest eccentricities), in-cluster inspirals, and GW captures (largest eccentricities) separately. Note that at 0.01 Hz, GW captures all have e ≃ 1 because they all form at frequencies |$f\gt 0.1\,$|Hz. In this calculation, we have adopted the constant momentum natal kick model of Section 2.2, and we have only included late time mergers, occurring at t > 8 Gyr.