Parameters of the power-law (equation (13)) fits shown in Fig. 5. The two fit parameters are not independent, so the uncertainty on the normalization in the range covered by the data is much smaller than the quoted uncertainty on A (this is especially apparent in model b400l9). Since the typical mass is of order |$10^{15} \, \mathrm{M}_\odot$|⁠, we expect the uncertainty on log₁₀A to be about 15 × that on α, which is roughly the case.