Mass residuals as a function of Eddington rate. (a) Mass residuals (Eq. (16)), i.e. the difference between the measured reverberation virial products and those predicted by Eq. (12). The residuals are plotted vs the Eddington ratio. The solid line represents the best fit, the short-dashed lines the ±1σ envelope, and the long-dashed line the ±2.6σ envelope. Blue circles are from Table A.1, and green triangles are from Table B.1. (b) Mass residuals, i.e. the difference between the measured reverberation virial products and those predicted by Eq. (15). Panels (c) and (d) show residuals after subtraction of the best-fit relations shown in panels (a) and (b).