Outflow momentum “boost” with respect to the AGN radiative momentum output, i.e. , as a function of the outflow velocity, following Fig. 5 of Faucher-Giguère & Quataert (2012). Symbols and colour-coding as in Fig. 8. The uncertainties on the momentum boost are dominated by the errors on the outflow momentum rates. The upper limits on the outflow detection are excluded from this plot, as well as the “pure” starbursts.