1σ confidence regions of (h, ṁ_Edd) for each source. Blue and red regions indicate the confidence regions for α^* = 0 and 1, respectively. Similarly, lighter blue and red shaded areas show the 1σ confidence regions as determined by K21b when fitting the time-lags, for α^* = 0 and 1, respectively. In the case of Mrk 142 (lower right panel), the lighter shaded areas indicate the 1σ (h, ṁ_Edd) confidence regions obtained from our best fit to the time-lags assuming M_BH = 4 × 10⁶ M_⊙ (see Sect. 6.6).