Bolometric luminosity–spin plane for the six megamasers considered in this work. In each panel the red line and area give the expected L_bol based on Eq. (4), while the value we adopted or measured is shown by the dashed black line (and its 1σ uncertainty in yellow). We also plot the bolometric luminosity as measured from the [OIII] line (Kuo et al. 2020) as dotted blue lines. In two cases (NGC 4258, UGC 3789) there is no formal solution between the expected and measured luminosities, while for NGC 6323 the two luminosities differ by more than an order of magnitude.