The corner plot of the best-fitting parameters of Eq. 6, for fitting log($\overline{{\sigma }_{\text{b}}}$) as a function of the rescaled true input log(NIV′), across all simulations spanning count rates from 0.001 cts/s to 30 cts/s, and number of bins from 50 to 1000. The values of the best fit parameters shown here differ from those displayed in Table 1, as the fit was performed for log($\overline{{\sigma }_{\text{b}}}$) as a function of the rescaled $\log \left({\text{NIV}}^{\prime }\right)=\log (\text{NIV})-\overline{\log (\text{NIV})}$. Table 1 instead shows the parameter values for the fit of log($\overline{{\sigma }_{\text{b}}}$) as a function of log(NIV), and those are the ones that should be used for estimating NEV_b from $\overline{{\sigma }_{\text{b}}}$.