Significance entry distribution. The black histogram corresponds to all pixels of the map shown in Fig. 1a with non-zero entries, the grey histogram to all pixels outside of the final exclusion map. The green line represents the fit of a Gaussian distribution to the grey histogram, the best-fit mean and width are μ = −0.043 ± 0.005 and σ = 1.008 ± 0.005, respectively. A Gaussian distribution with mean μ = 0 and width σ = 1 is shown by the orange, dashed line for comparison.