Left : excess map of the Crab Nebula region within a region of 1.5° × 1.5°. The best-fit position of the excess is marked with a “+” symbol, and the expected position of the Crab Nebula, as measured in H.E.S.S. Collaboration (2020), is indicated by the green “x”. The distribution was convolved with a disk kernel of 0.05°. Center: significance map across the 7.5° × 7.5° field of view centered on Crab Nebula position. The map convolved with a disk kernel with a radius of 0.11°. 0.3° region around the Crab Nebula is masked. Right: one-dimensional distribution of the significance values, including all bins (red) and OFF-region bins (gray). The OFF-region significance distribution is fitted by a Gaussian function (dashed black line).