Top: (left) excess map of events observed in the direction of PKS 2155−304 using the H.E.S.S. II mono analysis (2013–2014 data). The inset represents the point spread function of the instrument obtained from simulations. The source position is indicated by a black dot. Right: significance distribution that corresponds to the excess map (black histogram). The distribution obtained by excluding a circular region of 0.3° radius around the source is shown in red; the results of a Gaussian fit to this distribution are also shown. Bottom: distribution of θ² (squared angular distance to PKS 2155−304) for gamma-like events obtained with the H.E.S.S. II mono analysis (filled histogram) in comparison with the normalised θ² distribution for off-source regions (black points). The vertical dashed line shows the limit of the on-source region. The energy threshold for this analysis is ≈80 GeV.