Schematic of the Milky Way and its spiral arms, along with firmly identified PWNe, candidates, and energetic pulsars (Ė > 10³⁵ erg s-1) without detected TeV wind nebula. The yellow and blue curves outline the sensitivity horizon of the HGPS for point-like sources with an integrated gamma-ray luminosity (1–10 TeV) of 1% and 10% of the Crab luminosity, respectively (see H.E.S.S. Collaboration 2018, for details).