The H.E.S.S. telescopes have surveyed the Milky Way for the past 15 years searching for sources of gamma radiation. The H.E.S.S. collaboration includes scientists of the Institute of Astronomy and Astrophysics of the University of Tübingen led by Professor Andrea Santangelo and Dr. Gerd Pühlhofer. They are interested in sources of very high energy gamma radiation in the TeV energy range, i.e. in the range of 1012 electron volts, corresponding to a trillion of the energy of visible light photons. For the first time they have been able to classify celestial objects using only the emission of this kind of radiation: very likely they are supernova remnants, which are celestial objects that emerge after the explosion of massive stars. The results are published in a special edition of the scientific journal Astronomy & Astrophysics, which appears on the occasion of the 15th anniversary of the H.E.S.S. telescopes with the largest set of science results of the project to date.