Abdalla, H.Barnard, M.Böttcher, M.Davids, I.D.Garrigoux, T.Ivascenko, A.Krüger, P.P.Pekeur, N.W.Seyffert, A.S.Spanier, F.Sushch, I.Van der Walt, D.J.Van Rensburg, C.Venter, C.Wadiasingh, Z.H.E.S.S. Collaboration2018-05-092018-05-092018Abdalla, H. et al. 2018. The supernova remnant W49B as seen with H.E.S.S. and Fermi-LAT. Astronomy and astrophysics, 612: Article no A5. [https://doi.org/10.1051/0004-6361/201527843]0004-63611432-0746 (Online)http://hdl.handle.net/10394/26836https://doi.org/10.1051/0004-6361/201527843https://www.aanda.org/articles/aa/pdf/2018/04/aa27843-15.pdfThe supernova remnant (SNR) W49B originated from a core-collapse supernova that occurred between one and four thousand years ago, and subsequently evolved into a mixed-morphology remnant, which is interacting with molecular clouds (MC). Gamma-ray observations of SNR-MC associations are a powerful tool to constrain the origin of Galactic cosmic rays, as they can probe the acceleration of hadrons through their interaction with the surrounding medium and subsequent emission of non-thermal photons. We report the detection of a γ-ray source coincident with W49B at very high energies (VHE; E > 100 GeV) with the H.E.S.S. Cherenkov telescopes together with a study of the source with five years of Fermi-LAT high-energy γ-ray (0.06–300 GeV) data. The smoothly connected, combined source spectrum, measured from 60 MeV to multi-TeV energies, shows two significant spectral breaks at 304 ± 20 MeV and 8.4−2.5+2.2 GeV; the latter is constrained by the joint fit from the two instruments. The detected spectral features are similar to those observed in several other SNR-MC associations and are found to be indicative of γ-ray emission produced through neutral-pion decayenGamma rays: generalISM: supernova remnantsISM: cloudsArticle