Very high energy gamma rays from the composite SNR G 0.9+0.1

Very high energy (>100 GeV) gamma-ray emission has been detected for the first time from the composite supernova remnant G 0.9+0.1 using the HESS instrument. The source is detected with a significance of ≈13σ, and a photon flux above 200 GeV of (5.7±0.7_stat±1.2_sys)×10^-12 cm^-2 s^-1, making it one of the weakest sources ever detected at TeV energies. The photon spectrum is compatible with a power law (dN/dE ∝ E^-Γ) with photon index Γ = 2.40±0.11_stat±0.20_sys. The gamma-ray emission appears to originate in the plerionic core of the remnant, rather than the shell, and can be plausibly explained as inverse Compton scattering of relativistic electrons.