Observations of the shell-type supernova remnant SN1006 have been carried out with the HESS system of Cherenkov telescopes during 2003 (18.2 h with two operating telescopes) and 2004 (6.3 h with all four telescopes). No evidence for TeV $\gamma$-ray emission from any compact or extended region associated with the remnant is seen and resulting upper limits at the 99.9% confidence level are up to a factor 10 lower than previously-published fluxes from CANGAROO. For SN1006 at its current epoch of evolution we define limits for a number of important global parameters. Upper limits on the $\gamma$-ray luminosity (for E = 0.26 to 10 TeV, distance d = 2 kpc) of $L_\gamma < 1.7$ $\times$ 1033 erg s-1, and the total energy in corresponding accelerated protons, $W_{\rm p}<1.6$ $\times$ 1050 erg are estimated (for proton energies $E_{\rm p} \sim 1.5$ to 60 TeV and assuming the lowest value n=0.05 cm-3 of the ambient target density discussed in literature). Extending this estimate to cover the range of proton energies observed in the cosmic ray spectrum up to the knee (we take here $E_{\rm p} \sim$ 1 GeV to 3 PeV, assuming a differential particle index -2) gives $W_{\rm p}<6.3$ $\times$ 1050 erg. A lower limit on the post-shock magnetic field of $B>25~\mu$G results when considering the synchrotron/inverse-Compton framework for the observed X-ray flux and $\gamma$-ray upper limits.

We report the detection of TeV $\gamma$-rays from the shell-type supernova remnant RX J0852.0-4622 with data of 3.2 h of live time recorded with H.E.S.S. in February 2004. An excess of (700 $\pm$ 60) events from the whole remnant with a significance of 12 $\sigma$ was found. The observed emission region is clearly extended with a radius of the order of 1 degree and the spatial distribution of the signal correlates with X-ray observations. The spectrum in the energy range between 500 GeV and 15 TeV is well described by a power law with a photon index of $\Gamma=2.1 \pm 0.1_{stat} \pm 0.2_{syst}$ and a differential flux at 1 TeV of $\varphi$ 1TEV= (2.1 $\pm 0.2_{stat} \pm 0.6_{syst}) \times 10^{-11} cm^{-2} s^{-1} TeV^{-1}$. The integral flux above 1 TeV was measured to be $\Phi$ (E > 1 TeV) = (1.9 $\pm 0.3_{stat} \pm 0.6_{syst}) \times 10^{-11} cm^{-2} s^{-1}$, which is at the level of the flux of the Crab nebula at these energies. More data are needed to draw firm conclusions on the magnetic field in the remnant and the type of the particle population creating the TeV $\gamma$-rays.

X-ray binaries are composed of a normal star in orbit around a neutron star or stellar-mass black hole. Radio and X-ray observations have led to the presumption that some X-ray binaries called microquasars behave as scaled down active galactic nuclei. Microquasars have resolved radio emission that is thought to arise from a relativistic outflow akin to active galactic nuclei jets, in which particles can be accelerated to large energies. Very high energy gamma-rays produced by the interactions of these particles have been observed from several active galactic nuclei. Using the High Energy Stereoscopic System, we find evidence for gamma-ray emission >100 GeV from a candidate microquasar, LS 5039, showing that particles are also accelerated to very high energies in these systems.

The serendipitous discovery of an unidentified extended TeV $\gamma$-ray source close to the galactic plane named HESS J1303-631 at a significance of 21 standard deviations is reported. The observations were performed between February and June 2004 with the H.E.S.S. stereoscopic system of Cherenkov telescopes in Namibia. HESS J1303-631 was discovered roughly 0.6 \degres north of the binary system PSR B1259-63/SS 2883, the target object of the initial observation campaign which was also detected at TeV energies in the same field of view. HESS J1303-631 is extended with a width of an assumed intrinsic Gaussian emission profile of $\sigma$ = (0.16 $\pm$ 0.02)\degres and the integral flux above 380 GeV is compatible with constant emission over the entire observational period of (17$\pm$ 3)% of the Crab Nebula flux. The measured energy spectrum can be described by a power-law dN/dE $\sim$ E$^{-\Gamma}$ with a photon index of $\Gamma$ = 2.44 $\pm 0.05$_{stat} \pm$ 0.2$_{syst}$. Up to now, no counterpart at other wavelengths is identified. Various possible TeV production scenarios are discussed.

The detection of non-baryonic dark matter through its gamma-ray annihilation in the centre of our galaxy has been studied. The gamma fluxes according to different models have been simulated and compared to those expected to be observed with the Alpha Magnetic Spectrometer (AMS), during a long-term mission on board of the International Space Station. Under the assumption that the dark matter halo is composed of the lightest, stable supersymmetric particle, the neutralino, the results of the simulations in the framework of mSUGRA models, show that with a cuspy dark matter halo or a clumpy halo, the annihilation gamma-ray signal would be detected by AMS. More optimistic perspectives are obtained with the Anomaly Mediated Supersymmetry Breaking (AMSB) model. The latter leads also to a cosmologically important 6Li abundance. Finally, the discovery potential for the massive Kaluza-Klein dark matter candidates has been evaluated and their detection looks feasible.

The H.E.S.S experiment (for High Energy Stereoscopic System) consists of four imaging Cherenkov telescopes situated in the Namibia Khomas Highland desert (1800 m asl). Its main characteristics are the low energy threshold (100 GeV) and substantial flux sensitivity (1% Crab units). The combination of the four telescope data analysis provide good background rejection and angular resolution. Recent results on the performance and operation are reported here.

A significant fraction of the energy density of the interstellar medium is in the form of high-energy charged particles (cosmic rays). The origin of these particles remains uncertain. Although it is generally accepted that the only sources capable of supplying the energy required to accelerate the bulk of Galactic cosmic rays are supernova explosions, and even though the mechanism of particle acceleration in expanding supernova remnant (SNR) shocks is thought to be well understood theoretically, unequivocal evidence for the production of high-energy particles in supernova shells has proven remarkably hard to find. Here we report on observations of the SNR RX J1713.7 - 3946 (G347.3 - 0.5), which was discovered by ROSAT in the X-ray spectrum and later claimed as a source of high-energy bold gamma-rays of TeV energies (1 TeV = 1012 eV). We present a TeV bold gamma-ray image of the SNR: the spatially resolved remnant has a shell morphology similar to that seen in X-rays, which demonstrates that very-high-energy particles are accelerated there. The energy spectrum indicates efficient acceleration of charged particles to energies beyond 100 TeV, consistent with current ideas of particle acceleration in young SNR shocks.