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… (More)
Very high energy gamma-rays probe the long-standing mystery of the origin of cosmic rays. Produced in the interactions of accelerated particles in astrophysical objects, they can be used to image cosmic particle accelerators. A first sensitive survey of the inner part of the Milky Way with the High Energy Stereoscopic System (HESS) reveals a population of… (More)
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… (More)
The serendipitous discovery of an unidentified extended TeV γ-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 •… (More)
Observations of the shell-type supernova remnant SN1006 have been carried out with the H.E.S.S. system of Cherenkov telescopes during 2003 (18.2h with two operating telescopes) and 2004 (6.3h with all four telescopes). No evidence for TeV γ-ray emission from any compact or extended region associated with the remnant is seen and resulting upper limits at the… (More)
We describe two patients with cerebrovascular complications of Ehlers-Danlos syndrome type IV. A 16-year-old girl with spontaneous internal carotid artery dissection and a 46-year-old woman with aneurysmal subarachnoid hemorrhage and multiple aortic dissections were both deficient in collagen type III, analyzed in cultured skin fibroblasts. To our… (More)
In image coding, the choice of a good image coding algorithm is very dependent on the image content. Based on this fact, dynamic coding algorithms have been designed. They try to nd an optimal coding scheme for each image segment. They rely on an exhaustive search of the best coding algorithm. Evaluation of all algorithms is computationally very intensive… (More)
The BL Lac object Mkn 501 went into a very high state of activity during 1997, both in VHE γ-rays and X-rays. We present here results from observations at energies above 250 GeV carried out between March and October 1997 with the CATČerenkov imaging Telescope.