High Energy Stereoscopic System

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High Energy Stereoscopic System or H.E.S.S. is a next-generation system of Imaging Atmospheric Cherenkov Telescopes (IACT) for the investigation of cosmic gamma rays in the 100 GeV and TeV energy range. The acronym is chosen in honor of Victor Hess, who was the first to observe cosmic rays.

The name also emphasizes two main features of the proposed installation, namely the simultaneous observation of air showers with several telescopes, under different viewing angles, and the combination of telescopes to a large system to increase the effective detection area for gamma rays. H.E.S.S. permits exploring gamma-ray sources with intensities at a level of a few thousandth parts of the flux of the Crab Nebula.

H.E.S.S. is located in Namibia, near the Gamsberg, an area well known for its excellent optical quality. The first of the four telescopes of Phase I of the H.E.S.S. project went into operation in Summer 2002; all four were operational in December 2003.

In 2004 H.E.S.S. was the first IACT experiment to spatially resolve a source of cosmic gamma rays.

In 2005, it was announced that H.E.S.S. had detected eight new high-energy gamma ray sources, doubling the known number of such sources. Two of these sources could not be identified with known objects such as supernova remnants or pulsars, raising the possibility of new physics and the existence of some new "dark" objects.

[edit] External links

• High Energy Stereoscopic System Project (H.E.S.S.) on the internet
• Nature: High energy particle acceleration in the shell of a supernova remnant
• Science: A new population of very high energy gamma-ray sources in the Milky Way
• New Scientist: Number of very high-energy gamma ray sources doubles