Humboldt-Universität zu Berlin - Mathematisch-Naturwissen­schaft­liche Fakultät - Experimentelle Elementarteilchenphysik

High Energy Stereoscopic System (H.E.S.S.)

 H.E.S.S. telescopes


H.E.S.S. is an array of five Imaging Atmospheric Cherenkov Telescopes located in the southern hemisphere in the Khomas Highland of Namibia. It is operated by a collaboration of about 220 scientists and allows the detection of gamma-rays with energies between 50 GeV and 100 TeV. In its Phase I (since 2004) the system has been fully operational with four identical 12m-diameter telescopes whose high sensitivity allowed the discovery of numerous galactic and extragalactic sources. In the summer of 2012, an additional fifth telescope with a mirror diameter of 28m has been added (H.E.S.S. Phase II). This telescope is located in the center of the existing array and is the largest Cherenkov telescope ever built. Its larger mirror surface helps to improve the sensitivity even more and lowers the energy threshold.

The Berlin H.E.S.S. group combines data analysis activities (supernovae as possible sources of cosmic rays, binaries and pulsarwind nebulae, search for pulsed emission from pulsars, dark matter and exotic physics) with responsibility for the data acquisition system of the experiment.

Research Topics

  • Pulsed Gamma-ray Emission

    Pulsars are highly magnetized and rapidly rotating neutron stars which emit a beam of high energetic gamma radiation. Due to the rotating beam of light a regular pulsed signal with periods ranging from 1.4 ms to 8.5 s is observed on earth (lighthouse effect). The actual mechanisms of radiation emission is still poorly known and subject of ongoing investigation.

  • TeV Gamma-ray Binaries

    Of particular interest are binary systems such as PSR 1259-63, a highly eccentric binary system of a pulsar and a high mass Be companion star. From those systems the pulsar wind interaction with its surroundings as well as the jets physics can be studied.

  • Dark Matter Annihilation

    The annihilation of dark matter (DM) particles is assumed to result in secondary particles (photons, neutrinos, positrons) whose energy spectrum ends at the mass of the DM particle and might show characteristic features (e.g. annihilitation lines). Detection of such secondary particles facilitates so called indirect DM searches. Such searches with H.E.S.S. have targeted dwarf galaxies (dim galaxis orbiting the Milky Way) and regions close to the Galactic Center both of which are believed to harbour increased concentrations of DM.

  • Pulsar Wind Nebulae

    Pulsar wind nebulae (PWNe) are luminous structures visible around pulsars. They are powered by the spin-down energy loss of the pulsar and have been detected at various energies (e.g. X-ray, high-energy). PWNe form the largest known population of Galactic gamma-ray sources and it is assumed that many currently unidentified sources will be classified as PWNe. Observations with H.E.S.S. in combination with multiwavelength data help to understand the evolution and structure of PWN.

  • Supernova Remnants

    Supernova remnants (SNR) result from the explosions of stars in supernovae. Apart from heating up the interstellar medium they accelerate cosmic rays which is of particular interest since the acceleration mechanisms of extremly high energetic particles are still poorly known.