HESS Gamma-Ray Telescope

One eye has opened in the High Energy Stereoscopic System (HESS) on the Khomas Highland, 100 km southwest of Namibia’s capital of Windhoek. In September, the first of four 12-meter gamma-ray telescopes that make up the European–African array began searching the skies for Cerenkov showers initiated by gamma rays hitting the atmosphere. The full array is slated to be up and running by late next year. The HESS team hopes to eventually increase the sensitivity by either quadrupling the array or adding a few larger telescopes.

The thrust of HESS and a handful of similar telescopes under construction around the world is to learn what powers violent celestial phenomena such as supernova remnants, pulsars, and active galactic nuclei (see Physics Today, June 2000, page 50 ). “Equally important,” says Riaan Steenkamp of the University of Namibia, “we want to find evidence for cosmic-ray acceleration in our own galaxy. We have a theory that works beautifully, but precious little experimental evidence.”

As part of its bid to attract astrophysics students, the university has set up exchange programs with HESS partner institutions in South Africa, France, and Germany.