SA astronomers win top EU prize


14 March 2007

Six scientists from South Africa’s North West University are part of an international team that scooped the European Union’s prestigious Descartes prize for their groundbreaking research on the Earth’s galaxy via gamma rays.

Among the recipients of the €1-million Descartes prize for research, announced in Belgium last week, were Professors Okkie De Jager and Christo Raubenheimer, Christo Venter, computer specialist Matthew Holleran, Namibian astronomer Isak Davids and German post-doctoral astronomer Ingo Buesching.

The six North West University scientists are part of a European Union-funded team of about 100 who run the High-Energy Stereoscopic System (Hess), four telescopes in Namibia that were specially developed for the study of gamma rays.

The South African government invested over R30-million in the construction of the telescopes, and has contributed millions more to establishing the Hess site – at Goellschau in the Khomas Highland of Namibia – and funding SA’s participation in the project.

According to the SA Press Association (Sapa), the Hess team – which shared the €1-million prize with two other projects – plans to put its €330 000 to good use by constructing Hess 2, a 30-metre telescope that will be joined with the existing four.

“It will be the world’s largest reflector for astronomical purposes,” De Jager told Sapa.

Revolutionising astrophysics
Hess detects high-energy gamma rays that originate from the remnants of dead stars, then pinpoints the source of those rays from within the Milky Way, the galaxy that contains the Earth. “We opened a new window on the universe, one that was not open before,” De Jager told Sapa.

The European Union (EU) said in a statement that Hess had revolutionised existing astronomical observation techniques and increased human knowledge and understanding of the Milky Way and beyond.

“With EU support they have designed and built the system, developed the complex software needed to collect and analyse data, and offered training to young astronomers and astrophysicists,” the EU said.

The Hess telescopes detect light emitted when cosmic gamma rays are absorbed in the Earth’s atmosphere. By reconstructing the trajectory of these rays, an image of the “very-high-energy gamma-ray sky” is generated.

In just three years since it began operating, Hess has “revolutionised the field of astrophysics with a number of major achievements,” the EU said.

These included “the first resolved image of a supernova shock wave acting as a cosmic particle accelerator, the first survey of the central region of our galaxy revealing a large number of novel gamma-ray sources, a detailed study of high-energy radiation from the centre of our galaxy, and the discovery of a stellar black hole – or ‘microquasar’ – generating gamma rays.

“The Hess results reveal entirely new views of a ‘nonthermal’ universe, governed by processes acting at energies well beyond the energy scales provided by even the hottest stars in the cosmos.” reporter

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