- Joined Aug 27, 2009
Scientists using the H.E.S.S. observatory in Namibia have detected the highest energy gamma rays ever from a dead star called a pulsar. The energy of these gamma rays clocked in at 20 tera-electronvolts, or about 10 trillion times the energy of visible light. This observation is hard to reconcile with the theory of the production of such pulsed gamma rays, as the international team reports in the journal Nature Astronomy.
Pulsars are the left-over corpses of stars that spectacularly exploded in a supernova. The explosions leave behind a tiny, dead star with a diameter of just some 20 kilometers, rotating extremely fast and endowed with an enormous magnetic field.
"These dead stars are almost entirely made up of neutrons and are incredibly dense: a teaspoon of their material has a mass of more than five billion tons, or about 900 times the mass of the Great Pyramid of Giza," explains H.E.S.S. scientist Emma de Oña Wilhelmi, a co-author of the publication working at DESY.