Friday, May 16, 2008
TeV-Gamma-Astronomy with the H.E.S.S. Telescopes in Namibia – Cosmic Gamma Rays from Exploding Stars and Black Holes
Prof. Thomas Lohse
Physics Department, Humboldt University
H.E.S.S. (High Energy Stereoscopic System), a system of four imaging Cherenkov-Telescopes located in the Khomas-Highland of Namibia, is presently the most powerful instrument for gamma ray astronomy at energies above 100 GeV. It has fundamentally changed our picture of the gamma ray sky, bringing us closer to understanding the sources of cosmic rays and their production and acceleration mechanisms. It could be demonstrated that high energy particles are produced in the vicinity of violent astrophysical objects like supernova explosions, pulsars or black holes. A surprise was the discovery of new source populations, amongst them mysterious dark accelerators. A point-like source close to the super-massive black hole in the very centre of our galaxy gives rise to speculations about annihilating dark matter. Gamma rays from large molecular clouds around the central galactic plane show that the cosmic radiation in the galactic centre is much different from our local one. Hard gamma ray emission from very distant active galactic nuclei reveals that the range of the Universe that is transparent for gamma rays is much larger than previously expected.
Refreshments at 4:00 PM. Seminar begins at 4:10 PM.
Building 8, Room 241
For further information, please call (909) 869-4014