Recent Talks

The window of very high energy (VHE) gamma-ray astronomy was only opened 20 years ago by the first observation of TeV gamma-rays from the CRAB nebula. Since then the field is rapidly expanding and we are approaching the first 100 VHE sources. In contrast to the many orders of magnitude larger flux of charged VHE Cosmic Rays, gamma-rays can be extrapolated back to their sources, the high energy particle processes mostly in stellar environments and thus allows us to retrieve basic information about the ultra-relativistic universe. In my talk I will shortly describe the gamma-ray production mechanisms related to these ultra relativistic processes, losses during the transport of gamma-rays through the universe and the detection methods. This is followed by a review of classes of gamma ray emitters and the relation to multi-wavelength respectively multi-messenger observations. Because of the very rich findings of the past years some restriction to highlight observations have to be made. The talk concludes with an outlook for the next years including possible prospects to build the so-called North-CTA (Cherenkov Telescope Array) on the Canary Islands.

History: astroparticle physics emerged from particle physics and connects it to astrophysics. Early particle physics was based on cosmic ray studies. The 1930s and 1940s were dominated by the discovery of new particles (positron, muon, pion) and the problems of their identification. In the 1950s, the era of the big accelerators began. Recent astroparticle physics started in the 1980s, with solar neutrino measurements and the investigation of cosmic rays by means of particle detectors.

The last decade has brought the discovery of a large number of massive (M > 10000 M?) young open clusters in the Milky Way, which had previously not been thought to exist. I will present a brief review of these discoveries, with strong emphasis on the use of these clusters as astrophysical laboratories. I will also present the very recent discovery of a number of massive clusters concentrated towards a small region of the Scutum Arm, providing evidence for the existence of starburst activity on a much larger scale than previously assumed.

New results on the antiproton-to-proton and positron-to-all electron ratios over a wide energy range (1 – 100 GeV) have been obtained by the PAMELA mission. These data are mainly interpreted in terms of dark matter annihilation or pulsar contribution. The instrument PAMELA, in orbit since June 15th, 2006 on board the Russian satellite Resurs DK1, is daily delivering to ground 16 Gigabytes of data. The apparatus is designed to study charged particles in the cosmic radiation, with a particular focus on antiparticles for searching antimatter and signals of dark matter annihilation. A combination of a magnetic spectrometer and different detectors allows antiparticles to be reliably identified from a large background of other charged particles. The talk will illustrate the most important scientific results obtained by PAMELA, together with some of the more recent theoretical interpretations.