Heidelberg Joint Astronomical Colloquium

Speaker Stefan Schael
Title The search for dark matter with AMS on the ISS

The AMS-2 experiment will be launched with the Space Shuttle Discovery and installed on the International Space Station in 2010. It is designed to perform precision spectroscopy of many different cosmic-ray species including electrons and positrons. While the nature of dark matter is as yet unknown, dark matter annihilating in the Galactic halo is a well motivated source of cosmic-ray electrons and positrons. The cosmic-ray positron fraction data available so far show significant deviations between different measurements and from the expectation for purely secondary production. The differences between the measurements up to particle energies of 6 GeV can be understood in a framework of a charge-sign dependent solar modulation and the spectra show excellent agreement if corrected for these time-dependent effects. Recent observations of an excess in the high-energy electron spectrum by ATIC might be connected to the excess in the positron fraction. A possible source of both signatures could be dark matter annihilation or a nearby pulsar. A measurement of the anisotropy of high energy electrons could distinguish between both scenarios. Therefore the sky coverage of AMS-2 will be discussed in addition to possible dark matter scenarios and the sensitivity of the AMS-2 experiment to these effects.