To be published in the Proceedings of the International Europhysics Conference on High Energy Physics (HEP 97), 19-26 August 1997, Jerusalem, Israel PL8: Astro-Particle Physics Georg G. Raffelt (raffelt@mppmu.mpg.de) Max-Planck-Institut f¨ ur Physik (Werner-Heisenberg-Institut) F¨ ohringer Ring 6, 80805 M¨ unchen, Germany Abstract. Recent developments of those areas of astro-particle physics are dis- cussed that were represented at the HEP97 conference. In particular, the current status of direct and indirect dark-matter searches and of TeV neutrino and γ-ray astronomy will be reviewed. 1 Introduction Astro-particle physics is such a wide field that it is certainly impossible to review its current status in a single lecture. To make a sensible selection it seemed most appropriate to cover those areas which were represented in the parallel sessions of this conference, i.e. mostly experimental topics in the ar- eas of dark-matter detection and of neutrino and γ -ray astronomy. One of the most cherished dark-matter candidates is the lightest supersymmetric particle so that accelerator searches for supersymmetry are of immediate cosmological importance, yet I consider this topic to lie outside of my assignment. Like- wise the laboratory searches for neutrino masses and oscillations are of direct astrophysical and cosmological significance, yet they exceed the boundaries of my task. Finally, I will not coverthe very exciting recent developments in MeV to GeV neutrino astronomy (solar, supernova, and atmospheric neutri- nos) because they are reviewed by another speaker [1]. 2 Dark Matter Searches 2.1 Dark Stars (MACHOs) The existence of huge amounts of dark matter in the universe is now es- tablished beyond any reasonable doubt, but its physical nature remains an unresolved mystery [2, 3]. A number of well-known arguments negate the pos- sibility of a purely baryonic universe, but also point to significant amounts of nonluminous baryons. If some of them are in the galactic halo one most natu- rally expects them to be in the form of Massive Astrophysical Compact Halo Objects (MACHOs)—small and thus dim stars (brown dwarfs, M-dwarfs) or stellar remnants (white dwarfs, neutron stars, black holes). Stellar remnants and M-dwarfs are virtually excluded [4], which leaves us with brown dwarfs, i.e. normal stars with a mass below 0.08 M ⊙ (solar masses) so that they are too small to ignite hydrogen.