Halo dark matter detection through gravitational lensing

Abstract

One of the most important problems in modern astrophysics, with possible deep implications for particle physics, is the knowledge of the nature of the nonluminous matter of galactic halos. The existence of the dark halos can be inferred from the observed rotation curves of galaxies. If the dark matter present in the halo is mainly of baryonic nature, then, except for the possibility of forming super-massive black holes, it must be mostly in form of brown dwarfs, or Jupiter-like objects in the mass range 10-6<M/M(.)<10-1. Paczynski (1986) has shown how to detect these Jupiter-like objects through gravitational micro-lensing. The author discusses the main features of the micro-lensing events.