Raggi gamma per effetto Compton inverso da materia oscura galattica

Up to now, direct searches for dark matter did not give positive results. Another promising detection strategy seems to be the indirect one, which consists in looking for signals of the presence of dark matter in terms of its final annihilation products: e+ , e− , μ+ , μ− , τ + , τ − , W + , W − , p, d, γ, ν, ... Recent results from a number of indirect detection experiments have pointed to an excess of electrons and positrons in the galactic halo, compared with the expected smooth astrophysical background. Such an anomaly could have a dark matter origin. When the exceeding highly relativistic e± propagate from their sources through the galaxy, they lose energy by interacting with the interstellar medium, the whole process being modellized by a specific diffusion-loss equation. We have studied in detail the interaction - via inverse Compton scattering (ICS) - between the e± produced by the DM annihilation processes and the low-energy photons which constitute the inter-stellar radiation field. When a relativistic e± scatters off a low-energy photon, it transfers part of its kinetic energy to the target, which becomes highly energetic. The first goal of our work is to compute the differential flux of these high-energy photons generated by the ICS processes, reproducing the results published by M.Cirelli and P.Panci in their article, Inverse Compton constraints on the Dark Matter e± excesses. After having fixed the galactic geometry by choosing the observational regions of interest and the dark matter density profiles, we perform the whole calculation in the Thomson limit, using both analytic and numerical methods. This procedure will be repeated by scanning a wide range of dark matter masses and for several annihilation channels. The natural prosecution of this thesis would be to constrain the computed ICS signal by comparing it with the recent data published by the Fermi-LAT Collaboration (April 2009), in order to pose upper limits on the dark datter annihilation cross section.