Gamma ray signatures from Galactic neutralino annihilation

¹ Dipartimento di Fisica “Enrico Fermi”, Università di Pisa, via F. Buonarroti 2, Pisa 56127, Italy
² Dipartimento di Fisica, Università di Siena, via Roma 56, Siena 53100, Italy
³ Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, via F. Buonarroti 2, Pisa 56127, Italy e-mail: giada.valle@pi.infn.it

Received: 6 April 2004
Accepted: 26 May 2004

Abstract

Direct observations of cosmic photon spectra from neutralino annihilation at energies above EGRET data might reveal the presence of weakly interacting massive particle (WIMP) dark matter in the Universe.
Calculations of the rates for the continuum γ channel and γ-ray line are reviewed. Both the continuum γ-ray spectrum and the γ-ray line arising from neutralino annihilation are studied. Flux estimates are inherently model-dependent; they suffer from uncertainties due to the large allowed ranges in supersymmetrical parameter-space and from a variety of astrophysical models of the dark matter halo profiles. Our analysis allows detection predictions for orbital and ground-based experiments. As an application, we investigate the number of signal events expected to be detected in an orbital experiment (AMS-02) and we make a comparison with atmospheric Cerenkov telescopes.