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X-ray and gamma-ray observations can help understand the origin of theelectron and positron signals reported by ATIC, PAMELA, PPB-BETS, and Fermi. Itremains unclear whether the observed high-energy electrons and positrons areproduced by relic particles, or by some astrophysical sources. To distinguishbetween the two possibilities, one can compare the electron population in thelocal neighborhood with that in the dwarf spheroidal galaxies, which are notexpected to host as many pulsars and other astrophysical sources. This can beaccomplished using X-ray and gamma-ray observations of dwarf spheroidalgalaxies. Assuming the signal detected by Fermi and ATIC comes from dark matterand using the inferred dark matter profile of the Draco dwarf spheroidal galaxyas an example, we calculate the photon spectrum produced by electrons viainverse Compton scattering. Since little is known about the magnetic fields indwarf spheroidal galaxies, we consider the propagation of charged particleswith and without diffusion. Extending the analysis of Fermi collaboration forDraco, we find that for a halo mass ~ 1 billion Solar masses, even in theabsence of diffusion, the gamma-ray signal would be above the upper limits.This conclusion is subject to uncertainties associated with the halo mass. Ifdwarf spheroidal galaxies host local magnetic fields, the diffusion of theelectrons can result in a signal detectable by future X-ray telescopes.

On the use of X-ray and gamma-ray telescopes for identifying the origin of electrons and positrons observed by ATIC, Fermi, and PAMELA