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Dark matter annihilation into charged particles is necessarily accompanied bygamma rays, produced via radiative corrections. Internal bremsstrahlung fromthe final state particles can produce hard gamma rays up to the dark mattermass, with an approximately model-independent spectrum. Focusing onannihilation into electrons, we compute robust upper bounds on the dark matterself annihilation cross section $<\sigma_A v >_{e^+e^-}$ using gamma ray datafrom the Milky Way spanning a wide range of energies, $\sim10^{-3} - 10^4$ GeV.We also compute corresponding bounds for the other charged leptons. We makeconservative assumptions about the astrophysical inputs, and demonstrate howour derived bounds would be strengthened if stronger assumptions about theseinputs are adopted. The fraction of hard gamma rays near the endpointaccompanying annihilation to $e^+e^-$ is only a factor of $\alt 10^2$ lowerthan for annihilation directly to monoenergetic gamma rays. The bound on$<\sigma_A v >_{e^+e^-}$ is thus weaker than that for $<\sigma_A v>_{\gamma\gamma}$ by this same factor. The upper bounds on the annihilationcross sections to charged leptons are compared with an upper bound on the {\ittotal} annihilation cross section defined by neutrinos.

Gamma-ray Constraints on Dark Matter Annihilation into Charged Particles