Fitting formulae for photon spectra from WIMP annihilation
  Annihilation of different dark matter (DM) candidates into Standard Model
(SM) particles could be detected through their contribution to the gamma ray
fluxes that are measured on the Earth. The magnitude of such contributions
depends on the particular DM candidate, but certain imprints of produced photon
spectra may be analyzed in a model-independent fashion. In this work we provide
the fitting formulae for the photon spectra generated by WIMP annihilation into
quarks, leptons and gauge bosons channels in a wide range of WIMP masses.
