Radio signal constraints on galactic dark matter annihilation

Annihilation of Dark Matter usually produces together with gamma rays comparable amounts of electrons and positrons. The e⁺e^- gyrating in the galactic magnetic field then produce secondary synchrotron radiation which thus provides an indirect mean to constrain the DM signal itself. To this purpose, we calculate the radio emission from the galactic halo as well as from its expected substructures and we then compare it with the measured diffuse radio background. We employ a multi-frequency approach using data in the relevant frequency range 100 MHz-100 GHz, as well as the WMAP Haze data at 23 GHz. The derived constraints are of the order 〈σ _A^v〉=10^-24cm³s^-1 for a DM mass m_κ=100GeV even though sensibly depending on the astrophysical uncertainties.