Dark matter searches with radio observations

We compute the radio synchrotron emission induced by WIMP DM annihilations inside our galaxy and in extragalactic halos. Comparing DM fluxes with radio surveys from 22 MHz to 1420 MHz we derive bounds on the WIMP paramer space. Light WIMPs, MDM ? 10 GeV, with thermal annihilation cross?sections (i.e. (?v) = 3 ? 10?26 cm3s?1) are strongly constrained, especially those candidates annihilating mainly into leptons. We then show that DM sources could account for a significant fraction of the extragalactic?radio emission inferred by the ARCADE?2 Collaboration. We argue that future telescopes with sensitives at ?Jy level will be particulary suitable to search for faint DM emissions. We show that future data on source counts and angular correlations could become relevant to distinguish DM signals from astrophysical sources, such as radio loud active galactic nuclei and star forming galaxies.