  If dark matter decays into electrons and positrons, it can affect Galactic
radio emissions and the local cosmic ray fluxes. We propose a new, more general
analysis of constraints on dark matter. The constraints can be obtained for any
decaying dark matter model by convolving the specific dark matter decay
spectrum with a response function. We derive this response function from
full-sky radio surveys at 408 MHz, 1.42 GHz and 23 GHz, as well as from the
positron flux recently reported by PAMELA. We discuss the influence of
astrophysical uncertainties on the response function, such as from propagation
and from the profiles of the dark matter and the Galactic magnetic field. As an
application, we find that some widely used dark matter decay scenarios can be
ruled out under modest assumptions.
