On the detectability of cosmic ray electron spectral features in the microwave/mm-wave range

Recent measurements of cosmic ray electron energy spectra suggest that above 10 GeV there may be deviations from a single power law spectrum. There are hints (ATIC) for a bump occurring between 100 GeV and 1TeV, meaning that there might be more high energy electrons than expected. Whether these electrons are produced within pulsar magnetospheres, or due to Dark Matter annihilation or decay, this is still matter of debate. Understanding the nature of these ultra high energy particles is a difficult task that can be fulfilled using all the available astrophysical observables. We investigate how different energy spectra produce different observable manifestations in the radio/microwave/mm-wave domain, where corresponding deviations from a synchrotron power law could appear. We raise the question around the detectability of these possible radio spectral features, which may be interesting for a wide scientific community including astrophysicists and scientists working on foregrounds removal for CMB experiments.