Visualizing Multi-messenger Constraints


The rise in the energy spectrum of the positron ratio, observed by the PAMELA satellite above 10 GeV, and other cosmic ray measurements, have been interpreted as a possible signature of Dark Matter annihilation in the Galaxy. However, the large number of free parameters, and the large astrophysical uncertainties, make it difficult to do conclusive statements about the viability of this scenario. In a recent paper, Miguel Pato (PhD student at IAP), Lidia Pieri (postdoc at IAP) and I have performed a multi-wavelength, multi-messenger analysis, that combines in a consistent way the constraints arising from different astrophysical observations. We have shown that if standard assumptions are made for the distribution of Dark Matter (we build models on the recent Via Lactea II and Aquarius simulations) and the propagation of cosmic rays, current DM models cannot explain the observed positron flux without exceeding the observed fluxes of antiprotons or gamma-ray and radio photons. To visualize the multi-messenger constraints, we have introduced “star plots”, a graphical method that allows to show in the same plot theoretical predictions and observational constraints for different messengers and wavelengths.