An excess of excesses examined via dark matter radio emissions from galaxies

Dark Matter Interpretations of the e± Excesses after FERMI

The cosmic-ray excess observed by PAMELA in the positron fraction and by FERMI and HESS in e− + e can be interpreted in terms of DM annihilations or decays into leptonic final states. Final states into τ ’s or 4μ give the best fit to the excess. However, in the annihilation scenario, they are incompatible with photon and neutrino constraints, unless DM has a quasi-constant density profile. Fina...

Decaying Dark Matter can explain the e± excesses

PAMELA and ATIC recently reported excesses in e± cosmic rays. Since the interpretation in terms of DM annihilations was found to be not easily compatible with constraints from photon observations, we consider the DM decay hypothesis and find that it can explain the e± excesses compatibly with all constraints, and can be tested by dedicated HESS observations of the Galactic Ridge. ATIC data indi...

Inverse Compton constraints on the Dark Matter e ± excesses

Recent results from experiments like PAMELA have pointed to excesses of e± in cosmic rays. If interpreted in terms of Dark Matter annihilations, they imply the existence of an abundant population of e± in the galactic halo at large. We consider the high energy gamma ray fluxes produced by Inverse Compton scattering of interstellar photons on such e±, and compare them with the available data fro...

Dark Matter in Elliptical Galaxies?

Dark Matter Halos around Galaxies

We present evidence that all galaxies, of any Hubble type and luminosity, bear the kinematical signature of a mass component distributed differently from the luminous matter. We review and/or derive the DM halo properties of galaxies of different morphologies: spirals, LSBs, ellipticals, dwarf irregulars and dwarf spheroidals. We show that the halo density profile Mh(x) = Mh(1) (1 + a ) x3 x2 +...