N. Fornengo, R. A. Lineros, M. Regis, M. Taoso
Dark matter annihilations in the Galactic halo inject relativistic electrons
and positrons which in turn generate a synchrotron radiation when interacting
with the galactic magnetic field. We calculate the synchrotron flux for various
dark matter annihilation channels, masses, and astrophysical assumptions in the
low-frequency range and compare our results with radio surveys from 22 MHz to
1420 MHz. We find that current observations are able to constrain particle dark
matter with "thermal" annihilation cross-sections, i.e. (\sigma v) = 3 x 10^-26
cm^3/s, and masses M_DM < 10 GeV. We discuss the dependence of these bounds on
the astrophysical assumptions, namely galactic dark matter distribution, cosmic
rays propagation parameters, and structure of the galactic magnetic field.
Prospects for detection in future radio surveys are outlined.
View original:
http://arxiv.org/abs/1110.4337
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