TO: SEMINARIO DI FISICA ASTROPARTICELLARE:RADIO CONSTRAINTS ON DARK MATTER ANNIHILATION IN THE GALACTIC HALO AND ITS SUBSTRUCTURES
SESZIONE DI TORINO Annihilation of Dark Matter usually produces together with gamma rays
comparable amounts of electrons and positrons. The e+e- gyrating in the
galactic magnetic field then produce secondary synchrotron radiation which
thus provides an indirect mean to constrain the DM signal itself. To this
purpose, we calculate the radio emission from the galactic halo as well as
from its expected substructures and we then compare it with the measured
diffuse radio background. We employ a multi-frequency approach using data
in the relevant frequency range 100 MHz-100 GHz, as well as the WMAP haze
at 23 GHz. The derived constraints are of the order = 10^{-24}
cm^3s^{-1} for a DM mass m = 100 GeV sensibly depending however on the
astrophysical uncertainties, in particular on the assumption on the
galactic magnetic field model. The signal from single bright clumps is
instead largely attenuated by diffusion effects and offers only poor
prospects of detection.
DATA: 20-11-2008
Istituto Nazionale di Fisica
Nucleare - Piazza dei Caprettari, 70 -
00186 Roma
tel. +39 066840031 - fax +39 0668307924 - email: presidenza@presid.infn.it