Dark matter signatures in the anisotropic radio sky

作者：Zhang Le^*; Sigl Guenter

来源：Journal of Cosmology and Astroparticle Physics, 2008, (9): 027.

DOI：10.1088/1475-7516/2008/09/027

• CMBR theory
• dark matter
• power spectrum

We calculate the intensity and the angular power spectrum of the cosmological background of synchrotron emission from cold dark matter annihilations into electron-positron pairs. We compare this background with the intensity and anisotropy of astrophysical and cosmological radio backgrounds, such as those from normal galaxies, radio galaxies and galaxy cluster accretion shocks, with the cosmic microwave background and with Galactic foregrounds. Under modest assumptions for the dark matter clustering we find that around 2 GHz average intensity and fluctuations of the radio background at sub-degree scales allow us to probe dark matter masses greater than or similar to 100 GeV and annihilation cross sections not far from the natural values similar to 3 x 10(-26) cm(3) s(-1) required to reproduce the correct relic density of thermal dark matter. The angular power spectrum of the signal from dark matter annihilation tends to be flatter than that from astrophysical radio backgrounds. Furthermore, radio source counts have comparable constraining power. Such signatures are interesting, especially for future radio detectors such as SKA.

• 出版日期2008-9