Cosmological Radio Emission induced by WIMP Dark Matter

TL;DR

This paper analyzes radio signals from WIMP dark matter in extragalactic halos, exploring their potential to constrain dark matter properties through next-generation radio surveys.

Contribution

It provides a comprehensive calculation of radio emissions from WIMP dark matter, including clustering effects and astrophysical uncertainties, and assesses their detectability and constraints.

Findings

Dark matter-induced radio sources can be significant at microJansky flux levels.

Next-generation radio surveys can probe WIMP properties via faint source counts.

Constraints on dark matter properties are competitive with other indirect detection methods.

Abstract

We present a detailed analysis of the radio synchrotron emission induced by WIMP dark matter annihilations and decays in extragalactic halos. We compute intensity, angular correlation, and source counts and discuss the impact on the expected signals of dark matter clustering, as well as of other astrophysical uncertainties as magnetic fields and spatial diffusion. Bounds on dark matter microscopic properties are then derived, and, depending on the specific set of assumptions, they are competitive with constraints from other indirect dark matter searches. At GHz frequencies, dark matter sources can become a significant fraction of the total number of sources with brightness below the microJansky level. We show that, at this level of fluxes (which are within the reach of the next-generation radio surveys), properties of the faint edge of differential source counts, as well as angular correlation data, can become an important probe for WIMPs.