Synchrotron Emission from Dark Matter Annihilation: Predictions for Constraints from Non-detections of Galaxy Clusters with New Radio Surveys

TL;DR

This paper predicts how upcoming radio surveys can constrain dark matter annihilation models by detecting or ruling out synchrotron radiation from electrons produced in galaxy clusters.

Contribution

It provides forecasts for constraints on dark matter annihilation cross sections from non-detections in future radio surveys of galaxy clusters.

Findings

LOFAR, ASKAP, and APERTIF surveys could rule out thermal relic dark matter models for masses below 100 GeV.

Non-detections in these surveys will significantly constrain dark matter annihilation cross sections.

Massive galaxy clusters are promising targets for detecting synchrotron signals from dark matter annihilation.

Abstract

The annihilation of dark matter particles is expected to yield a broad radiation spectrum via the production of Standard Model particles in astrophysical environments. In particular, electrons and positrons from dark matter annihilation produce synchrotron radiation in the presence of magnetic fields. Galaxy clusters are the most massive collapsed structures in the universe, and are known to host $\sim\mu$G-scale magnetic fields. They are therefore ideal targets to search for, or to constrain the synchrotron signal from dark matter annihilation. In this work we use the expected sensitivities of several planned surveys from the next generation of radio telescopes to predict the constraints on dark matter annihilation models which will be achieved in the case of non-detections of diffuse radio emission from galaxy clusters. Specifically, we consider the Tier 1 survey planned for the Low Frequency Array (LOFAR) at 120 MHz, the EMU survey planned for the Australian Square Kilometre Array Pathfinder (ASKAP) at 1.4 GHz, and planned surveys for APERTIF at 1.4 GHz. We find that, for massive clusters and dark matter masses $\lesssim 100$ GeV, the predicted limits on the annihilation cross section would rule out vanilla thermal relic models for even the shallow LOFAR Tier 1, ASKAP, and APERTIF surveys.