Non-thermal X-rays from the Ophiuchus galaxy cluster and dark matter annihilation

TL;DR

This paper explores whether dark matter annihilation can explain the non-thermal X-ray and radio emissions from the Ophiuchus galaxy cluster, proposing that inverse Compton scattering of annihilation products accounts for observed signals.

Contribution

It introduces a model linking dark matter annihilation to observed non-thermal emissions in galaxy clusters and predicts how future gamma-ray observations can test this hypothesis.

Findings

Dark matter annihilation can produce electrons and positrons explaining X-ray and radio emissions.

A magnetic field of about 0.1 microGauss is consistent with the observed emissions.

Future observations by GLAST can confirm or refute the dark matter origin of these signals.

Abstract

We investigate a scenario where the recently discovered non-thermal hard X-ray emission from the Ophiuchus cluster originates from inverse Compton scattering of energetic electrons and positrons produced in weakly interacting dark matter pair annihilations. We show that this scenario can account for both the X-ray and the radio emission, provided the average magnetic field is of the order of 0.1 microGauss. We demonstrate that GLAST will conclusively test the dark matter annihilation hypothesis. Depending on the particle dark matter model, GLAST might even detect the monochromatic line produced by dark matter pair annihilation into two photons.