SKA sensitivity for possible radio emission from dark matter in Omega Centauri

Abstract

Omega Centauri, the largest known globular cluster in the Milky Way, is believed to be the remains of a dwarf galaxy's core. Giving its potential abundance of dark matter (DM), it is an attractive target for investigating the nature of this elusive substance in our local environment. Our study demonstrates that by observing Omega Centauri with the SKA for 100 hours, we can detect synchrotron radio or Inverse Compton (IC) emissions from the DM annihilation products. It enables us to constrain the cross-section of DM annihilation down to ∼ 10-30 cm3 s-1 for DM mass from several GeV to 100 GeV, which is much stronger compared with other observations. Additionally, we explore the axion, another well-motivated DM candidate, and provide stimulated decay calculations. It turns out that the sensitivity can reach g aγγ ∼ 10-10 GeV-1 for 2 × 10-7 eV< ma < 2 × 10-4 eV.