Constraints on annihilating dark matter in the Omega Centauri cluster

Abstract

Recent gamma-ray and radio studies have obtained some stringent constraints on annihilating dark matter properties. However, only a few studies have focussed on using X-ray data to constrain annihilating dark matter. In this article, we perform the X-ray analysis of annihilating dark matter using the data of the Omega Centauri cluster. If dark matter is the correct interpretation of the non-luminous mass component derived in the Omega Centauri cluster, the conservative lower limits of thermal dark matter mass annihilating via the $\tau^+\tau^-$, $b\bar{b}$ and $W^+W^-$ channels can be significantly improved to 104(43) GeV, 650(167) GeV and 480(137) GeV respectively, assuming the diffusion coefficient $D_0 \le 10^{26}(10^{27})$ cm$^2$/s. These constraints can safely rule out the recent claims of dark matter interpretation of the gamma-ray excess and anti-proton excess seen in our Galaxy. Generally speaking, the conservative lower limits obtained for non-leptophilic annihilation channels are much more stringent than that obtained by gamma-ray analysis of nearby dwarf galaxies. We anticipate that this would open a new window for constraining annihilating dark matter.