Constraints on Dark Matter Annihilation from Starlight-Induced Inverse Compton Emission in Omega Centauri

The search for the particle identity of dark matter (DM) remains one of the foremost challenges in modern physics. In this work, we derive new constraints on the DM annihilation cross section σv by considering the inverse Compton (IC) scattering of DM annihilation injected e+e- off the starlight radiation field in Omega Centauri. As a likely remnant core of a dwarf galaxy, Omega Centauri provides a dense stellar environment that enhances the predict IC signal. Using multi-wavelength observations from Chandra and Fermi-LAT, we establish upper limits on σv over a wide DM mass range from MeV to TeV. Notably, in the tens-of-MeV range, our results surpass existing constraints by approximately two orders of magnitude, exceeding σv about 10-31 cm cubed,s-1. At several GeV to the TeV DM masses range, our constraints also remain stronger than existing limits. Our results demonstrate that starlight induced IC emission is an important component for indirect DM searches in dense stellar systems, establishing Omega Centauri as a powerful probe of the nature of DM.