A refined model of secondary photon emission from heavy WIMP annihilations in the Galactic Centre

Abstract

Heavy Weakly Interacting Massive Particles (WIMPs) remain a prominent yet less constrained dark matter (DM) candidate, with the Galactic Centre (GC) serving as a prime target for indirect detection via gamma-ray signals. Extending our previous work that highlighted the significance of secondary inverse Compton (IC) emission from annihilation-produced electrons, we expand the analysis to a broader range of WIMP masses and introduce a more realistic spatially-dependent modelling framework for the GC environment. This approach incorporates complexities such as the three-dimensional DM distribution, spatially varying radiation and magnetic fields, and electron transport mechanisms like Galactic winds and diffusion. We assess the impact of these environmental factors on both the spatial and spectral characteristics of the resulting secondary emissions. Our results demonstrate the robustness and necessity of incorporating this emission, and highlight its role in enhancing the prospects for detecting heavy WIMPs through observations of the inner Galaxy. We provide the resulting data products to the community to support future analyses and observational studies.