[GA118] New predictions for the very-high-energy gamma-ray sky
We present a phenomenological model of cosmic-ray (CR) transport based on inhomogeneous diffusion. Our model is strongly motivated and driven by the large-scale trends on proton normalization and slope inferred by Fermi-LAT gamma-ray data. In particular, the model provides a solution to the long-standing gradient problem in the outer Galactic plane, i.e. the tension between the observed radial profile of the hadronic gamma-ray emissivity and the standard model predictions, derived under the common assumptions of a steeply declining CR source distribution in the outer Galaxy, and homogeneous CR transport. We present our predictions for the very-high-energy interstellar gamma-ray emission, with particular focus on the multi-TeV domain, based on this CR propagation scenario. We discuss both the hadronic and leptonic contributions. For the Inverse Compton emission, we consider different models for the electron distribution — including a 3D description of the spiral-arm pattern of the Galaxy — and for the interstellar radiation field. Our model can be extensively tested against the current and forthcoming data from the HAWC and CTA collaborations, and will be useful for point-source studies in a wide energy range.