Characterizing γ-ray maps of the Galactic Center with neural density estimation

Machine learning methods have enabled new ways of performing inference on high-dimensional datasets modeled using complex simulations. We leverage recent advancements in simulation-based inference in order to characterize the contribution of various modeled components to γ-ray data of the Galactic Center recorded by the Fermi satellite. A specific goal here is to differentiate "smooth" emission, as expected for a dark matter origin, from more "clumpy" emission expected for a population of relatively bright, unresolved astrophysical point sources. Compared to traditional techniques based on the statistical distribution of photon counts, our method based on density estimation using normalizing flows is able to utilize more of the information contained in a given model of the Galactic Center emission, and in particular can perform posterior parameter estimation while accounting for pixel-to-pixel spatial correlations in the γ-ray map.