Speaker
Description
Since its mission started more than 17 years ago, the Fermi Large Area Telescope (LAT) has significantly advanced our view of the GeV gamma-ray sky, yet several key questions remain - such as the nature of the isotropic diffuse background, the properties of the Galactic pulsar population, and the origin of the GeV excess towards the Galactic Centre. Addressing these challenges requires sophisticated astrophysical modelling and robust statistical methods capable of handling high-dimensional parameter spaces.
Building on our previous single-population, single-energy-bin analysis of Fermi-LAT data using simulation-based inference (SBI), we present a multi-bin spectral extension of the gamma-ray emission simulator. The updated framework simultaneously models two source populations, Galactic pulsars and extragalactic point sources, with distinct spatial distributions and intrinsic spectral variability informed by the empirical spread observed in detected members of each respective class. This richer forward model enables joint inference of population-level quantities on a per-class basis, including luminosity functions and source-count distributions. We present preliminary results that investigate the extent to which SBI can disentangle the two populations and recover their respective spectral and spatial properties from synthetic observations.