Speaker
Description
The GeV gamma-ray sky, as observed by the Fermi Large Area Telescope (Fermi LAT), harbors a plethora of localized point-like sources. At high latitudes ($|b|>30^{\circ}$), most of these sources are of extragalactic origin. The source-count distribution as a function of their flux, $\mathrm{d}N/\mathrm{d}S$, is a well-established quantity to summarize this population. We employ sequential simulation-based inference using the truncated marginal neural ratio estimation (TMNRE) algorithm on 12 years of Fermi-LAT data to infer the parameters of the $\mathrm{d}N/\mathrm{d}S$ distribution in this part of the sky for energies between 1 GeV and 10 GeV. While our approach allows us to cross-validate existing results in the literature, we demonstrate that we can go further than mere parameter inference. We derive a source catalogue of detected sources at high latitudes in terms of position and flux obtained from a self-consistently determined detection threshold based on the LAT's instrument response functions and utilized gamma-ray background models.
