Speaker
Description
A fundamental question regarding the Fermi Galactic Center Excess (GCE) is whether the underlying structure is point-like or smooth. This debate, often framed in terms of a millisecond pulsar or annihilating dark matter (DM) origin for the emission, awaits a conclusive resolution. We weigh in on the problem using graph-convolutional neural networks and estimate the fluxes of different emission components as well as the source-count distributions (SCDs) of the underlying point-source populations. We find a faint GCE described by a median SCD peaked at a flux of ∼ 4 × 10e−11 counts / cm^2 / s, which would require N ∼ O(10,000) sources to explain the entire excess (median value N = 29,300 across the sky). Although faint, this SCD allows us to derive the constraint ηP ≤ 66% for the dark matter-like Poissonian fraction of the GCE flux ηP at 95% confidence, suggesting that a substantial amount of the GCE flux is due to point-sources.
