The anisotropy of the Fermi-LAT extragalactic sky: still blazars.

We analyze the angular power spectrum (APS) of the unresolved gamma-ray background (UGRB) emission, and combine it with the measured properties of the resolved gamma-ray sources of the Fermi-LAT 4FGL catalog. Our goal is to dissect the composition of the gamma-ray sky and establish the relevance of different classes of source populations in determining the observed UGRB anisotropy level, especially at low energies. We find that, under physical assumptions for the spectral energy dispersion, two populations are required to fit APS data, namely flat spectrum radio quasars (FSRQ) at low energies and BL Lacs (BLL) at high energies. The inferred luminosity functions agree well with the extrapolation of the FSRQ and BLL ones obtained from the 4FLG catalog. Bounds on an additional gamma-ray emission due to annihilating dark matter are also derived.