The Extragalactic gamma-ray Emission (EGB) is constituted by two essential parts: resolved gamma-ray sources, point-like or extended, and an isotropic component. Once the formers have been excluded (masked or subtracted), what remains is the latter component, called Unresolved Gamma-Ray Background (UGRB), which, at a deeper level, is not truly isotropic and includes contribution from unresolved populations of sources. Expanding the UGRB sky map into spherical harmonics gives a powerful mean to study the intensity fluctuations even at the smallest scales, which can give clues about what this component is made of.
In this analysis we study the UGRB anisotropy signal with 8 years of Fermi-LAT Pass 8 data. An energy-dependent mask has been built to cover each resolved source in addiction to a region around the Galactic plane. Preliminary results are compatible with at least two classes of point-like sources contributing the UGRB emission.