Main Image
Volume 312 - 7th International Fermi Symposium (IFS2017) - Session Extragalactic Diffuse Emission and Extragalactic Background Light
Study of the anisotropy of the unresolved gamma-ray background
M. Negro* on behalf of the Fermi-LAT Collaboration
*corresponding author
Full text: pdf
Published on: 2017 December 12
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.
Open Access
Creative Commons LicenseCopyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.