Oct 15 – 20, 2017
Congress Center Garmisch-Partenkirchen
Europe/Berlin timezone
The proceedings of the 7th Fermi Symposium are available at https://pos.sissa.it/312/

The Density of Blazars above 100 MeV and the Origin of the Extragalactic Gamma-ray Background

Oct 19, 2017, 2:45 PM
GaPa/1-1 - Olympiasaal (Garmisch-Partenkirchen)

GaPa/1-1 - Olympiasaal


Contributed talk Extragalactic Diffuse & EBL Extragalactic diffuse & EBL II


lea marcotulli (clemson university)


Relying on the first 104 months of Fermi-LAT Pass 8 data, using detailed Monte Carlo simulations, we obtained the most sensitive measurement of the source count distribution of blazars above 100 MeV. The result shows, with high statistical significance, the presence of a break in the distribution at low fluxes. From this, we provide a precise measurement of the contribution of blazars to the extragalactic gamma-ray background (EGB). Furthermore, we confirm that they can not account for the total EGB, therefore, another source class is required to explain the remaining component. In this talk, we will present this new measurement and discuss alternatives for the origin of the missing EGB component.

Primary author

lea marcotulli (clemson university)

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