Extragalactic gamma-ray background from AGN winds and star-forming galaxies in cosmological galaxy formation models

Understand

We derive the contribution to the extragalactic gamma-ray background (EGB) from AGN winds and star-forming galaxies by including a physical model for the gamma-ray emission produced by relativistic protons accelerated by AGN-driven and supernova-driven shocks into a state-of-the-art semi-analytic model of galaxy formation.

• This is based on galaxy interactions as triggers of AGN accretion and starburst activity and on expanding blast wave as the mechanism to communicate outwards the energy injected into the interstellar medium by the active nucleus.
• We compare the model predictions with the latest measurement of the EGB spectrum performed by the Fermi-LAT in the range between 100 MeV and 820 GeV.
• We find that AGN winds can provide ~35$\pm$15% of the observed EGB in the energy interval E_{\gamma}=0.1-1 GeV, for ~73$\pm$15% at E_{\gamma}=1-10 GeV, and for ~60$\pm$20% at E_{\gamma}>10 GeV.