Fermi Gamma-ray Space Telescope

A GeV-TeV Measurement of the Extragalactic Background Light

Abhishek Desai
(Kari Helgason; Marco Ajello)

Abstract:

The Extragalactic Background Light (EBL) is the result of the collective emission of all sources over the history of the universe. A powerful technique to study the EBL is through the imprint it leaves  in the spectra of distant gamma-ray sources via the photon-photon interaction. Recently we have performed an outstanding measurement of the EBL using 9 years of Fermi-LAT data. We have complemented this dataset with TeV data from ground telescopes (HESS, MAGIC, and VERITAS) allowing us to extend the range of the EBL constraints to cover the infrared regime. In this talk, we present this first homogenous measurement of the EBL covering the UV, optical and IR.