Measurement of the EBL spectral energy distribution using the VHE gamma-ray spectra of H.E.S.S. blazars

Understand

Very high-energy gamma-rays (VHE, E>100 GeV) propagating over cosmological distances can interact with the low-energy photons of the extragalactic background light (EBL) and produce electron-positron pairs.

• The transparency of the universe to VHE gamma-rays is then directly related to the spectral energy distribution (SED) of the EBL.
• The observation of features in the VHE energy spectra of extragalactic sources allows the EBL to be measured, which otherwise is very difficult to determine.
• An EBL-model independent measurement of the EBL SED with the H.E.S.S.