Intrinsic spectra of H.E.S.S. blazars : what would we see without EBL absorption

Intrinsic spectra of H.E.S.S. blazars : what would we see without EBL absorption Authors:Carlo Romoli, David Sanchez, Matthias Lorentz, Pierre Brun on behalf of the H.E.S.S. collaboration The vast majority of extragalactic sources detected in the very high energy (E> 200 GeV) are active galactic nuclei (AGN) located at cosmological distances. During their travel towards earth, the emitted gamma-rays suffer for absorption by the extragalatic background light (EBL). The density of the EBL is not very well constraint by direct or indirect measurement which leads to uncertainties on the intrisic spectrum of the sources. high-quality AGN’s spectra obtained with the High Energy Stereoscopic System (H.E.S.S.) have been used to perform a model-independent measurement of the EBL spectral energy distribution. While the precision of this measurement remains limited, it reflects the sensitivity of H.E.S.S. alone to the EBL and offers the possibility to access the intrinsic spectra of AGNs in a consistent manner, taking into account the derived uncertainties on the EBL spectral energy distribution. In this constribution, we study the intrinsic spectra as measured by H.E.S.S. and by the Fermi Large Area Telescope (LAT) of several blazars of the H.E.S.S. sky. This is then the opportunity to have an new insight in the emission processes at play in the jets of AGN. The data presented consist of monitoring data of quiecent state of blazars and also flares of bright objects, such as PKS 2155-304, Mrk 421, recorded by H.E.S.S.