Constraining extragalactic background light from TeV blazars (Research Note)

Aims. Our goal is to research the upper limits to the extragalactic background light (EBL). Methods. The upper limits to the extragalactic background light (EBL) are presented, using the Fermi and very high energy (VHE) spectra recently observed in TeV blazars. We use an assumption that the VHE intrinsic photon index cannot be harder than the Fermi index measured by the Fermi-LAT. Results. These upper limits are compatible with ones given by most EBL models; however, the models of high EBL density are contradicted by TeV blazars.