Speaker
Description
Recent results on the Extragalactic Background Light (EBL) intensity obtained from a combined likelihood analysis of blazar spectra detected by the MAGIC telescopes are reported. The EBL is the optical-infrared diffuse background light accumulated during galaxy evolution, directly and/or reprocessed by dust, which provides unique information about the history of galaxy formation. The low energy photons from the EBL may interact with very high energy (VHE, E > 100 GeV) photons from blazars. This interaction between the EBL and the gamma-ray photons leaves an energy-dependent imprint of the EBL on the VHE gamma-ray spectra of the blazars. Therefore, the study of their spectra can be used to constrain the EBL density at different wavelengths and its evolution in time. In the last few years the MAGIC telescopes obtained accurate measurements of the spectra of 12 blazars in the redshift range from z=0.03 to z=0.944 for over 300 hours of observation. This allows us to extend the redshift coverage and improve upon previous constraints on EBL, which turn out to be compatible with state-of-the-art models. We conclude that these new measurements are limited by systematic uncertainties.
