Orateur
M.
Matthias Lorentz
(Irfu, CEA Saclay)
Description
Very high energy gamma rays (VHE, > 100 GeV) propagating over cosmological distances interact with the extragalactic background light (EBL) which is the second most intense background in the Universe after the cosmic microwave background. Observations of spectral features in the VHE band of extragalactic sources related to this energy-dependent absorption process with the H.E.S.S. array of Cherenkov telescopes allow for a unique model independent measurement of the EBL energy distribution, otherwise very difficult to determine.
Second order processes to the propagation of such extragalactic gamma rays can also be used to probe magnetic fields in cosmic voids or to test potential effects violating Lorentz invariance.
Auteur principal
M.
Matthias Lorentz
(Irfu, CEA Saclay)
