Speaker
Manuel Meyer
(University of Hamburg)
Description
Very high energy (VHE) gamma-rays undergo pair production
with low energy photons of background radiation fields.
This leads to an attenuation of the primary gamma-ray flux of extragalactic sources
in the interaction with the extragalactic background light
which stretches from ultraviolet to far-infrared wavelengths.
In the presence of magnetic fields, gamma-rays could oscillate into hypothetical
axion-like particles (ALPs).
This might lead to a reduced opacity of the Universe for VHE gamma-rays,
as ALPs circumvent pair production.
Here, the impact of photon-ALP conversions on blazar spectra
in different magnetic-field configurations is presented.
Possible photon-ALP couplings are derived
if evidences of a low opacity of the Universe for VHE gamma-rays
are interpreted within ALP scenarios.
Primary author
Manuel Meyer
(University of Hamburg)
Co-author
Prof.
Dieter Horns
(Institut für Experimentalphysik, Univeristy of Hamburg)
