• monte carlo
• crpropa
• HESS J1943+213
• IGMF
• magnetic field
• galactic evolution
• fermi
• gamma
• astroparticle
• cosmology

Galactic magnetic field’s origin is unknown. The possible explanation for present-day observed values lies in the characteristic of the so-called seed fields and eventually in the amplification method. Two opposite schools for the magnetic field origin consist in the primordial origin of seed fields generated in the early universe phase transition and the possibility that magnetic fields are generated within the galaxies with astrophysical mechanisms. While primordial hypotheses predict a magnetic field in cosmic voids, astrophysical hypotheses don’t.
Measuring magnetic fields in cosmic voids with traditional magnetic field measurement techniques such as Zeeman splitting of degenerate level or faraday rotation of photons crossing magnetized regions owe to a magnetic field limit which is not constraining enough to rule out one or the other mechanism.
In this thesis, we measure the intergalactic magnetic field (IGMF) exploiting the deflection of secondary leptons generated in a cascade process due to the reactions happening in the intergalactic medium (IGM) to explain the non-detection of a cascade component in the Fermi-LAT band of the spectrum of the blazar HESS J1943-213. The IGMF is simulated with CRPropa 3.1.5 modified with a custom spectrum and the analysis is carried out with a dedicated python pipeline. The inferred value for the IGMF Root Mean Square is higher than ever before (3·10^-14 Gauss), mostly due to the better choiche of the source.