Constraining the astrophysical origin of intergalactic magnetic fields

Understand

High-energy photons can produce electron-positron pairs upon interacting with the extragalactic background light (EBL).

• These pairs will in turn be deflected by the intergalactic magnetic field (IGMF), before possibly up-scattering photons of the cosmic microwave background (CMB), thereby initiating an electromagnetic cascade.
• The non-observation of an excess of GeV photons and an extended halo around individual blazars due to this electromagnetic cascade can be used to constrain the properties of the IGMF.
• In this work, we use publicly available data of 1ES 0229+200 by Fermi LAT and H.E.S.S.