What VHE gamma-ray astronomy can do about the IGMF

Intergalactic space is believed to contain non-zero Magnetic fields (the Intergalactic Magnetic Field: IGMF) at scales of Mpc (the coherence length). It would be originated and amplified from pre-existing fields during the gravitational collapse of forming structures in the early Universe. There is no direct detection/evidence of the IGMF so, there is no certain information about its intensity and spatial properties. Very high energy (VHE >100 GeV) gamma rays coming from blazars can produce electron-positron pairs when interacting with the Extragalactic Background Light and the Cosmic Microwave Background, initiating an intergalactic electromagnetic cascade. The spatial development of the charged component of this cascade is presumably affected by the IGMF, resulting in an extended isotropic emission of photons around the source (halo), or in a broadening of the emission beam, depending on the intensity of this field and the source distance. These effects on the source flux can be registered by Cherenkov telescope systems and analyzed to study the IGMF. In this presentation I will describe the methods being used to study the IGMF analyzing actual data from current instruments and using simulations for future instruments in the area.