Sensitivity of gamma-ray telescopes for detection of magnetic fields in intergalactic medium

TL;DR

This paper investigates how current and future gamma-ray telescopes can detect weak intergalactic magnetic fields by using techniques like extended emission observation and time delay analysis, potentially constraining cosmic magnetic field theories.

Contribution

It demonstrates that gamma-ray observations can probe key magnetic field parameters, enabling tests of their origins and primordial existence.

Findings

Gamma-ray telescopes can constrain magnetic field origin theories.

Observation techniques can probe most of the relevant parameter space.

Potential to discover or rule out primordial magnetic fields.

Abstract

We explore potential of current and next-generation gamma-ray telescopes for the detection of weak magnetic fields in the intergalactic medium. We demonstrate that using two complementary techniques, observation of extended emission around point sources and observation of time delays in gamma-ray flares, one would be able to probe most of the cosmologically and astrophysically interesting part of the "magnetic field strength" vs. "correlation length" parameter space. This implies that gamma-ray observations with Fermi and ground-based Cherenkov telescopes will allow to (a) strongly constrain theories of the origin of magnetic fields in galaxies and galaxy clusters and (b) discover, constrain or rule out the existence of weak primordial magnetic field generated at different stages of evolution of the Early Universe.