Probing the Intergalactic Magnetic Field with the Anisotropy of the Extragalactic Gamma-ray Background

Abstract

The intergalactic magnetic field (IGMF) may leave an imprint on the angular anisotropy of the extragalactic gamma-ray background through its effect on electromagnetic cascades triggered by interactions between very high energy photons and the extragalactic background light. A strong IGMF will deflect secondary particles produced in these cascades and will thus tend to isotropize lower energy cascade photons, thereby inducing a modulation in the anisotropy energy spectrum of the gamma-ray background. Here we present a simple, proof-of-concept calculation of the magnitude of this effect and demonstrate that current Fermi data already seem to prefer non-negligible IGMF values. The anisotropy energy spectrum of the Fermi gamma-ray background could thus be used as a probe of the IGMF strength.

11 pages, 4 figures, MN LaTeX style; accepted for publication in MNRAS

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Cited by in corpus (15)

• Cosmological Magnetic Fields: Their Generation, Evolution and Observation
• Constraints on the Intergalactic Magnetic Field with Gamma-Ray Observations of Blazars
• The Gamma-Ray Window to Intergalactic Magnetism
• The Extragalactic Gamma-ray Sky in the Fermi era
• The Star-Forming Galaxy Contribution to the Cosmic MeV and GeV Gamma-Ray Background
• The TeV Diffuse Cosmic Neutrino Spectrum and the Nature of Astrophysical Neutrino Sources
• Fermi-LAT gamma-ray anisotropy and intensity explained by unresolved Radio-Loud Active Galactic Nuclei
• Electromagnetic cascade masquerade: a way to mimic $\gamma$--axion-like particle mixing effects in blazar spectra
• Predicting the redshift of gamma-ray loud AGNs using supervised machine learning
• Predicting the redshift of gamma-ray loud AGNs using Supervised Machine Learning: Part 2
• Mean Energy Density of Photogenerated Magnetic Fields Throughout the Epoch of Reionization
• Impact of Plasma Instability on Constraint of the Intergalactic Magnetic Field
• Redshift prediction of Fermi-LAT gamma-ray sources using CatBoost gradient boosting decision trees
• On conservative models of "the pair-production anomaly" in blazar spectra at Very High Energies
• Diffuse Pionic Gamma-Ray Emission from Large Scale Structures in the FERMI Era