Bow Ties in the Sky I: The Angular Structure of Inverse Compton Gamma-ray Halos in the Fermi Sky

Abstract

Extended inverse Compton halos are generally anticipated around extragalactic sources of gamma rays with energies above 100 GeV. These result from inverse Compton scattered cosmic microwave background photons by a population of high-energy electron/positron pairs produced by the annihilation of the high-energy gamma rays on the infrared background. Despite the observed attenuation of the high-energy gamma rays, the halo emission has yet to be directly detected. Here, we demonstrate that in most cases these halos are expected to be highly anisotropic, distributing the up-scattered gamma rays along axes defined either by the radio jets of the sources or oriented perpendicular to a global magnetic field. We present a pedagogical derivation of the angular structure in the inverse Compton halo and provide an analytic formalism that facilitates the generation of mock images. We discuss exploiting this fact for the purpose of detecting gamma-ray halos in a set of companion papers.

Accepted by ApJ, 18 pages, 17 figures, 13 pages in appendix

References in corpus (6)

• Modeling the Emission Processes in Blazars
• Lower limit on the strength and filling factor of extragalactic magnetic fields
• The Imprint of The Extragalactic Background Light in the Gamma-Ray Spectra of Blazars
• The duty cycle of local radio galaxies
• Joint anisotropy and source count constraints on the contribution of blazars to the diffuse gamma-ray background
• The Effect of Nonlinear Landau Damping on Ultrarelativistic Beam Plasma Instabilities

Cited by in corpus (6)

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• Suppression of the TeV pair-beam plasma instability by a tangled weak intergalactic magnetic field
• Constraining blazar heating with the 2<z<3 Lyman-$\alpha$ forest
• Energy Dissipation in Strong Collisionless Shocks: The Crucial Role of Ion-to-Electron Scale Separation in Particle-in-Cell Simulations
• Simulations of Astrophysically Relevant Pair Beam Instabilities in a Laboratory Context