Bow Ties in the Sky II: Searching for Gamma-ray Halos in the Fermi Sky Using Anisotropy

Abstract

Many-degree-scale gamma-ray halos are expected to surround extragalactic high-energy gamma ray sources. These arise from the inverse Compton emission of an intergalactic population of relativistic electron/positron pairs generated by the annihilation of >100 GeV gamma rays on the extragalactic background light. These are typically anisotropic due to the jetted structure from which they originate or the presence of intergalactic magnetic fields. Here we propose a novel method for detecting these inverse-Compton gamma-ray halos based upon this anisotropic structure. Specifically, we show that by stacking suitably defined angular power spectra instead of images it is possible to robustly detect gamma-ray halos with existing Fermi Large Area Telescope (LAT) observations for a broad class of intergalactic magnetic fields. Importantly, these are largely insensitive to systematic uncertainties within the LAT instrumental response or associated with contaminating astronomical sources.

Submitted to ApJ, 22 pages, 27 figures, 9 pages in appendix

References in corpus (14)

• An Observational Determination of the Bolometric Quasar Luminosity Function
• The spectrum of isotropic diffuse gamma-ray emission between 100 MeV and 820 GeV
• The Spectrum of the Isotropic Diffuse Gamma-Ray Emission Derived From First-Year Fermi Large Area Telescope Data
• 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
• A hadronic origin for ultra-high-frequency-peaked BL Lac objects
• Observations of Mkn 421 with the MAGIC Telescope
• Cosmological Magnetic Field: a fossil of density perturbations in the early universe
• The duty cycle of local radio galaxies
• The Effect of Nonlinear Landau Damping on Ultrarelativistic Beam Plasma Instabilities
• The Linear Instability of Dilute Ultrarelativistic $e^{\pm }$ Pair Beams
• Importance of resolving the spectral support of beam-plasma instabilities in simulations
• Bow Ties in the Sky I: The Angular Structure of Inverse Compton Gamma-ray Halos in the Fermi Sky
• Probing stochastic inter-galactic magnetic fields using blazar-induced gamma ray halo morphology

Cited by in corpus (11)

• Progress on Cosmological Magnetic Fields
• The Gamma-Ray Window to Intergalactic Magnetism
• Missing Gamma-ray Halos and the Need for New Physics in the Gamma-ray Sky
• Growth of beam-plasma instabilities in the presence of background inhomogeneity
• The growth of the longitudinal beam-plasma instability in the presence of an inhomogeneous background
• The role of resonant plasma instabilities in the evolution of blazar induced pair beams
• Suppression of the TeV pair-beam plasma instability by a tangled weak intergalactic magnetic field
• Constraints on the Intergalactic Magnetic Field from Bow Ties in the Gamma-ray Sky
• Energy Dissipation in Strong Collisionless Shocks: The Crucial Role of Ion-to-Electron Scale Separation in Particle-in-Cell Simulations
• Constraining blazar heating with the 2<z<3 Lyman-$\alpha$ forest
• Simulations of Astrophysically Relevant Pair Beam Instabilities in a Laboratory Context