Search for Extended γ-ray Emission around AGN with H.E.S.S. and Fermi-LAT

Abstract

Context: Very-high-energy (VHE; E>100 GeV) γ-ray emission from blazars inevitably gives rise to electron-positron pair production through the interaction of these γ-rays with the Extragalactic Background Light (EBL). Depending on the magnetic fields in the proximity of the source, the cascade initiated from pair production can result in either an isotropic halo around an initially beamed source or a magnetically broadened cascade flux. Aims: Both extended pair halo (PH) and magnetically broadened cascade (MBC) emission from regions surrounding the blazars 1ES 1101-232, 1ES 0229+200 and PKS 2155-304 were searched for, using VHE γ-ray data taken with the High Energy Stereoscopic System (H.E.S.S.), and high energy (HE; 100 MeV<E<100 GeV) γ-ray data with the Fermi Large Area Telescope (LAT). Methods: By comparing the angular distributions of the reconstructed gamma-ray events to the angular profiles calculated from detailed theoretical models, the presence of PH and MBC was investigated. Results: Upper limits on the extended emission around 1ES 1101-232, 1ES 0229+200 and PKS 2155-304 are found to be at a level of few percent of the Crab nebula flux above 1 TeV, depending on the assumed photon index of the cascade emission. Assuming strong Extra-Galactic Magnetic Field (EGMF) values, > 10${}^{-12}$G, this limits the production of pair halos developing from electromagnetic cascades. For weaker magnetic fields, in which electromagnetic cascades would result in magnetically broadened cascades, EGMF strengths in the range (0.3 - 3)$\times 10^{-15}$G were excluded for PKS 2155-304 at the 99% confidence level, under the assumption of a 1 Mpc coherence length.

11 pages, 6 figures. Accepted for publication by Astronomy & Astrophysics

References in corpus (4)

• Observations of the Crab Nebula with H.E.S.S
• Lower limit on the strength and filling factor of extragalactic magnetic fields
• New constraints on the Mid-IR EBL from the HESS discovery of VHE gamma rays from 1ES 0229+200
• Simultaneous observations of PKS 2155-304 with H.E.S.S., Fermi, RXTE and ATOM: spectral energy distributions and variability in a low state

Cited by in corpus (47)

• Search for Spatial Extension in High-Latitude Sources Detected by the Fermi Large Area Telescope
• The NuSTAR view on Hard-TeV BL Lacs
• Progress in unveiling extreme particle acceleration in persistent astrophysical jets
• A lower bound on intergalactic magnetic fields from time variability of 1ES 0229+200 from MAGIC and Fermi/LAT observations
• Leptonic and Hadronic Radiative Processes in Supermassive-Black-Hole Jets
• Search for Magnetically Broadened Cascade Emission From Blazars with VERITAS
• Gamma-ray observations of blazars and the intergalactic magnetic field spectrum
• ASTRI Mini-Array Core Science at the Observatorio del Teide
• Sensitivity of the Cherenkov Telescope Array to the detection of axion-like particles at high gamma-ray opacities
• Constraints on the intergalactic magnetic field using Fermi-LAT and H.E.S.S. blazar observations
• Magnetogenesis around the first galaxies: the impact of different field seeding processes on galaxy formation
• The Impact of Plasma Instabilities on the Spectra of TeV Blazars
• Implications of a Primordial Magnetic Field for Magnetic Monopoles, Axions, and Dirac Neutrinos
• Characterization of the Inner Knot of the Crab: The Site of the Gamma-ray Flares?
• Probing Quantum Gravity with Imaging Atmospheric Cherenkov Telescopes
• Electromagnetic cascade masquerade: a way to mimic $\gamma$--axion-like particle mixing effects in blazar spectra
• Multimessenger Constraints on Intergalactic Magnetic Fields from the Flare of TXS 0506+056
• Ultrahigh-energy cosmic ray interactions as the origin of very high energy $\gamma -$rays from BL Lacs
• Physics of cosmological cascades and observable properties
• Morphology of blazar-induced gamma ray halos due to a helical intergalactic magnetic field
• Axion driven cosmic magneto-genesis during the QCD crossover
• Sensitivity of the Cherenkov Telescope Array to the Detection of Intergalactic Magnetic Fields
• Bow Ties in the Sky I: The Angular Structure of Inverse Compton Gamma-ray Halos in the Fermi Sky
• Patchy blazar heating: diversifying the thermal history of the intergalactic medium
• Dark Matter Minihalos from Primordial Magnetic Fields
• Can we constrain the extragalactic magnetic field from very high energy observations of GRB 190114C?
• Primordial magnetic fields: consistent initial conditions and impact on high-z structures
• Extragalactic Observatory Science with the ASTRI Mini-Array at the Observatorio del Teide
• Bow Ties in the Sky II: Searching for Gamma-ray Halos in the Fermi Sky Using Anisotropy
• Modelling the propagation of very-high-energy gamma rays with the CRbeam code: Comparison with CRPropa and ELMAG codes
• Constraints on the extragalactic magnetic field strength from blazar spectra based on 145 months of Fermi-LAT observations
• Proton Synchrotron Radiation from Extended Jets of PKS 0637-752 and 3C 273
• On conservative models of "the pair-production anomaly" in blazar spectra at Very High Energies
• Search of the pair echo signatures in the high-energy light curve of GRB190114C
• Constraints on Primordial Magnetic Fields from the Lyman-α forest
• Observable spectral and angular distributions of $\gamma$-rays from extragalactic ultrahigh energy cosmic ray accelerators: the case of extreme TeV blazars
• Observing the Energetic Universe at Very High Energies with the VERITAS Gamma Ray Observatory
• Matter power spectrum induced by primordial magnetic fields: from the linear to the non-linear regime
• Gamma-ray counterparts of 2WHSP high-synchrotron-peaked BL Lac objects as possible signatures of ultra-high-energy cosmic-ray emission
• Probing the IGMF with the next generation Cherenkov telescopes
• Prospects for detection of the pair-echo emission from TeV gamma-ray bursts
• Nonthermal Radiation of the Extreme TeV Blazar 1ES 0229+200 from Electromagnetic Cascades on Infrared Photon Field
• Can WIMPs Survive the Legacy of a Magnetised Early Universe?
• Cascade Model of an Anomaly in Blazar Spectra at Very High Energy
• Testing models of extragalactic $\gamma$-ray propagation using observations of extreme blazars in GeV and TeV energy ranges
• Ensemble fluctuations of the cosmic ray energy spectrum and the intergalactic magnetic field
• The impact of plasma instability cooling on intergalactic magnetic field constraints in GeV cascades for optimized instability cooling parameters