Diffuse Galactic gamma-ray emission with H.E.S.S

Abstract

Diffuse $\gamma$-ray emission is the most prominent observable signature of celestial cosmic-ray interactions at high energies. While already being investigated at GeV energies over several decades, assessments of diffuse $\gamma$-ray emission at TeV energies remain sparse. After completion of the systematic survey of the inner Galaxy, the H.E.S.S. experiment is in a prime position to observe large-scale diffuse emission at TeV energies. Data of the H.E.S.S. Galactic Plane Survey are investigated in regions off known $\gamma$-ray sources. Corresponding $\gamma$-ray flux measurements were made over an extensive grid of celestial locations. Longitudinal and latitudinal profiles of the observed $\gamma$-ray fluxes show characteristic excess emission not attributable to known $\gamma$-ray sources. For the first time large-scale $\gamma$-ray emission along the Galactic Plane using imaging atmospheric Cherenkov telescopes has been observed. While the background subtraction technique limits the ability to recover modest variation on the scale of the H.E.S.S. field of view or larger, which is characteristic of the inverse Compton scatter-induced Galactic diffuse emission, contributions of neutral pion decay as well as emission from unresolved $\gamma$-ray sources can be recovered in the observed signal to a large fraction. Calculations show that the minimum $\gamma$-ray emission from ${\pi }^0$-decay represents a significant contribution to the total signal. This detection is interpreted as a mix of diffuse Galactic $\gamma$-ray emission and unresolved sources.

8 pages, 2 figures, accepted for publication in Physical Review D

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Cited by in corpus (71)

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• Limits on Dark Matter Annihilation Signals from the Fermi LAT 4-year Measurement of the Isotropic Gamma-Ray Background
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• Measurement of ultra-high-energy diffuse gamma-ray emission of the Galactic plane from 10 TeV to 1 PeV with LHAASO-KM2A
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• Boosted Dark Matter in IceCube and at the Galactic Center
• Study of the diffuse gamma-ray emission from the Galactic plane with ARGO-YBJ
• Characterising the VHE diffuse emission in the central 200 parsecs of our Galaxy with H.E.S.S
• Population study of Galactic supernova remnants at very high $\gamma$-ray energies with H.E.S.S.
• Heavy right-handed neutrino dark matter and PeV neutrinos at IceCube
• KASCADE-Grande Limits on the Isotropic Diffuse Gamma-Ray Flux between 100 TeV and 1 EeV
• Pulsar TeV Halos Explain the TeV Excess Observed by Milagro
• Hint for a TeV neutrino emission from the Galactic Ridge with ANTARES
• WIMP searches with gamma rays in the Fermi era: challenges, methods and results
• Galactic diffuse gamma rays meet the PeV frontier
• A deep spectromorphological study of the $\gamma$-ray emission surrounding the young massive stellar cluster Westerlund 1
• Gamma rays as probes of cosmic-ray propagation and interactions in galaxies
• TeV Gamma-ray Observations of The Galactic Center Ridge By VERITAS
• Hunting for Heavy Winos in the Galactic Center
• Search for TeV Gamma-Ray Emission from Point-like Sources in the Inner Galactic Plane with a Partial Configuration of the HAWC Observatory
• Modelling the Galactic very-high-energy $\gamma$-ray source population
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• Insights from LHAASO and IceCube into the origin of the Galactic diffuse TeV--PeV emission
• TeV emission of Galactic plane sources with HAWC and H.E.S.S
• Measurement of Very-high-energy Diffuse Gamma-ray Emissions from the Galactic Plane with LHAASO-WCDA
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• Starburst galaxies as seen by gamma-ray telescopes
• Milky Way as a Neutrino Desert Revealed by IceCube Galactic Plane Observation
• Probing galactic cosmic ray distribution with TeV gamma-ray sky
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• LHAASO sensitivity for diffuse gamma-ray signals from the Galaxy
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• High-Statistics Measurement of the Cosmic-Ray Electron Spectrum with H.E.S.S
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• Ultra-High-Energy Gamma-Ray Astronomy
• Sensitivity of the Cherenkov Telescope Array to TeV photon emission from the Large Magellanic Cloud
• Prospects for a survey of the Galactic plane with the Cherenkov Telescope Array
• The Steady-State Multi-TeV Diffuse Gamma-Ray Emission Predicted with GALPROP and Prospects for the Cherenkov Telescope Array
• Galactic center gamma-ray production by cosmic rays from stellar winds and Sgr A East
• Mind the gap: The discrepancy between simulation and reality drives interpretations of the Galactic Center Excess
• Lower Bound on the Cosmic TeV Gamma-ray Background Radiation
• Intergalactic medium rotation measure of primordial magnetic fields
• Broadband X-ray Spectroscopy of the Pulsar Wind Nebula in HESS J1640-465
• Connecting direct and indirect detection with a dark spike in the cosmic-ray electron spectrum
• The Making of Catalogues of Very-High-Energy γ-ray Sources
• Setting an upper limit for the total TeV neutrino flux from the disk of our Galaxy
• A multi-messenger study of the total galactic high-energy neutrino emission
• Search for decaying heavy dark matter in an effective interaction framework: a comparison of $\gamma$-ray and radio observations
• The Origin of the Very-High-Energy Diffuse $\gamma$-Ray Emission: The Case for Galactic Source Cocoons
• Modeling the Galactic center gamma-ray emission with more realistic cosmic-ray dynamics
• Exploring the high energy frontiers of the Milky Way with ground-based gamma-ray astronomy: PeVatrons and the quest for the origin of Galactic cosmic-rays
• Mapping large-scale diffuse gamma-ray emission in 10-100 TeV band with Cherenkov telescopes
• Detecting and characterizing pulsar haloes with the Cherenkov Telescope Array
• Sensitivity of the Cherenkov Telescope Array to a dark matter signal from the Galactic centre
• Ultra High Energy Neutrino Event KM3-230213A as a Signal of Electroweak Vacuum Turbulence in Merging Black Hole Binaries
• Prospects on high-energy source searches based on pattern recognition: Object detection in the H.E.S.S. Galactic Plane Survey and catalogue cross-matches
• Gamma-Ray Astronomy from the Ground
• Search for neutrino signals correlated with LHAASO diffuse Galactic emission
• Probing Galactic Diffuse TeV Gamma-Ray Emission with the HAWC Observatory
• H.E.S.S.: The High Energy Stereoscopic System
• Probing the Dark Matter of Three-loop Radiative Neutrino Mass Generation Model with the Cherenkov Telescope Array
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• Predicting the Neutrino Emission for the Sources in the H.E.S.S. Galactic Plane Survey
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