Insights from LHAASO and IceCube into the origin of the Galactic diffuse TeV--PeV emission

Abstract

The high-energy diffuse gamma-ray emission and neutrino emission are expected from the Galactic plane, generated by hadronuclear interactions between cosmic rays (CR) and interstellar medium (ISM). Therefore, measurements of these diffuse emissions will provide important clues on the origin and nature of Galactic CRs. Comparing the latest observations of LHAASO and IceCube on the diffuse Galactic gamma-ray and neutrino emissions respectively, we suggest that the diffuse gamma-ray emission at multi-TeV energies contains a considerable contribution of a leptonic component. By modelling the gamma-ray halos powered by middle-aged pulsars in our Galaxy with taking into account the magnetic field configuration and the interstellar radiation field in the Galaxy, we demonstrate that the collective contribution of pulsar halos can account for the excess in the measured diffuse gamma-ray emission with respect to the predicted flux from CR-ISM interactions. The resulting one-dimensional profile along the Galactic longitude is also consistent with the observation.

28 pages, 13 figures; published in Nature Astronomy

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Cited by in corpus (19)

• Measurement of Very-high-energy Diffuse Gamma-ray Emissions from the Galactic Plane with LHAASO-WCDA
• On the Contribution of Unresolved Pulsars to the Ultra-high-energy Galactic Diffuse Gamma-Ray Emission
• Energy dependence of the knee in the cosmic ray spectrum across the Milky Way
• Imprints of PeV cosmic-ray sources on the diffuse gamma-ray emission
• A New Perspective on the Diffuse Gamma-Ray Emission Excess
• The Origin of the Very-High-Energy Diffuse $\gamma$-Ray Emission: The Case for Galactic Source Cocoons
• Mirages and Large TeV Halo-Pulsar Offsets from Cosmic Ray Propagation
• Cosmic Ray Diffusion in the Turbulent Interstellar Medium: Effects of Mirror Diffusion and Pitch Angle Scattering
• A discussion on the origin of the sub-PeV Galactic gamma-ray emission
• Absence of TeV halos around millisecond pulsars
• X-ray Binaries: a potential dominant contributor to the cosmic ray spectral knee structure
• Quantitative constraint on the contribution of resolved gamma-ray sources to the sub-PeV Galactic diffuse gamma-ray flux measured by the Tibet ASγ experiment
• Revisiting the propagation of highly-energetic gamma rays in the Galaxy
• PHECT: A lightweight computation tool for pulsar halo emission
• LHAASO Galactic Plane $\gamma$-rays Strongly Constrain Heavy Dark Matter
• Interpreting the LHAASO Galactic diffuse emission data
• The GPSP Atlas: High-resolution Galactic Photon Survival Probability Atlas for Very-High- and Ultra-High-Energy Gamma-Ray Astronomy
• TeV-PeV Gamma-ray and Neutrino Emission in the Galactic Plane
• Axion-like Particle Search with a Light-Shining-Through-Walls Setup at a $\gamma$-$\gamma$ Collider