Decomposing the Origin of TeV-PeV Emission from the Galactic Plane: Implications of Multi-messenger Observations

Abstract

High-energy neutrino and $\gamma$-ray emission has been observed from the Galactic plane, which may come from individual sources and/or diffuse cosmic rays. We evaluate the contribution of these two components through the multimessenger connection between neutrinos and $\gamma$ rays in hadronic interactions. We derive maximum fluxes of neutrino emission from the Galactic plane using $\gamma$-ray catalogs, including 4FGL, HGPS, 3HWC, and 1LHAASO, and measurements of the Galactic diffuse emission by Tibet AS$\gamma$ and LHAASO. We find that the IceCube Galactic neutrino flux is larger than the contribution from all resolved sources when excluding promising leptonic sources such as pulsars, pulsar wind nebulae, and TeV halos. Our result indicates that the Galactic neutrino emission is likely dominated by the diffuse emission by the cosmic-ray sea and unresolved hadronic $\gamma$-ray sources. In addition, the IceCube flux is comparable to the sum of the flux of non-pulsar sources and the LHAASO diffuse emission especially above 30 TeV. This implies that the LHAASO diffuse emission may dominantly originate from hadronic interactions, either as the truly diffuse emission or unresolved hadronic emitters. Future observations of neutrino telescopes and air-shower $\gamma$-ray experiments in the Southern hemisphere are needed to accurately disentangle the source and diffuse emission of the Milky Way.

9+3 pages, 4+2 figures, 0+2 tables, accepted for publication in ApJL

References in corpus (16)

• HI4PI: A full-sky HI survey based on EBHIS and GASS
• Incremental Fermi Large Area Telescope Fourth Source Catalog
• Extended gamma-ray sources around pulsars constrain the origin of the positron flux at Earth
• Observation of high-energy neutrinos from the Galactic plane
• First Detection of sub-PeV Diffuse Gamma Rays from the Galactic Disk: Evidence for Ubiquitous Galactic Cosmic Rays beyond PeV Energies
• Cosmic-ray propagation with DRAGON2: I. numerical solver and astrophysical ingredients
• Measurement of ultra-high-energy diffuse gamma-ray emission of the Galactic plane from 10 TeV to 1 PeV with LHAASO-KM2A
• Absorption of Very High Energy Gamma Rays in the Milky Way
• The Hunt for Pevatrons: The Case of Supernova Remnants
• Galactic diffuse gamma rays meet the PeV frontier
• Diffuse Emission of Galactic High-Energy Neutrinos from a Global Fit of Cosmic Rays
• Evidence for PeV Proton Acceleration from Fermi-LAT Observations of SNR G106.3+2.7
• Where are Milky Way's Hadronic PeVatrons?
• TeV emission of Galactic plane sources with HAWC and H.E.S.S
• High-Energy Neutrino Signatures of Newborn Pulsars In the Local Universe
• Galactic and Extragalactic Analysis of the Astrophysical Muon Neutrino Flux with 12.3 years of IceCube Track Data

Cited by in corpus (17)

• Insights from LHAASO and IceCube into the origin of the Galactic diffuse TeV--PeV emission
• Measurement of Very-high-energy Diffuse Gamma-ray Emissions from the Galactic Plane with LHAASO-WCDA
• The origin of high-energy astrophysical neutrinos: new results and prospects
• Astroparticles from X-ray Binary Coronae
• On the Contribution of Unresolved Pulsars to the Ultra-high-energy Galactic Diffuse Gamma-Ray Emission
• Probing the Galactic neutrino flux at neutrino energies above 200 TeV with the Baikal Gigaton Volume Detector
• 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
• 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
• Estimatingthe Contribution of Galactic Neutrino Sources
• Revisiting the propagation of highly-energetic gamma rays in the Galaxy
• 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
• Search for neutrino signals correlated with LHAASO diffuse Galactic emission
• TeV-PeV Gamma-ray and Neutrino Emission in the Galactic Plane
• Particle Astrophysics with High and Ultrahigh Energy Neutrinos