Origin of Galactic sub-PeV diffuse gamma-ray emission: Constraints from high-energy neutrino observations

Abstract

Very recently, diffuse gamma rays with $0.1\mathrm{PeV}<E_{\gamma }<1\mathrm{PeV}$ have been discovered from the Galactic disk by the Tibet air shower array and muon detector array (Tibet AS+MD array). While the measured sub-PeV flux may be compatible with the hadronic origin in the conventional Galactic cosmic ray propagation model, we find that it is in possible tension with the non-detection of Galactic neutrino emissions by the IceCube neutrino telescope. We further find that the presence of an extra cosmic ray component of relatively hard spectrum, which is probably related to the Cygnus Cocoon region and other PeV cosmic-ray sources in the Galactic disk, would alleviate the tension. This scenario implies the existence of an extreme accelerator of either protons or electrons beyond PeV in the Cygnus region, and predicts the continuation of the gamma-ray spectrum of Cygnus Cocoon up to 1 PeV with a possible hardening beyond $\sim 30-100$TeV.

arXiv comment8 pages, 5 figures, to appear in ApJ Letters

References in corpus (27)

• Energy spectra of gamma-rays, electrons and neutrinos produced at proton-proton interactions in the very high energy regime
• Fermi-LAT Observations of the Diffuse Gamma-Ray Emission: Implications for Cosmic Rays and the Interstellar Medium
• Time-integrated Neutrino Source Searches with 10 years of IceCube Data
• Global cosmic-ray related luminosity and energy budget of the Milky Way
• First Detection of sub-PeV Diffuse Gamma Rays from the Galactic Disk: Evidence for Ubiquitous Galactic Cosmic Rays beyond PeV Energies
• Klein-Nishina Effects in the Spectra of Non-Thermal Sources Immersed in External Radiation Fields
• Probing the Galactic Origin of the IceCube Excess with Gamma-Rays
• A radiation transfer model for the Milky-Way: I. Radiation fields and application to High Energy Astrophysics
• Constraints on Galactic Neutrino Emission with Seven Years of IceCube Data
• Gamma-ray sky points to radial gradients in cosmic-ray transport
• The Galactic Diffuse Gamma-ray Spectrum from Cosmic-ray Proton Interactions
• High-energy Cosmic Rays and Neutrinos from Semi-relativistic Hypernovae
• HAWC observations of the acceleration of very-high-energy cosmic rays in the Cygnus Cocoon
• Diffuse Galactic gamma ray flux at very high energy
• Study of the diffuse gamma-ray emission from the Galactic plane with ARGO-YBJ
• Evidence for TeV Gamma-Ray Emission from the Galactic Plane
• Sub-PeV Neutrinos from TeV Unidentified Sources in the Galaxy
• A Very High Energy $\gamma$-Ray Survey towards the Cygnus Region of the Galaxy
• Pulsar TeV Halos Explain the TeV Excess Observed by Milagro
• Observation of TeV gamma rays from the Cygnus region with the ARGO-YBJ experiment
• Dissecting the Cygnus Region with TeV Gamma Rays and Neutrinos
• Diffuse Neutrino and Gamma-ray Emissions of the Galaxy above the TeV
• Constraining the magnetic field in the TeV halo of Geminga with X-ray Observation
• Galactic diffuse gamma-ray emission at TeV energy
• Gamma-Ray Puzzles in Cygnus X: Implications for High-Energy Neutrinos
• Neutrino signal from extended Galactic sources in IceCube
• The diffuse GeV-TeV $\gamma$-ray emission of the Cygnus region

Cited by in corpus (20)

• Measurement of ultra-high-energy diffuse gamma-ray emission of the Galactic plane from 10 TeV to 1 PeV with LHAASO-KM2A
• Galactic diffuse gamma rays meet the PeV frontier
• Unresolved sources naturally contribute to PeV $\gamma$-ray diffuse emission observed by Tibet AS$\gamma$
• Galactic diffuse gamma-ray emission from GeV to PeV energies in light of up-to-date cosmic ray measurements
• Insights from LHAASO and IceCube into the origin of the Galactic diffuse TeV--PeV emission
• The Physics of Pulsar Halos: Research Progress and Prospect
• Where are Milky Way's Hadronic PeVatrons?
• Pion decay model of TIBET-AS$\gamma$ PeV gamma-ray signal
• Galactic gamma-ray and neutrino emission from interacting cosmic-ray nuclei
• Ultrahigh-energy diffuse gamma-ray emission from cosmic-ray interactions with medium surrounding acceleration sources
• Modeling of GeV-TeV gamma-ray emission of Cygnus Cocoon
• The LHAASO PeVatron bright sky: what we learned
• Constraints on the $e^{\pm }$ Pair Injection of Pulsar Halos: Implications from the Galactic Diffuse Multi-TeV Gamma-ray Emission
• Signatures of anisotropic diffusion around PeVatrons in 100 TeV gamma-ray data
• 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
• The GALPROP Cosmic-ray Propagation and Non-thermal Emissions Framework: Release v57
• Multi-messenger Implications of Sub-PeV Diffuse Galactic Gamma-Ray Emission
• First constraints on axion-like particles from Galactic sub-PeV gamma rays
• Constraining the position of the knee in the galactic cosmic ray spectrum with ultra-high-energy diffuse $\gamma$-rays
• TeV-PeV Gamma-ray and Neutrino Emission in the Galactic Plane