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

Abstract

Motivated by the difference between the fluxes of sub-PeV Galactic diffuse gamma-ray emission (GDE) measured by the Tibet AS$\gamma$ experiment and the LHAASO collaboration, our study constrains the contribution to the GDE flux measured by Tibet AS$\gamma$ from the sub-PeV gamma-ray sources in the first LHAASO catalog plus the Cygnus Cocoon. After removing the gamma-ray emission of the sources masked in the observation by Tibet AS$\gamma$, the contribution of the sources to the Tibet diffuse flux is found to be subdominant; in the sky region of $25^{\circ }<l<100^{\circ }$ and $|b|<5^{\circ }$, it is less than 26.9% $\pm$ 9.9%, 34.8% $\pm$ 14.0%, and ${13.5%}^{+6.3%}_{-7.7%}$ at 121 TeV, 220 TeV, and 534 TeV, respectively. In the sky region of $50^{\circ }<l<200^{\circ }$ and $|b|<5^{\circ }$, the fraction is less than 24.1% $\pm$ 9.5%, 27.1% $\pm$ 11.1% and ${13.5%}^{+6.2%}_{-7.6%}$. After subtracting the source contribution, the hadronic diffusive nature of the Tibet diffuse flux is the most natural interpretation, although some contributions from very faint unresolved hadronic gamma-ray sources cannot be ruled out. Different source-masking schemes adopted by Tibet AS$\gamma$ and LHAASO for their diffuse analyses result in different effective galactic latitudinal ranges of the sky regions observed by the two experiments. Our study concludes that the effect of the different source-masking schemes leads to the observed difference between the Tibet diffuse flux measured in $25^{\circ }<l<100^{\circ }$ and $|b|<5^{\circ }$ and LHAASO diffuse flux in $15^{\circ }<l<125^{\circ }$ and $|b|<5^{\circ }$.

The manuscript has been accepted for publication from The Astrophysical Journal Letters

References in corpus (35)

• Fermi-LAT Observations of the Diffuse Gamma-Ray Emission: Implications for Cosmic Rays and the Interstellar Medium
• The H.E.S.S. Galactic plane survey
• Variable Very High Energy Gamma-ray Emission from the Microquasar LS I +61 303
• The 2HWC HAWC Observatory Gamma Ray Catalog
• Observation of high-energy neutrinos from the Galactic plane
• The First LHAASO Catalog of Gamma-Ray Sources
• Milagro Observations of Multi-TeV Emission from Galactic Sources in the Fermi Bright Source List
• First Detection of sub-PeV Diffuse Gamma Rays from the Galactic Disk: Evidence for Ubiquitous Galactic Cosmic Rays beyond PeV Energies
• A Measurement of the Spatial Distribution of Diffuse TeV Gamma Ray Emission from the Galactic Plane with Milagro
• Observation of Extended VHE Emission from the Supernova Remnant IC 443 with VERITAS
• Very high energy particle acceleration powered by the jets of the microquasar SS 433
• Measurement of ultra-high-energy diffuse gamma-ray emission of the Galactic plane from 10 TeV to 1 PeV with LHAASO-KM2A
• HAWC observations of the acceleration of very-high-energy cosmic rays in the Cygnus Cocoon
• Diffuse Galactic gamma ray flux at very high energy
• Identification of the TeV Gamma-ray Source ARGO J2031+4157 with the Cygnus Cocoon
• Observation of VHE gamma-rays from Cassiopeia A with the MAGIC telescope
• Morphological and spectral properties of the W51 region measured with the MAGIC telescopes
• An Ultrahigh-energy $\gamma$-ray Bubble Powered by a Super PeVatron
• Gamma-ray observations of Tycho's SNR with VERITAS and Fermi
• Detection of Extended VHE Gamma Ray Emission from G106.3+2.7 with VERITAS
• Periastron Observations of TeV Gamma-Ray Emission from a Binary System with a 50-year Period
• Detection of Very High Energy radiation from HESS J1908+063 confirms the Milagro unidentified source MGRO J1908+06
• Spatially Resolving the Very High Energy emission from MGRO J2019+37 with VERITAS
• Spectrum and Morphology of the Two Brightest Milagro Sources in the Cygnus Region: MGRO J2019+37 and MGRO J2031+41
• Discovery of TeV Gamma-ray Emission Toward Supernova Remnant SNR G78.2+2.1
• The supernova remnant W49B as seen with H.E.S.S. and Fermi-LAT
• Unresolved sources naturally contribute to PeV $\gamma$-ray diffuse emission observed by Tibet AS$\gamma$
• Discovery of VHE $\gamma$-ray emission from the SNR G54.1+0.3
• Discovery of TeV gamma-ray emission from the pulsar wind nebula 3C 58 by MAGIC
• Insights from LHAASO and IceCube into the origin of the Galactic diffuse TeV--PeV emission
• Origin of Galactic sub-PeV diffuse gamma-ray emission: Constraints from high-energy neutrino observations
• Decomposing the Origin of TeV-PeV Emission from the Galactic Plane: Implications of Multi-messenger Observations
• MAGIC reveals a complex morphology within the unidentified gamma-ray source HESS J1857+026
• Discovery of TeV $\gamma$-ray emission from the neighbourhood of the supernova remnant G24.7+0.6 by MAGIC
• On the Contribution of Unresolved Pulsars to the Ultra-high-energy Galactic Diffuse Gamma-Ray Emission

Cited by in corpus (2)

• A discussion on the origin of the sub-PeV Galactic gamma-ray emission
• X-ray Binaries: a potential dominant contributor to the cosmic ray spectral knee structure