Related papers: LHAASO sensitivity for diffuse gamma-ray signals f…
As one of the brightest galactic ${\gamma}$-ray sources, the Cygnus Cocoon superbubble has been observed by many detectors, such as $Fermi$-LAT, ARGO, HAWC, and LHAASO. However, the origin of $\gamma$-ray emission for the Cygnus Cocoon and…
The recent detection of TeV gamma-rays from the microquasar LS 5039 by HESS is one of the most exciting discoveries of observational gamma-ray astronomy in the very high energy regime. This result clearly demonstrates that X-ray binaries…
Given that gamma rays with energies larger than TeV are severely absorbed by background radiation fields, for many extragalactic sources, the GeV-TeV gamma-ray observations are the messengers that are closest in energy to the TeV-PeV…
We report the discovery of a UHE gamma-ray source, LHAASO J2108+5157, by analyzing the LHAASO-KM2A data of 308.33 live days. Significant excess of gamma-ray induced showers is observed in both energy bands of 25-100 TeV and $\gt$100 TeV…
We study the properties of the diffuse gamma-ray background around the Galactic plane at energies 20 -- 200 GeV. We find that the spectrum of this emission possesses significant spacial variations with respect to the average smooth…
Progress in the Imaging Atmospheric Cherenkov Technique has enabled first sensitive observations of the innermost few 100 pc of the Milky Way in Very High Energy (VHE; >100 GeV) gamma rays. Observations by the H.E.S.S. instrument deliver…
We consider decaying dark matter with masses $10^{7} \lesssim M \lesssim 10^{16}$ GeV, as a source of ultra-high energy (UHE) gamma rays. Using recent limits on UHE gamma-ray flux for energies $E_\gamma > 2 \cdot 10^{14}$ eV, provided by…
In the next decades, ultra-high-energy neutrinos in the EeV energy range will be potentially detected by next-generation neutrino telescopes. Although their primary goals are to observe cosmogenic neutrinos and to gain insight into extreme…
Dark matter could decay into Standard Model particles producing neutrinos directly or indirectly. The resulting flux of neutrinos from these decays could be detectable at neutrino telescopes and would be associated with massive celestial…
The large-scale diffuse $\gamma-$ray flux observed by Fermi-LAT in the 1-100 GeV energy range, parameterized as $\propto E^{-\Gamma}$, has a spectral index $\Gamma$ that depends on the distance from the Galactic center. This feature, if…
The recent detection of $\gamma$-rays with energy up to 10 TeV from dense regions surrounding some Supernova Remnants (SNR) provides strong, though still not conclusive, evidence that the nucleonic component of galactic Cosmic Rays is…
The bulk of the diffuse galactic gamma-ray emission above a few tens of GeV has been conventionally ascribed to the decay of neutral pions produced in cosmic-ray interactions with interstellar matter. Cosmic-ray electrons may, however, make…
We observed the bright unidentified TeV gamma-ray source HESS J1616-508 with the X-ray Imaging Spectrometers onboard the Suzaku satellite. No X-ray counterpart was found to a limiting flux of 3.1e-13 erg/s/cm^2 in the 2--10 keV band, which…
The H.E.S.S. experiment, an array of four Imaging Atmospheric Cherenkov Telescopes, observes the Galactic Centre (GC) region in the very high-energy (VHE, E > 100 GeV) domain since 2003. The GC is believed to be the region with the highest…
Particle acceleration in the inner ~ 200 pc of the Galaxy is discussed, where diffuse TeV gamma-rays have been detected by the High Energy Stereoscopic System (HESS) observation. The diffuse gamma-ray emission has a strong correlation with…
Recent observations, particularly from the HESS Collaboration, have revealed rich Galactic populations of TeV gamma-ray sources, including a collection unseen in other wavelengths. Many of these gamma-ray spectra are well measured up to ~10…
Extensive air shower detectors of gamma rays in the sub-PeV energy region provide a new and relatively unexplored window for dark matter searches. Here we derive some implications of the recently published Tibet AS$_\gamma$ data for…
The fraction of the contribution from yet-unresolved gamma-ray sources in the Galactic diffuse gamma rays observed by the Tibet air shower array is an important key to interpreting recent multi-messenger observations. This paper shows a…
Diffuse ultrahigh energy gamma-radiation can arise from a variety of astrophysical sources, including the interaction of extremely high energy cosmic rays with the 3K microwave background radiation or the collapse of topological defects…
It is assumed that heavy dark matter particles (HDMs) with a mass of O(TeV) are captured by the Sun. HDMs can decay to relativistic light dark matter particles (LDMs), which could be measured by km$^3$ neutrino telescopes (like the IceCube…