Related papers: Galactic diffuse gamma-ray emission at TeV energy
We show from a simulations-based study of the TACTIC telescope that fractal and wavelet analysis of Cerenkov images, recorded in a single imaging Cerenkov telescope, enables almost complete segregation of isotropic gamma-ray initiated…
Ultrahigh energy protons and nuclei from extragalactic cosmic ray sources initiate intergalactic electromagnetic cascades, resulting in observable fluxes of $\gamma$-rays in the GeV-TeV energy domain. The total spectrum of such cascade…
Galaxy clusters can be sources of high-energy (HE) $\gamma$-ray radiation, due to the efficient acceleration of particles exceeding EeV energies. At present, though, the only candidate for emitting HE $\gamma$-rays is the Coma cluster,…
Cosmic Rays (CRs) propagating through dense molecular clouds (MCs) produce gamma rays which carry direct information about the CR distribution throughout the Galaxy. Observations of gamma rays in different energy bands allow exploration of…
We have performed an analysis of the diffuse gamma-ray emission with the Fermi Large Area Telescope in the Milky Way Halo region searching for a signal from dark matter annihilation or decay. In the absence of a robust dark matter signal,…
The synergy between the Fermi-LAT and ground-based Cherenkov telescope arrays gives us the opportunity for the first time to characterize the high-energy emission from blazars over 5 decades in energy, from 100 MeV to 10 TeV. In this study,…
RX J1713.7-3946 is the brightest shell-type Supernova remnant (SNR) of the TeV gamma-ray sky. Earlier Fermi-LAT results on low-energy gamma-ray emission suggested that, despite large uncertainties in the background determination, the…
The measurement of diffuse PeV gamma-ray emission from the Galactic plane would provide information about the energy spectrum and propagation of Galactic cosmic rays, and the detection of a point-like source of PeV gamma rays would be…
At TeV energies, the gamma-ray horizon of the universe is limited to redshifts z<<1, and, therefore, any observation of TeV radiation from a source located beyond z=1 would call for a revision of the standard paradigm. While robust…
We report the observation of a very high energy \gamma-ray source, whose position is coincident with HESS J1841-055. This source has been observed for 4.5 years by the ARGO-YBJ experiment from November 2007 to July 2012. Its emission is…
The LHAASO collaboration has recently released the spectrum and the angular distribution of the gamma-ray Galactic diffuse emission from 1 TeV to 1 PeV measured with the Kilometer-2 Array (KM2A) and the Water Cherenkov Detector Array…
In this work, we revisit the all-sky Galactic diffuse $\gamma$-ray emission taking into account the new measurements of cosmic ray electron/positron spectrum by PAMELA, ATIC and Fermi, which show excesses of cosmic electrons/positrons…
The observations of high energy $\gamma$-ray emission from the Galactic center (GC) by HESS, and recently by Fermi, suggest the cosmic ray acceleration in the GC and possibly around the supermassive black hole. In this work we propose a…
The cosmic gamma-ray background radiation is one of the most fundamental observables in the gamma-ray band. Although the origin of the cosmic gamma-ray background radiation has been a mystery for a long time, the Fermi gamma-ray space…
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…
Westerlund 1 (Wd 1) is the most massive stellar cluster in the Galaxy and associated with an extended region of TeV emission. Here we report the results of a search for GeV gamma-ray emission in this region. The analysis is based on ~4.5…
An anomalous emission component at energies of a few GeV and located towards the inner Galaxy is present in the Fermi-LAT data. It is known as the Fermi-LAT GeV excess. Using almost 8 years of data we reanalyze the characteristics of this…
We report on observations of TeV-selected AGN made during the first 5.5 months of observations with the Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope (Fermi). In total, 96 AGN were selected for study, each being…
Galaxy clusters are one of the prime sites to search for dark matter (DM) annihilation signals. Depending on the substructure of the DM halo of a galaxy cluster and the cross sections for DM annihilation channels, these signals might be…
The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope provides both direct and indirect measurements of Galactic cosmic rays (CR). The LAT high-statistics observations of the 7 GeV - 1 TeV electron plus positron spectrum and…