Related papers: Contribution of unresolved point sources to the ga…
Published EGRET spectra from blazars extend only to 10 GeV, yet EGRET has detected approximately 2000 gamma-rays above 10 GeV of which about half are at high Galactic latitude. We report a search of these high-energy gamma-rays for…
We report the discovery of a soft gamma ray source, namely IGR J18135-1751, detected with the IBIS imager on board the INTEGRAL satellite. The source is persistent and has a 20-100 keV luminosity of $\sim$5.7 $\times$ 10$^{34}$ erg s$^{-1}$…
HESS J1857+026 is an extended TeV gamma-ray source discovered by H.E.S.S. very close to the Galactic plane. Located in the vicinity of the pulsar PSR J1856+0245, the source represents a pulsar wind nebula (PWN) candidate. In Fermi-LAT data,…
The H.E.S.S. experiment, an array of four Imaging Atmospheric Cherenkov Telescopes with high sensitivity and large field-of-view, has been used to search for emitters of very-high-energy (VHE, >100 GeV) gamma-rays along the Galactic plane,…
The latest High Altitude Water Cherenkov (HAWC) point-like source catalog up to 56 TeV reported the detection of two sources in the region of the Galactic plane at galactic longitude 52\deg < l < 55\deg, 3HWC J1930+188 and 3HWC J1928+178.…
Context. The diffuse TeV gamma-ray emission detected in the inner $\sim$ 100 pc of the Galactic Center suggests the existence of a central cosmic-ray accelerator reaching $\sim$ PeV energies. It is interesting to associate this so-called…
The origin and acceleration mechanism of cosmic rays (CRs) remain fundamental open questions. Galaxy mergers are proposed as very high-energy CR accelerators, which are expected to produce high-energy (HE) $\gamma$ rays and neutrinos…
A 50 ksec Chandra observation of the unidentified TeV source in Cygnus reported by the HEGRA collaboration reveals no obvious diffuse X-ray counterpart. However, 240 Pointlike X-ray sources are detected within or nearby the extended TeV…
Recent results from Pierre Auger Observatory, showing energy dependent chemical composition of ultrahigh-energy cosmic rays (UHECRs) with a growing fraction of heavy elements at high energies, suggest a possible non-negligible contribution…
The riddle of the origin of Cosmic Rays is open since one century. Recently we got the experimental proof of hadronic acceleration in Supernovae Remnants, however new questions rised and no final answer has been provided so far. Gamma ray…
This paper reports the results from three targeted searches of Milagro TeV sky maps: two extragalactic point source lists and one pulsar source list. The first extragalactic candidate list consists of 709 candidates selected from the…
We investigated the MeV properties of 173 unidentified or only tentatively identified EGRET sources listed in the third EGRET catalogue, by analyzing the simultaneously collected COMPTEL MeV data for each individual source. The sources can…
For distant extragalactic sources of gamma-rays in the PeV energy range, interactions of the gamma rays with intergalactic diffuse radiation fields will initiate a pair cascade. Depending on the magnetic fields in the vicinity of the…
In light of the recent IceCube evidence for a flux of extraterrestrial neutrinos, we revisit the prospect of observing the sources of the Galactic cosmic rays. In particular, we update the predictions for the neutrino flux expected from…
The H.E.S.S. collaboration has reported a high-energy spherically symmetric diffuse gamma-ray emission in the inner 50 pc of the Milky Way, up to ~ 50 TeV. Here we propose a leptonic model which provides an alternative to the hadronic…
At the end of the EGRET mission, only 6-8 Galactic sources had been identified as young pulsars. Since then, several energetic pulsars have been discovered in EGRET error boxes along the Galactic plane, as well as several pulsar wind…
Photons with very high energy up to TeV (VHE) emitted from active galactic nuclei (AGNs) provide some invaluable information of the origin of $\gam$-ray emission. Although 66 blazars have been detected by {\it EGRET}, only three low…
We investigate the physical nature and origin of the gamma-ray emission from the extended source HESS J1841-055 observed at TeV and GeV energies. We observed HESS J1841-055 at TeV energies for a total effective time of 43 hours with the…
Very high energy gamma-rays probe the long-standing mystery of the origin of cosmic rays. Produced in the interactions of accelerated particles in astrophysical objects, they can be used to image cosmic particle accelerators. A first…
The Galactic center is an interesting region for high-energy (0.1-100 GeV) and very-high-energy (E > 100 GeV) gamma-ray observations. Potential sources of GeV/TeV gamma-ray emission have been suggested, e.g., the accretion of matter onto…