Related papers: Imaging Atmospheric Cerenkov Telescopes: Technique…
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…
Atmospheric air Cherenkov telescopes are successfully used for ground-based, very high-energy (VHE) gamma ray astronomy. Triggers from the so-called single muon and other long-flying relativistic charged particle events are an unwanted…
Recently the AGILE $\gamma$-ray telescope has reported the enhanced $\gamma$-ray emission above 100 MeV from the direction of the Crab Nebula during a period of a few days. This intriguing observation has been confirmed by the Fermi-LAT…
We suggest a new approach to study the cosmis ray (CR) mass composition in the energy region from 30 TeV/nucleus up to the "knee" region, i.e. up to a few PeV/nucleus, using an array of imaging atmospheric Cherenkov telescopes (IACTs) of a…
Very High Energy (VHE) gamma rays and charged cosmic rays (CCRs) provide an observational window into the acceleration mechanisms of extreme astrophysical environments. One of the major challenges at Imaging Air Cherenkov Telescopes (IACTs)…
Molecular clouds act as primary targets for cosmic-ray interactions and are expected to shine in gamma-rays as a by-product of these interactions. Indeed several detected gamma-ray sources both in HE and VHE gamma-rays (HE: 100 MeV < E <…
The physics of the non-thermal Universe provides information on the acceleration mechanisms in extreme environments, such as black holes and relativistic jets, neutron stars, supernovae or clusters of galaxies. In the presence of magnetic…
The recent discovery of TeV emission from gamma-ray bursts (GRBs) by the MAGIC and H.E.S.S. Cherenkov telescopes confirmed that emission from these transients can extend to very high energies. The TeV energy domain reaches the most…
The recent IceCube publication claims the observation of cosmic neutrinos with energies down to $\sim 10$ TeV, reinforcing the growing evidence that the neutrino flux in the 10-100 TeV range is unexpectedly large. Any conceivable source of…
A long standing problem in high energy astrophysics is the nature of galactic accelerators of particles with energies above PeV. Such objects are sources of galactic cosmic rays and can produce PeV-regime photons observed by ground-based…
We present TeV gamma-ray observations of the Crab Nebula, the standard reference source in ground-based gamma-ray astronomy, using data from the High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory. In this analysis we use two…
Despite the enormous efforts done in very recent years, both theoretically and experimentally, the basic three questions about the cosmic rays origin remain without clear answers: what are their sources, how are they accelerated, how do…
Cherenkov radiation enables high-energy particle identification through its velocity-dependent emission angle, yet conventional detectors fail to detect momenta beyond tens of GeV/c owing to the absence of natural materials with near-unity…
Intriguing evidence has been accumulating for the production of cosmic rays in the Cygnus region of the Galactic plane. We here show that the IceCube experiment can produce incontrovertible evidence for cosmic ray acceleration by observing…
Blazars are potential candidates of cosmic-ray acceleration up to ultrahigh energies ($E\gtrsim10^{18}$ eV). For an efficient cosmic-ray injection from blazars, $p\gamma$ collisions with the extragalactic background light (EBL) and cosmic…
Observations with the current generation of very-high-energy gamma-ray telescopes have revealed an astonishing variety of particle accelerators in the Milky Way, such as supernova remnants, pulsar wind nebulae, and binary systems. The…
Using the HEGRA system of imaging atmospheric Cherenkov telescopes, one quarter of the Galactic plane (-2 deg < l < 85 deg) was surveyed for TeV gamma-ray emission from point sources and moderately extended sources (diameter <= 0.8 deg).…
Usually the Imaging Atmospheric Cherenkov Telescopes, used for the ground-based gamma-ray astronomy in the very high energy range 50 GeV - 50 TeV, perform air shower observations till the zenith angle of ~60 deg. Beyond that limit the…
The quest for the origin of cosmic ray (CRs) is a fundamental issue in astrophysics. Shocks of supernova remnants (SNRs) have been considered as the dominant contributors to Galactic CRs below the spectral knee near $\sim 3$…
Detection of delayed sub-TeV photons from Gamma-Ray Bursts (GRBs) by MAGIC and HESS has proven the promising future of GRB afterglow studies with the Cherenkov Telescope Array (CTA), the next-generation gamma-ray observatory. With the…