Related papers: Ultra-high energy Inverse Compton emission from Ga…
The high-energy radiation from short period binaries containing a massive star with a compact relativistic companion was detected from radio to TeV gamma rays. We show here that PeV regime protons can be efficiently accelerated in the…
Astronomy at the highest energies observed must be performed by studying neutrinos rather than photons because the universe is opaque to photons of these energies. By making observations of neutrinos with energies above 10 EeV one can…
We investigate, in terms of production from pulsars and their nebulae, the cosmic ray positron and electron fluxes above $\sim10$ GeV, observed by the AMS-02 experiment up to 1 TeV. We concentrate on the Vela-X case. Starting from the…
M87 is the first extragalactic source detected in the TeV gamma-ray domain that is not a blazar, its large scale jet not being aligned to the line of sight. We present here a multi-blob synchrotron self-Compton model accounting explicitly…
The most common progenitors of gamma-ray bursts (GRBs) are massive stars with strong stellar winds. We show that the GRB blast wave in the wind should emit a bright GeV flash. It is produced by inverse Compton cooling of the thermal plasma…
Very high energy (VHE) gamma-ray emission from a distant source (z >~0.2) can be efficiently absorbed my means of the electron-positron pair creation process. Analyses of the unabsorbed spectra imply that the intrinsic TeV emission of some…
Air-Cherenkov telescopes have detected pulsations at energies above 50 GeV from a growing number of Fermi pulsars. These include the Crab, Vela, PSR B1706-44 and Geminga, with the first two having pulsed detections above 1 TeV. In some…
Data of Pierre Auger Observatory show a proton-dominated chemical composition of ultrahigh-energy cosmic rays spectrum at (1 - 3) EeV and a steadily heavier composition with energy increasing. In order to explain this feature we assume that…
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…
Combining the results of targeted observations, H.E.S.S. has accumulated a large amount of extra-galactic exposure at TeV energies. Due to its large field of view a considerable part of the sky (0.6 sr) has been observed with high…
We report the results of 3D simulations of the trajectories of ultra-high energy protons and Fe nuclei (with energies $E = 4 \times 10^{19}$ and $2.5 \times 10^{20} eV$) propagating through the galactic magnetic field from the sources to…
Identification of the cosmic-ray (CR) `PeVatrons', which are sources capable of accelerating particles to $\sim10^{15}$ eV energies and higher, may lead to resolving the long-standing question of the origin of the spectral feature in the…
The all-sky surveys in gamma-rays by the imaging Compton telescope (COMPTEL) and the Energetic Gamma Ray Experiment Telescope (EGRET) on board the Compton Gamma Ray Observatory for the first time allows detailed studies of the extragalactic…
A thermal relic WIMP remains a prime candidate for the nature of Dark Matter, particularly for the more poorly constrained case of a heavy ($\gtrsim$ 1 TeV) WIMP. The highest fluxes from WIMP annihilations are expected in the region of the…
Extended $\gamma$-ray emission has been observed around several nearby pulsars and is commonly interpreted as inverse-Compton radiation produced by relativistic electrons and positrons diffusing in the surrounding interstellar medium. In…
Evidences of non-thermal X-ray emission and TeV gamma-rays from the supernova remnants (SNRs) has strengthened the hypothesis that primary Galactic cosmic-ray electrons are accelerated in SNRs. High energy electrons lose energy via…
It has been long discussed that cosmic rays may contain signals of dark matter. In the last couple of years an anomaly of cosmic-ray positrons has drawn a lot of attentions, and recently an excess in cosmic-ray anti-proton has been reported…
Evidence for nonthermal activity in clusters of galaxies is well established from radio observations of synchrotron emission by relativistic electrons, and new windows (in EUV and Hard X-ray ranges) have provided more powerful tools for its…
Recently, the Large High Altitude Air Shower Observatory (LHAASO) reported the discovery of 12 ultrahigh-energy (UHE; $\mathrm{\varepsilon} \ge 100$ TeV) gamma-ray sources located in the Galactic plane. A few of these UHE gamma-ray emitting…
Detecting neutrinos and photons is crucial to identifying the sources of ultrahigh-energy cosmic rays (UHECRs), especially for transient sources. We focus on ultrahigh-energy gamma-ray emission from transient sources such as gamma-ray…