Related papers: High Energy gamma-rays From FR I Jets
The jets of powerful blazars propagate within regions relatively dense of radiation produced externally to the jet. This radiation is a key ingredient to understand the origin of the high energy emission of blazars, from the X-ray to the…
High energy ($> 250$ keV) emission has been detected persisting for several tens of seconds after the initial spike of magnetar giant flares. It has been conjectured that this emission might arise via inverse Compton scattering in a highly…
The radiation observed by blazars is believed to originate from the transformation of bulk kinetic energy of relativistic jets into random energy. A simple way to achieve this is to have an intermittent central power source, producing…
The jet of the quasar 3C273 is observed at different spectral bands. This jet has a knot structure. Jet radiation in radio and optical bands are connected with synchrotron mechanism, while the emission mechanism producing the X-rays is…
M87 is the first extragalactic source detected in the TeV range that is not a blazar. With the increasing performances of ground-based Cherenkov telescopes, we can now probe the variability in the gamma-ray flux at small timescales, thus…
We discuss the possibility of observing ultra high energy cosmic ray sources inhigh energy gamma rays. Protons propagating away from their accelerators produce secondary electrons during interactions with cosmic microwave background…
We show that inverse Compton scattering of cosmic-microwave-background and starlight photons by cosmic-ray electrons in the interstellar and intergalactic space explains well the spectrum and intensity of the diffuse gamma-ray background…
The radio galaxy Cen A has been detected all the way up to the TeV energy range. This raises the question about the dominant emission mechanisms in the high-energy domain. Spectral analysis allows us to put constraints on the possible…
We propose a model for gamma-ray emitting microblazars based on the Compton interaction of a relativistic electron-positron plasma, ejected in a jet feature, with the UV-photon field provided by a high-mass stellar companion. Taking into…
Most of the Universe's populations of low energy cosmic ray electrons in the energy range of 1-100 MeV still manage to elude from detection by our instruments, since their synchrotron emission is at too low frequencies. We investigate a…
Recent observations of Sgr A$^*$ by Fermi and HESS have detected steady gamma-ray emission in the GeV and TeV bands. We present a new model to explain the GeV gamma-ray emission by inverse Compton scattering by nonthermal electrons supplied…
The gamma-ray emission detected from several microquasars can be produced by relativistic electrons emitting through inverse Compton scattering. In particular, the GeV emission detected from Cygnus X-3, and its orbital phase dependence,…
This study focuses on high-redshift, z > 3, quasars where resolved X-ray jets remain underexplored in comparison to nearby sources. Building upon previous work, we identify and confirm extended kpc-scale jets emission in two quasars…
A nearby super-luminous burst GRB 130427A was simultaneously detected by six $\gamma$-ray space telescopes ({\it Swift}, Fermi-GBM/LAT, Konus-Wind, SPI-ACS/INTEGRAL, AGILE and RHESSI) and by three RAPTOR full-sky persistent monitors. The…
The injection of ultra-high energy cosmic rays in the intergalactic medium leads to the production of a GeV-TeV gamma-ray halo centered on the source location, through the production of a high electromagnetic component in the interactions…
We construct a systematic survey of extragalactic \gamma-ray sky at the energies above 100 GeV using the data of Fermi telescope. Such survey has not been previously done by the ground-based Cherenkov gamma-ray telescopes which have,…
The preliminary detection of the Galactic Center black hole Sgr A* in X-rays by the Chandra mission, as well as recent mm-VLBI measurements, impose strict constraints on this source. Using a relativistic jet model for Sgr A*, we calculate…
We discuss the fluxes of high energy neutrinos and gamma-rays expected from AGNs if hadrons can be effectively accelerated to ultra-high energies by their relativistic jets, as currently believed. Fluxes of multi-TeV neutrinos detectable by…
Population studies of unidentified EGRET sources suggest that there exist at least three different populations of galactic gamma-ray sources. One of these populations is formed by young objects distributed along the galactic plane with a…
We compile the radio-optical-X-ray spectral energy distributions (SEDs) of 65 knots and 29 hotspots in 41 active galactic nucleus jets to examine their high energy radiation mechanisms. Their SEDs can be fitted with the single-zone leptonic…