Related papers: The proton low-mass microquasar: high-energy emiss…
The recent detection of TeV gamma-rays from the microquasar LS 5039 by HESS is one of the most exciting discoveries of observational gamma-ray astronomy in the very high energy regime. This result clearly demonstrates that X-ray binaries…
We investigate gamma-ray emission in the impulsive phase of solar flares and the detectability of non-thermal signatures from protostellar flares. Energetic solar flares emit high-energy gamma rays of GeV energies, but their production…
Black holes (BH), one of the most intriguing objects in the universe, can manifest themselves through electromagnetic radiation initiated by the accretion flow. Some stellar-mass BHs drive relativistic jets when accreting matter from their…
Blazars, the extreme family of AGN, can be strong gamma-ray emitters and constitute the largest fraction of identified point sources of EGRET. The next Gamma-ray Large Area Space Telescope (GLAST) is a high energy (30MeV-300GeV) gamma-ray…
High-energy gamma rays of interstellar origin are produced by the interaction of cosmic-ray (CR) particles with the diffuse gas and radiation fields in the Galaxy. The main features of this emission are well understood and are reproduced by…
Recently, two nearby prominent starburst galaxies, M82 and NGC253, have been detected as point-like sources with gamma-ray telescopes at TeV energies [1] [2]. It has been claimed that these detections show that the cosmic ray intensity in…
Blazars with redshifts z<0.1 are likely candidates for detection at energies in the range 300 GeV - 50 TeV with Cerenkov telescopes and scintillator arrays. We present gamma-ray flux predictions for a sample of 15 nearby flat-spectrum radio…
It is well established that phenomenological two-zone diffusion models of the galactic halo can very well reproduce cosmic-ray nuclear data and the observed antiproton flux. Here, we consider lepton propagation in such models and compute…
I review some of the basic observational details of jets from X-ray binaries, or `microquasars'. It is shown that in both (Z and Atoll) NS and BHC systems radio emission, and therefore jet formation, is correlated with the presence of hard…
Context. The microquasar 1E 1740.7-2942 is a source located in the direction of the Galactic Center. It has been detected at X-rays, soft gamma-rays, and in the radio band, showing an extended radio component in the form of a double-sided…
Active Galactic Nuclei (AGN) host powerful jets containing high-energy electrons and protons. The astrophysical environment where AGNs and their jets are found is characterized by large concentrations of both dark matter (DM) and…
Massive protostars have associated bipolar outflows that can produce strong shocks when they interact with the surrounding medium. At these shocks particles can be accelerated up to relativistic energies. Relativistic electrons and protons…
Recently, microquasar jets have aroused the interest of many researchers focusing on the astrophysical plasma outflows and various jet ejections. In this work, we concentrate on the investigation of electromagnetic radiation and particle…
Despite the uncovered association of a high-energy neutrino with the apparent flaring state of blazar TXS 0506+056 in 2017, the mechanisms leading to astrophysical particle acceleration and neutrino production are still uncertain. Recent…
The high kinetic energy outflowing in the jets of microquasars is delivered to the surrounding interstellar medium. This energy input can cause the formation of bow shocks and cocoons that may be detectable from radio to gamma-ray energies.…
Recent studies by LHAASO have shown the presence of high-luminosity PeVatrons in our Galaxy. We examine two notable sources, each consisting of two pulsars, detected by LHAASO. We study gamma and cosmic-ray emissions from the surroundings…
We present multi-band observations of an extremely dusty star-forming lensed galaxy (HERS1) at $z=2.553$. High-resolution maps of \textit{HST}/WFC3, SMA, and ALMA show a partial Einstein-ring with a radius of $\sim$3$^{\prime\prime}$. The…
(abridged) Gamma-ray pulsars constitute a class of high and very high-energy emitters for which the known population is steadily increasing thanks to the Fermi/Large Area Telescope. In this paper, their gamma-ray luminosity and spectral…
The population of high energy and very high energy gamma-ray sources, detected with EGRET and the new generation of ground-based Cherenkov telescopes, conforms a reduced but physically important sample. Most of these sources are…
Very High Energy (VHE) gamma-rays in pulsars, and their surrounding halos, are interpreted to originate from the leptonic channel, electromagnetic interactions through electron inverse Compton (IC) scattering. In the hadronic scenario,…