Related papers: Observational Limits on Inverse Compton Processes …
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 paper explores the transition between Compton Scattering and Inverse Compton Scattering (ICS), which is characterized by an equal exchange of energy and momentum between the colliding particles (electrons and photons). This regime has…
Relativistically expanding sources of X-rays and gamma-rays cover an enormous range of (central) compactness and Lorentz factor. The underlying physics is discussed, with an emphasis on how the dominant dissipative mode and the emergent…
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 emission processes responsible for the observed X-rays from radio jets are commonly believed to be non-thermal, but in any particular case, it is unclear if synchrotron emission or one or more varieties of inverse Compton emission…
We investigate the spatial and spectral properties of non-thermal emission from clusters of galaxies at gamma-ray energies between 10 keV and 10 TeV due to inverse-Compton (IC) emission, pion-decay and non-thermal bremsstrahlung (NTB) from…
We discuss some open problems concerning the origin and the emission mechanism of gamma-ray bursts (GRBs) in light of recent developments. If GRBs originate at extragalactic distances, we are facing four crises: (1) an energy crisis, models…
It is proposed that the spectra of so called 'MeV blazars' can be explained in terms of previously developed models of the external comptonization of accretion disk radiation provided that the structure of the inner and outer parts of the…
We study synchrotron self-inverse Compton radiation from a reverse-shocked fireball. If the inverse Compton process dominates the cooling of shocked electrons, an X-ray flare produced by the first order Compton scattering would emerge in…
The observational diversity of ``gamma-ray bursts'' (GRBs) has been increasing, and the natural inclination is a proliferation of models. We explore the possibility that at least part of this diversity is a consequence of a single basic…
We discuss here constraints on the particle acceleration models from the observed gamma-ray bursts spectra. The standard synchrotron shock model assumes that some fraction of available energy is given instantaneously to the electrons which…
A new theory for gamma-ray burst radiation is presented. In this theory, magnetic fields and relativistic electrons are created through plasma processes arising as a relativistic shell passes through the interstellar medium. The gamma-rays…
The prompt GRB emission is thought to arise from electrons accelerated in internal shocks propagating within a highly relativistic outflow. The launch of Fermi offers the prospect of observations with unprecedented sensitivity in…
The feasibility of generation of bright ultrashort gamma-ray pulses is demonstrated in the interaction of a relativistic electron bunch with a counterpropagating tightly-focused superstrong laser beam in the radiation dominated regime. The…
We investigate two high energy radiation mechanisms, the proton synchrotron and the electron inverse Compton emission, and explore their possible signatures in the broad-band spectra and in the keV to GeV light curves of gamma-ray burst…
We study the prompt phase of low-luminosity Gamma-Ray Bursts (ll-GRBs) as potential source of very-high-energy (VHE) gamma rays and Ultra-High-Energy Cosmic Rays (UHECRs). Within the internal shock model we choose parameters for the…
Gamma-ray bursts (GRBs) are believed to originate from ultra-relativistic winds/fireballs to avoid the "compactness problem". However, the most energetic photons in GRBs may still suffer from $\gamma-\gamma$ absorption leading to…
Galactic diffuse continuum gamma-ray emission is intricately related to cosmic-ray physics and radio astronomy. We describe recent results from an approach which endeavours to take advantage of this. Information from cosmic-ray composition…
Supercriticality of the same kind as that in a nuclear pile can take place in high-energy astrophysical objects producing a number of impressive effects. For example, it could cause an explosive release of the energy of a cloud of…
Internal shocks are a leading candidate for the dissipation mechanism that powers the prompt $\gamma$-ray emission in gamma-ray bursts (GRBs). In this scenario a compact central source produces an ultra-relativistic outflow with varying…