Related papers: Peak energy clustering and efficiency in compact o…
We study the spectrum of high frequency radiation emerging from mildly dissipative photospheres of long-duration gamma-ray burst outflows. Building on the results of recent numerical investigations, we assume that electrons are heated…
The gamma-ray space telescopes AGILE and Fermi detected short and bright synchrotron gamma-ray flares at photon energies above 100 MeV in the Crab Nebula. This discovery suggests that electron-positron pairs in the nebula are accelerated to…
We extend de concept of Compton scattering to the case of plasmons. This concept was originally applied to electrons in vacuum. Here, we consider electrons in a plasma, and study the scattering properties of photon-plasmon interactions. We…
We compile 23 Gamma-ray Bursts (GRBs) and 21 blazars with estimated Doppler factors, and the Doppler factors of GRBs are estimated from their Lorentz factors by assuming their jet viewing angles \theta->0 degree. Using the conventional…
Synchrotron radiation mechanism, when electrons are accelerated in a relativistic shock, is known to have serious problems to explain the observed gamma-ray spectrum below the peak for most Gamma-Ray Bursts (GRBs); the synchrotron spectrum…
Particles with energies below the mean energy $E_0$ in relativistic shocked plasmas should assume an equilibrium energy distribution. This leads to a synchrotron spectrum $F_\nu \propto \nu^{1/3}$ up to approximately the critical frequency…
We explore the physics of electron acceleration in a plasma medium in an effective field theory framework. Employing a multiple Compton scattering mechanism, it is found that the acceleration can be sustained in such a medium so as to…
Calibration of the absolute energy scale at high-energy photon (gamma-gamma, gamma-electron) colliders is discussed. The luminosity spectrum at photon colliders is broad and has a rather sharp high-energy edge, which can be used, for…
In the advent of next generation gamma-ray missions, we present general properties of spectral features of high-energy emission above $1\MeV$ expected for a class of millisecond, low magnetic field ($\sim 10^9\G$) pulsars. We extend…
We consider the emission of photons from the inner parts of a relativistically expanding plasma outflow, characterized by a constant Lorentz factor, Gamma. Photons that are injected in regions of high optical depth are advected with the…
Polarization characteristics of the gamma beam obtained by the Compton back scattering of laser photons on high energy electrons are evaluated by Monte-Carlo simulations. It is assumed that outgoing photons are tagged; the energy dispersion…
In a dense gas plasma a short laser pulse propagates in relativistic self-trapping mode, which enables effective conversion of laser energy to the accelerated electrons. This regime sustains effective loading which maximizes the total…
Quasi-thermal Comptonization in internal shocks formed between relativistic shells can account for the high energy emission of gamma-ray bursts. This is in fact the dominant cooling mechanism if the typical energy of the emitting particles…
The highly luminous and variable prompt emission in Gamma-Ray Bursts (GRBs) arises in an ultra-relativistic outflow. The exact underlying radiative mechanism shaping its non-thermal spectrum is still uncertain, making it hard to determine…
The generation of energetic electron bunches by the interaction of a short, ultra-intense ($I>10^{19} \textrm{W/cm}^2$) laser pulse with "grating" targets has been investigated in a regime of ultra-high pulse-to-prepulse contrast…
The limit on the intrinsic brightness temperature, attributed to `Compton catastrophe', has been established being $10^{12}$~K. Somewhat lower limit of the order of $10^{11.5}$~K is implied if we assume that the radiating plasma is in…
Models for the evolution of the integrated energy spectrum of primary cosmic ray electrons in clusters of galaxies have been calculated, including the effects of losses due to inverse Compton (IC), synchrotron, and bremsstrahlung emission,…
We perform time-resolved spectroscopy on the prompt emission in gamma-ray bursts (GRBs) and identify a thermal, photospheric component peaking at a temperature of a few hundreds keV. This peak does not necessarily coincide with the broad…
In the recent Letter [1] we considered the approach of nonequilibrium pair plasma towards thermal equilibrium state adopting a kinetic treatment and solving numerically the relativistic Boltzmann equations. It was shown that plasma in the…
Knowledge of the bulk Lorentz factor $\Gamma_{0}$ of GRBs allows us to compute their comoving frame properties shedding light on their physics. Upon collisions with the circumburst matter, the fireball of a GRB starts to decelerate,…