0 Photon acceleration in variable ultra - relativistic outflows and high - energy spectra of Gamma - Ray
نویسندگان
چکیده
MeV seed photons produced in shocks in a variable ultra-relativistic outflow gain energy by the Fermi mechanism, because the photons Compton scatter off relativistically colliding shells. The Fermi-modified high-energy photon spectrum has a non-universal slope and a universal cutoff. A significant increase in the total radiative efficiency is possible. In some gamma ray bursts, most of the power might be emitted at the high-energy cutoff for this mechanism, which would be close to 100 MeV for outflows with a mean bulk Lorentz factor of 100.
منابع مشابه
Cosmic ray acceleration in subluminal and superluminal relativistic shock environments
The flux of Ultra High Energy Cosmic Rays (UHECRs) at E > 1018.5 eV is believed to arise in plasma shock environments in extragalactic sources. Galactic sources are not able to generate these high energies and the distribution of charged particles is too isotropic to originate from the galaxy. The best candidates for particle acceleration up to 1021 eV are believed to be the Active Galactic Nuc...
متن کاملUltra-high energy cosmic rays, cascade γ-rays, and high-energy neutrinos from gamma-ray bursts
Gamma-ray bursts (GRBs) are sources of energetic, highly variable fluxes of γ rays, which demonstrates that they are powerful particle accelerators. Besides relativistic electrons, GRBs should also accelerate high-energy hadrons, some of which could escape cooling to produce ultra-high energy cosmic rays (UHECRs). Acceleration of high-energy hadrons in GRB blast waves will be established if hig...
متن کامل2 00 8 On the origin of ultra high energy cosmic rays : Subluminal and superluminal relativistic shocks
The flux of ultra high energy cosmic rays (UHECRs) at E > 1018.5 eV is believed to arise in plasma shock environments in extragalactic sources. In this paper, we present a systematic study of particle acceleration by relativistic shocks, in particular concerning the dependence on bulk Lorentz factor and the angle between the magnetic field and the shock flow. For the first time, simulation resu...
متن کامل2 00 8 On the origin of ultra high energy cosmic rays :
The flux of ultra high energy cosmic rays (UHECRs) at E > 1018.5 eV is believed to arise in plasma shock environments in extragalactic sources. In this paper, we present a systematic study of particle acceleration by relativistic shocks, in particular concerning the dependence on bulk Lorentz factor and the angle between the magnetic field and the shock flow. For the first time, simulation resu...
متن کاملSelf-consistent Radiative Effects on Particle Acceleration via Relativistic Electromagnetic Outflows
Plasma outflows from gamma-ray bursts (GRB), pulsar winds, and relativistic jets radiate high energy emission. However, the radiation damping effect is ignored in conventional simulations. In this letter, we study the radiation damping effect on particle acceleration via Poynting fluxes in two-andhalf-dimensional particle-in-cell (PIC) plasma simulation with magnetized electron-positron plasmas...
متن کامل