Photon acceleration in variable ultra-relativistic outflows and high-energy spectra of Gamma-Ray Bursts

Abstract

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.

8 pages, submitted to ApJL

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Cited by in corpus (8)

• Prompt high-energy emission from gamma-ray bursts in the internal shock model
• Synchrotron Radiation as the Source of Gamma-Ray Burst Spectra
• A Photosphere-Internal Shock Model of Gamma-Ray Bursts: Case Studies of Fermi/LAT Bursts
• Nonthermal gamma-ray and X-ray flashes from shock breakout in gamma-ray bursts/supernovae
• Re-born fireballs in Gamma-Ray Bursts
• Cocoon shock breakout emission from binary neutron star mergers
• Bulk Compton Emission in the GRB Internal Shock Model
• Compton driven beam formation and magnetisation via plasma microinstabilities