We consider the effects of rapid pair creation by an intense pulse of γ-rays propagating ahead of a relativistic shock. Sidescattered photons colliding with the main γ-ray beam amplify the density of scattering charges. The acceleration rate of the pair-loaded medium is calculated and its limiting bulk Lorentz factor related to the spectrum and compactness of the photon source. One obtains, as a result, a definite prediction for the relative inertia in baryons and pairs. The deceleration of a relativistic shock in the moving medium and the resulting synchrotron emissivity are compared with existing results for a static medium. The radiative efficiency is increased dramatically by pair loading. When the initial ambient density exceeds a critical value, the scattering depth traversed by the main γ-ray pulse rises above unity and the pulse is broadened. This sets an upper limit to the preburst mass-loss rate of ∼10-5 M⊙ per year and places significant constraints on γ-ray burst progenitors. An anisotropic γ-ray flux (on an angular scale Γ-1 or larger) drives a large velocity shear that greatly increases the energy in the seed magnetic field forward of the propagating shock.

Thompson, C., Madau, P. (2000). Relativistic winds from compact gamma-ray sources. II. Pair loading and radiative acceleration in gamma-ray bursts. THE ASTROPHYSICAL JOURNAL, 538(1), 105-114 [10.1086/309100].

Relativistic winds from compact gamma-ray sources. II. Pair loading and radiative acceleration in gamma-ray bursts

Madau, P
2000

Abstract

We consider the effects of rapid pair creation by an intense pulse of γ-rays propagating ahead of a relativistic shock. Sidescattered photons colliding with the main γ-ray beam amplify the density of scattering charges. The acceleration rate of the pair-loaded medium is calculated and its limiting bulk Lorentz factor related to the spectrum and compactness of the photon source. One obtains, as a result, a definite prediction for the relative inertia in baryons and pairs. The deceleration of a relativistic shock in the moving medium and the resulting synchrotron emissivity are compared with existing results for a static medium. The radiative efficiency is increased dramatically by pair loading. When the initial ambient density exceeds a critical value, the scattering depth traversed by the main γ-ray pulse rises above unity and the pulse is broadened. This sets an upper limit to the preburst mass-loss rate of ∼10-5 M⊙ per year and places significant constraints on γ-ray burst progenitors. An anisotropic γ-ray flux (on an angular scale Γ-1 or larger) drives a large velocity shear that greatly increases the energy in the seed magnetic field forward of the propagating shock.
Articolo in rivista - Articolo scientifico
Cosmology: theory; Gamma rays: bursts; Radiation mechanisms: nonthermal;
English
2000
538
1
105
114
none
Thompson, C., Madau, P. (2000). Relativistic winds from compact gamma-ray sources. II. Pair loading and radiative acceleration in gamma-ray bursts. THE ASTROPHYSICAL JOURNAL, 538(1), 105-114 [10.1086/309100].
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/453356
Citazioni
  • Scopus 74
  • ???jsp.display-item.citation.isi??? 88
Social impact