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Title: Poynting flux dominated jets challenged by their photospheric emission

One of the key open question for gamma-ray bursts (GRBs) jets, is the magnetization of the outflow. Here we consider the photospheric emission of Poynting flux dominated outflows, when the dynamics is mediated by magnetic reconnection. We show that thermal three-particle processes, responsible for the thermalization of the plasma, become inefficient far below the photosphere. Conservation of the total photon number above this radius, combined with Compton scattering below the photosphere enforces kinetic equilibrium between electrons and photons. This, in turn, leads to an increase in the observed photon temperature, which reaches ≳ 8 MeV (observed energy) when decoupling the plasma at the photosphere. This result is weakly dependent on the free model parameters. The predicted peak energy is more than an order of magnitude higher than the observed peak energy of most GRBs, which puts strong constraints on the magnetization of these outflows.
Authors:
 [1] ;  [2]
  1. The Oskar Klein Centre for Cosmoparticle Physics, AlbaNova, SE-106 91 Stockholm (Sweden)
  2. (Sweden)
Publication Date:
OSTI Identifier:
22494332
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1693; Journal Issue: 1; Conference: 2. ICRANet Cesar Lattes meeting on supernovae, neutron stars and black holes, Rio de Janeiro (Brazil), 13-22 Apr 2015; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COMPTON EFFECT; COSMIC GAMMA BURSTS; DECOUPLING; ELECTRONS; EMISSION; EQUILIBRIUM; MAGNETIC RECONNECTION; MAGNETIZATION; MEV RANGE 01-10; PARTICLES; PEAKS; PHOTON TEMPERATURE; PHOTONS; PHOTOSPHERE; PLASMA; THERMALIZATION