Spectra and Time Variability

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Spectra and Time Variability
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• There are at least two outstanding issues with
  the standard GRB model
• Most of the RBW energy is stored in relativistic
  protons. These are necessary in order to
  transport the energy to the required distances,
  because they do not lose energy promptly. For the
  same reason it is hard to extract this energy
  when needed.
• Most of the luminosity is emitted at energy 0.1
  1.0 MeV this is strange because the prompt GRB
  emission is considered to be due to synchrotron
  by relativistic electrons assuming their LF same
  as shock Ep G4, much too strong to account for
  the observations.

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• We propose a model that can resolve both these
  issues simultaneously. The model relies
• 1. On an instability that relativistic proton
  plasmas with B-fields suffer due to the
  production of internally produced sychrotron
  radiation.
• 2. On the amplification of the instability by
  relativistic motion and reflection of the
  internally produced radiation by upstream located
  matter.

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Shock Mirror Geometry
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• We have modeled this process numerically. We
  assume the presence of scattering medium at R
  1016 cm and of finite radial extension.
• We then follow the evolution of the proton,
  electron and photon distribution by solving the
  corresponding kinetic equations.
• We then obtain the spectra as a function of time
  for the prompt GRB emission.
• The time scales are given in units of the
  comoving blob crossing time.

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• TEST

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• Epeak as a function of the magnetic field B

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Observed light curves depend on accretion rate m.
This may account for the observed lack of power
at high frequencies, i.e. the PSD simply reflects
the modulation of m (by an unknown upstream
mechanism).
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Then ....
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formation region, generally not much different
than the
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