LINEAR POLARIZATION IN GAMMA-RAY BURSTS: THE CASE FOR AN ORDERED MAGNETIC FIELD

@article{Granot2003LINEARPI,
  title={LINEAR POLARIZATION IN GAMMA-RAY BURSTS: THE CASE FOR AN ORDERED MAGNETIC FIELD},
  author={Jonathan Granot and Arieh Konigl},
  journal={The Astrophysical Journal},
  year={2003},
  volume={594}
}
Linear polarization at the level of ~1%-3% has by now been measured in several gamma-ray burst afterglows. Whereas the degree of polarization, P, was found to vary in some sources, the position angle, θp, was roughly constant in all cases. Until now, the polarization has been commonly attributed to synchrotron radiation from a jet with a tangled magnetic field that is viewed somewhat off-axis. However, this model predicts either a peak in P or a 90° change in θp around the "jet break" time in… 

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References

SHOWING 1-10 OF 29 REFERENCES
Gamma-ray burst afterglow: Polarization and analytic light curves
Gamma-ray burst afterglow polarization is discussed. We find an observable, up to ~10%, polarization, if the magnetic field coherence length grows at about the speed of light after the field is
Linear Polarization and Proper Motion in the Afterglow of Beamed Gamma-Ray Bursts
We investigate the polarization and proper motion from a beamed gamma-ray burst's ejecta. We find that even if the magnetic field has well-defined orientation relative to the direction of motion of
Polarization light curves and position angle variation of beamed gamma-ray bursts
The recently detected linear polarization in the optical lightcurve of GRB 990510 renewed the interest on how polarization can be produced in gamma-ray burst fireballs. Here we present a model based
Off-Axis Afterglow Emission from Jetted Gamma-Ray Bursts
We calculate gamma-ray burst (GRB) afterglow light curves from a relativistic jet as seen by observers at various viewing angles, θobs, relative to the jet axis. We describe three increasingly more
Polarization of the prompt γ-ray emission from the γ-ray burst of 6 December 2002
Observations of the afterglows of γ-ray bursts (GRBs) have revealed that they lie at cosmological distances, and so correspond to the release of an enormous amount of energy. The nature of the
Steepening of Afterglow Decay for Jets Interacting with Stratified Media
We calculate light curves for gamma-ray burst afterglows when material ejected in the explosion is confined to a jet that propagates in a medium with a power-law density profile. The observed
The Shape of Spectral Breaks in Gamma-Ray Burst Afterglows
Gamma-ray burst afterglows are well described by synchrotron emission from relativistic blast waves expanding into an external medium. The blast wave is believed to amplify the magnetic field and
Microlensing of Gamma-Ray Burst Afterglows
The afterglow of a cosmological gamma-ray burst (GRB) should appear on the sky as a narrow emission ring of radius ~3 × 1016 cm (t/day)5/8 that expands faster than light. After a day, the ring radius
GRB 990712: First Indication of Polarization Variability in a Gamma-Ray Burst Afterglow
TLDR
It is found that none of the existing models predict such polarization variations at a constant polarization angle; ways in which these models might be modified to accommodate the observed behavior of this afterglow are suggested.
Generation of Magnetic Fields in the Relativistic Shock of Gamma-Ray Burst Sources
We show that the relativistic two-stream instability can naturally generate strong magnetic fields with 10-5-10-1 of the equipartition energy density, in the collisionless shocks of gamma-ray burst
...
1
2
3
...