The change of GRB polarization angles in the magnetic-dominated jet model

Abstract

The polarimetric measurement on the prompt phase of GRB 100826A shows that the polarization angle changes $\sim 90^{\circ }$ between two adjacent time intervals. We will show that this phenomenon can be naturally interpreted in the framework of the magnetic-dominated jet (MDJ) model. The MDJ model suggests that the bulk Lorentz factor of the outflow increases as $\Gamma \propto r^{1/3}$, until reaching a saturated value ${\Gamma }_{\mathrm{sat}}$. Electrons move in the globally ordered magnetic field advected by the jet from the central engine and produce synchrotron photons. The polarized synchrotron photons travel alone the jet direction and then collide with the cold electrons at the front of the jet. After the Compton scattering process, these photons escape from the jet and are detected by the observer locating slightly off-axis. If photons are emitted before the bulk Lorentz factor saturates, the change of polarization angle is a natural result of the acceleration of the outflow.

7 pages, 2 figures

References in corpus (5)

• The Internal-Collision-Induced Magnetic Reconnection and Turbulence (ICMART) Model of Gamma-Ray Bursts
• Ten per cent polarized optical emission from GRB 090102
• Polarisation studies of the prompt gamma-ray emission from GRB 041219a using the Spectrometer aboard INTEGRAL
• Evolution of the polarization of the optical afterglow of the gamma-ray burst GRB 030329
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Cited by in corpus (4)

• Gamma-ray burst polarization reduction induced by the Lorentz invariance violation
• The polarization-angle flip in GRB prompt emission
• Polarization of gamma-ray burst afterglows in the synchrotron self-Compton process from a highly relativistic jet
• INTEGRAL Results on Gamma-Ray Bursts and Polarization of Hard X-ray Sources