Gamma-ray polarization induced by cold electrons via Compton processes

Abstract

The polarization measurement is an important tool to probe the prompt emission mechanism in gamma-ray bursts (GRBs). The synchrotron photons can be scattered by cold electrons in the outflow via Compton scattering processes. The observed polarization depends on both the photon energy and the viewing angle. With the typical bulk Lorentz factor $\Gamma \sim 200$, photons with energy $E>10$ MeV tend to have smaller polarization than photons with energy $E<1$ MeV. At the right viewing angle, i.e. $\theta \sim {\Gamma }^{-1}$, the polarization achieves its maximal value, and the polarization angle changes $90^{\circ }$ relative to the initial polarization direction. Thus, the synchrotron radiation plus Compton scattering model can naturally explain the $90^{\circ }$ change of the polarization angle in GRB 100826A.

19 Pages, 5 figures, 1 table

References in corpus (11)

• The Internal-Collision-Induced Magnetic Reconnection and Turbulence (ICMART) Model of Gamma-Ray Bursts
• Klein-Nishina Effects on Optically Thin Synchrotron and Synchrotron Self-Compton Spectrum
• GRB110721A: An extreme peak energy and signatures of the photosphere
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• Evolution of the polarization of the optical afterglow of the gamma-ray burst GRB 030329
• The extremely high peak energy of GRB 110721A in the context of a dissipative photosphere synchrotron emission model
• Interpretation and implication of the non-detection of GeV spectrum excess by Fermi gamma-ray Space Telescope in most GRBs
• Inverse Compton cooling in Klein-Nishina regime and GRB prompt spectrum
• Anomalies in low-energy Gamma-Ray Burst spectra with the Fermi Gamma-Ray Burst Monitor

Cited by in corpus (9)

• Polarimetry of cosmic gamma-ray sources above e+e- pair creation threshold
• Probing Magnetic Fields of GRB X-ray Flares with Polarization Observations
• Gamma-ray burst polarization via Compton scattering process
• Polarization of photons scattered by electrons in any spectral distribution
• The change of GRB polarization angles in the magnetic-dominated jet model
• Gamma-ray polarization of synchrotron-self-Compton process from a highly relativistic jet
• Time-averaging Polarimetric and Spectral Properties of Gamma-Ray Bursts
• Polarization of gamma-ray burst afterglows in the synchrotron self-Compton process from a highly relativistic jet
• Detectability of Polarized Gamma-ray Emission from Blazar Flares with COSI