paper

Multi-Wave band Synchrotron Polarization of Gamma-Ray Burst Afterglows

arXiv:2005.03710 · doi:10.3847/1538-4357/abf2c2

Abstract

Multi-wave band synchrotron linear polarization of gamma-ray burst (GRB) afterglows is studied under the assumption of an anisotropic turbulent magnetic field with a coherence length of the plasma skin-depth scale in the downstream of forward shocks. We find that for typical GRBs, in comparison to the optical polarization, the degree of radio polarization shows a similar temporal evolution but a significantly smaller peak value. This results from differences in observed intensity image shapes between the radio and optical bands. We also show that the degree of the polarization spectrum undergoes a gradual variation from the low- to the high-polarization regime above the intensity of the spectral peak frequency, and that the difference in polarization angles in the two regimes is zero or 90 degrees. Thus, simultaneous multi-wave band polarimetric observations of GRB afterglows would be a new determinative test of the plasma-scale magnetic field model. We also discuss theoretical implications from the recent detection of radio linear polarization in GRB 171205A with ALMA and other models of magnetic field configuration.

arXiv comment16 pages, 12 figures, revised version of 2, accepted by ApJ in publication

References in corpus (69)

Cited by in corpus (11)