2025ApJS..280...39L -
Astrophys. J., Suppl. Ser., 280, 39 (2025/September-0)
Relativistic Effects and Gamma-Ray Burst Polarization in Power-law Evolution.
LI L., XUE S.-S. and CAI R.-G.
Abstract (from CDS):
Despite decades of polarization observations and high significance of polarized γ-ray, X-ray, optical, and radio emissions in gamma-ray bursts (GRBs) accumulating in dozens of cases, people have yet to find a consistent scenario for understanding the globally observed timing properties of GRB polarization to date. Here, we report that the observed properties of GRB polarization exhibit a four-segment timing evolution at a cosmological distance: (i) an initial hump early on (within the first few seconds); (ii) a later-on power-law decay (from ∼101 to ∼104 s), which takes the form of πobs ∝ t^-0.50 ± 0.02^; (iii) afterward a late-time rebrightening hump (from ∼104 to ∼105 s); and (iv) finally a flattening power-law decay (from ∼105 to ∼107 s), with the form of πobs ∝ t^-0.21 ± 0.08^. We show that these results can be explained by relativistic and geometric effects of a highly relativistic and magnetized jet generated by a central engine, and “magnetic patches” distributed as a globally random but locally coherent form. The long-term timing evolution of observed GRB polarization follows a scaling law πobs ∝ 1/Sobs, dominantly determined by how “magnetic patches” are randomly distributed in the observed emission region Sobs on the jet plane of 1/Γ cone. It predicts the polarization hump and tail form in accordance with the luminosity jet-break phenomenon. Our analysis suggests that there is a single dominant mechanism (relativistic and geometric effects) that may account for the global observational properties of GRB polarization, and other emission mechanisms and effects may play a role in spatially local and temporally short effects on GRB polarization.
Abstract Copyright:
© 2025. The Author(s). Published by the American Astronomical Society.
Journal keyword(s):
Gamma-ray bursts - Astronomy data analysis - Time domain astronomy
Status at CDS
:
Large table(s) will be appraised for possible ingestion in VizieR.
Simbad objects:
76
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