2025ApJS..280...39L

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 π_obs ∝ 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 π_obs ∝ 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 π_obs ∝ 1/S_obs, dominantly determined by how “magnetic patches” are randomly distributed in the observed emission region S_obs 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.