1. Detailed polarization measurements of the prompt emission of five Gamma-Ray Bursts
- Author
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Xin Liu, Shaolin Xiong, X. Y. Wen, Zheng-Heng Li, M. Pohl, Merlin Kole, Bobing Wu, N. Gauvin, A. Zwolinska, S. Orsi, Yuan-Hao Wang, Ruijie Wang, Shuang-Nan Zhang, Tianwei Bao, Radoslaw Marcinkowski, T. Bernasconi, Wojtek Hajdas, T. Tymieniecka, Franck Cadoux, Xiaofeng Zhang, Jiangtao Liu, T. Batsch, Nicolas Produit, Li-Ming Song, Xue-Feng Wu, Dominik Rybka, Laiyu Zhang, Xin Wu, Hualin Xiao, Junying Chai, Mi-Xiang Lan, Yongwei Dong, Jacek Szabelski, Jianchao Sun, Haoli Shi, Yongjie Zhang, Li Zhang, Zi-Gao Dai, Lu Li, and Han-Cheng Li
- Subjects
Physics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Brewster's angle ,010504 meteorology & atmospheric sciences ,Spectrometer ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astronomy and Astrophysics ,Polarimeter ,Astrophysics ,ddc:500.2 ,Polarization (waves) ,01 natural sciences ,symbols.namesake ,Astrophysical jet ,0103 physical sciences ,symbols ,Polar ,Gamma-ray burst ,Astrophysics - High Energy Astrophysical Phenomena ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences - Abstract
Gamma-ray bursts are the strongest explosions in the Universe since the Big Bang, believed to be produced either in forming black holes at the end of massive star evolution or merging of compact objects. Spectral and timing properties of gamma-ray bursts suggest that the observed bright gamma-rays are produced in the most relativistic jets in the Universe; however, the physical properties, especially the structure and magnetic topologies in the jets are still not well known, despite several decades of studies. It is widely believed that precise measurements of the polarization properties of gamma-ray bursts should provide crucial information on the highly relativistic jets. As a result there have been many reports of gamma-ray burst polarization measurements with diverse results, see, however many such measurements suffered from substantial uncertainties, mostly systematic. After the first successful measurements by the GAP and COSI instruments, here we report a statistically meaningful sample of precise polarization measurements, obtained with the dedicated gamma-ray burst polarimeter, POLAR onboard China's Tiangong-2 spacelab. Our results suggest that the gamma-ray emission is at most polarized at a level lower than some popular models have predicted; although our results also show intrapulse evolution of the polarization angle. This indicates that the low polarization degrees could be due to an evolving polarization angle during a gamma-ray burst., 34 pages, 15 figures (16 pages and 3 figures without supplementary information). Accepted for publication in Nature Astronomy, http://dx.doi.org/10.1038/s41550-018-0664-0
- Published
- 2019