Gamma-Ray Burst Optical Afterglows with Two-component Jets: Polarization Evolution Revisited

doi:10.3847/1538-4357/aac26e

	Gamma-Ray Burst Optical Afterglows with Two-component Jets: Polarization Evolution Revisited
	Lan,Mi-Xiang 1,2; Wu,Xue-Feng 2,3; Dai,Zi-Gao 1,4
刊名	The Astrophysical Journal
	2018-06-11
卷号	860 期号:1
关键词	gamma-ray burst: general magnetic fields polarization radiation mechanisms: non-thermal shock waves
ISSN号	0004-637X
DOI	10.3847/1538-4357/aac26e
英文摘要	Abstract Gamma-ray bursts have been widely argued to originate from binary compact object mergers or core collapse of massive stars. Jets from these systems may have two components: an inner, narrow sub-jet and an outer, wider sub-jet. Such a jet subsequently interacts with its ambient gas, leading to a reverse shock (RS) and a forward shock. The magnetic field in the narrow sub-jet is very likely to be mixed by an ordered component and a random component during the afterglow phase. In this paper, we calculate light curves and polarization evolution of optical afterglows with this mixed magnetic field in the RS region of the narrow sub-jet in a two-component jet model. The resultant light curve has two peaks: an early peak arising from the narrow sub-jet and a late-time rebrightening due to the wider sub-jet. We find the polarization degree (PD) evolution under such a mixed magnetic field confined in the shock plane is very similar to that under the purely ordered magnetic field condition. The two-dimensional “mixed” magnetic fields confined in the shock plane are essentially the ordered magnetic fields only with different configurations. The position angle (PA) of the two-component jet can change gradually or abruptly by 90°. In particular, an abrupt 90° change of the PA occurs when the PD changes from its decline phase to the rise phase.
语种	英语
出版者	The American Astronomical Society
WOS记录号	IOP:0004-637X-860-1-AAC26E
内容类型	期刊论文
源URL	[http://libir.pmo.ac.cn/handle/332002/21958]
专题	中国科学院紫金山天文台
作者单位	1.School of Astronomy and Space Science, Nanjing University, Nanjing 210093, People's Republic of China; mxlan@pmo.ac.cn, dzg@nju.edu.cn 2.Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China; xfwu@pmo.ac.cn 3.School of Astronomy and Space Science, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China 4.Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, People's Republic of China
推荐引用方式 GB/T 7714	Lan,Mi-Xiang,Wu,Xue-Feng,Dai,Zi-Gao. Gamma-Ray Burst Optical Afterglows with Two-component Jets: Polarization Evolution Revisited[J]. The Astrophysical Journal,2018,860(1).
APA	Lan,Mi-Xiang,Wu,Xue-Feng,&Dai,Zi-Gao.(2018).Gamma-Ray Burst Optical Afterglows with Two-component Jets: Polarization Evolution Revisited.The Astrophysical Journal,860(1).
MLA	Lan,Mi-Xiang,et al."Gamma-Ray Burst Optical Afterglows with Two-component Jets: Polarization Evolution Revisited".The Astrophysical Journal 860.1(2018).