POLARIZATION EVOLUTION OF EARLY OPTICAL AFTERGLOWS OF GAMMA-RAY BURSTS

	POLARIZATION EVOLUTION OF EARLY OPTICAL AFTERGLOWS OF GAMMA-RAY BURSTS
	Lan, Mi-Xiang 1,2; Wu, Xue-Feng3,4 ; Dai, Zi-Gao 1,2
刊名	ASTROPHYSICAL JOURNAL
	2016-01-10
卷号	816 期号:2
关键词	gamma-ray burst: general magnetic fields polarization radiation mechanisms: non-thermal shock waves
英文摘要	The central engine and jet composition of gamma-ray bursts (GRBs) remain mysterious. Here we suggest that observations on the polarization evolution of early optical afterglows may shed light on these questions. We first study the dynamics of a reverse shock and a forward shock that are generated during the interaction of a relativistic jet and its ambient medium. The jet is likely magnetized with a globally large-scale magnetic field from the central engine. The existence of the reverse shock requires that the magnetization degree of the jet should not be high (sigma <= 1), so that the jet is mainly composed of baryons and leptons. We then calculate the light curves and polarization evolution of early optical afterglows. and find that when the polarization position angle changes by 90 degrees during the early afterglow, the polarization degree is zero for a toroidal magnetic field but is very likely to be nonzero for an aligned magnetic field. This result would be expected to provide a probe for the central engine of GRBs. because an aligned field configuration could originate from a magnetar central engine and a toroidal field configuration could be produced from a black hole via the Blandford-Znajek mechanism. Finally, for such two kinds of magnetic field configurations, we fit the observed data of the early optical afterglow of GRB 120308A equally well.
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	MAGNETIC-FIELDS ; BLACK-HOLES ; LINEAR-POLARIZATION ; MILLISECOND PULSARS ; FLUID-DYNAMICS ; CENTRAL ENGINE ; NEUTRON-STARS ; BLAST WAVES ; EMISSION ; FIREBALLS
收录类别	SCI
语种	英语
WOS记录号	WOS:000368238500025
内容类型	期刊论文
源URL	[http://libir.pmo.ac.cn/handle/332002/16112]
专题	紫金山天文台_南极天文中心
作者单位	1.Nanjing Univ, Sch Astron & Space Sci, Nanjing 210093, Jiangsu, Peoples R China 2.Nanjing Univ, Minist Educ, Key Lab Modern Astron & Astrophys, Nanjing 210093, Jiangsu, Peoples R China 3.Chinese Acad Sci, Purple Mt Observ, Nanjing 210008, Peoples R China 4.Chinese Acad Sci, Joint Ctr Particle Nucl Phys & Cosmol, Purple Mt Observ, Nanjing Univ, Nanjing 210008, Peoples R China
推荐引用方式 GB/T 7714	Lan, Mi-Xiang,Wu, Xue-Feng,Dai, Zi-Gao. POLARIZATION EVOLUTION OF EARLY OPTICAL AFTERGLOWS OF GAMMA-RAY BURSTS[J]. ASTROPHYSICAL JOURNAL,2016,816(2).
APA	Lan, Mi-Xiang,Wu, Xue-Feng,&Dai, Zi-Gao.(2016).POLARIZATION EVOLUTION OF EARLY OPTICAL AFTERGLOWS OF GAMMA-RAY BURSTS.ASTROPHYSICAL JOURNAL,816(2).
MLA	Lan, Mi-Xiang,et al."POLARIZATION EVOLUTION OF EARLY OPTICAL AFTERGLOWS OF GAMMA-RAY BURSTS".ASTROPHYSICAL JOURNAL 816.2(2016).