Constraining the Type of Central Engine of GRBs with Swift Data

doi:10.3847/1538-4365/aabaf3

	Constraining the Type of Central Engine of GRBs with Swift Data
	Li,Liang 1,2,3; Wu,Xue-Feng 1; Lei,Wei-Hua 4; Dai,Zi-Gao 5; Lian,En-Wei 6; Ryde,Felix 3
刊名	The Astrophysical Journal Supplement Series
	2018-05-17
卷号	236 期号:2
关键词	methods: statistical reference systems X-rays: ISM
ISSN号	0067-0049
DOI	10.3847/1538-4365/aabaf3
英文摘要	Abstract The central engine of gamma-ray bursts (GRBs) is poorly constrained. There exist two main candidates: a fast-rotating black hole and a rapidly spinning magnetar. Furthermore, X-ray plateaus are widely accepted to be the energy injection into the external shock. In this paper, we systematically analyze the Swift/XRT light curves of 101 GRBs having plateau phases and known redshifts (before 2017 May). Since a maximum energy budget (～2?×?1052 erg) exists for magnetars but not for black holes, this provides a good clue to identifying the type of GRB central engine. We calculate the isotropic kinetic energy EK,iso and the isotropic X-ray energy release EX,iso for individual GRBs. We identify three categories based on how likely a black hole harbors a central engine: “Gold” (9 out of 101; both EX,iso and EK,iso exceed the energy budget), “Silver” (69 out of 101; EX,iso less than the limit but EK,iso greater than the limit), and “Bronze” (23 out of 101; the energies are not above the limit). We then derive and test the black hole parameters with the Blandford–Znajek mechanism, and find that the observations of the black hole candidate (“Gold”?+?“Silver”) samples are consistent with the expectations of the black hole model. Furthermore, we also test the magnetar candidate (“Bronze”) sample with the magnetar model, and find that the magnetar surface magnetic field (Bp) and initial spin period (P0) fall into reasonable ranges. Our analysis indicates that if the magnetar wind is isotropic, a magnetar central engine is possible for 20% of the analyzed GRBs. For most GRBs, a black hole is most likely operating.
语种	英语
出版者	The American Astronomical Society
WOS记录号	IOP:0067-0049-236-2-AABAF3
内容类型	期刊论文
源URL	[http://libir.pmo.ac.cn/handle/332002/21985]
专题	中国科学院紫金山天文台
作者单位	1.Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China; liang.li@fysik.su.se, xfwu@pmo.ac.cn 2.Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden 3.Department of Physics, KTH Royal Institute of Technology, SE-106 91 Stockholm, Sweden 4.School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China; leiwh@hust.edu.cn 5.School of Astronomy and Space Science, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China; dzg@nju.edu.cn 6.GXU-NAOC Center for Astrophysics and Space Sciences, Department of Physics, Guanxi University, Nanning 530004, People's Republic of China
推荐引用方式 GB/T 7714	Li,Liang,Wu,Xue-Feng,Lei,Wei-Hua,et al. Constraining the Type of Central Engine of GRBs with Swift Data[J]. The Astrophysical Journal Supplement Series,2018,236(2).
APA	Li,Liang,Wu,Xue-Feng,Lei,Wei-Hua,Dai,Zi-Gao,Lian,En-Wei,&Ryde,Felix.(2018).Constraining the Type of Central Engine of GRBs with Swift Data.The Astrophysical Journal Supplement Series,236(2).
MLA	Li,Liang,et al."Constraining the Type of Central Engine of GRBs with Swift Data".The Astrophysical Journal Supplement Series 236.2(2018).