GRB radiative efficiencies derived from the swift data: GRBs versus XRFs, long versus short

	GRB radiative efficiencies derived from the swift data: GRBs versus XRFs, long versus short
	Zhang, B1 ; Liang, EW1,2 ; Page, KL 3; Grupe, D 4; Zhang BB(张彬彬)1,5 ; Barthelmy, SD 6; Burrows, DN 4; Campana, S 6; Chincarini, G 7,8; Gehrels, N 6
刊名	ASTROPHYSICAL JOURNAL
	2007-02-01
卷号	655 期号:2 页码:989-1001
关键词	gamma rays : bursts methods : statistical radiation mechanisms : nonthermal shock waves
ISSN号	0004-637X
通讯作者	Zhang, B (reprint author), Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA.
产权排序	第五完成单位
英文摘要	We systematically analyze the prompt emission and the early afterglow data of a sample of 31 GRBs detected by Swift before 2005 September and estimate the GRB radiative efficiency. BAT's narrow band inhibits a precise determination of the GRB spectral parameters, and we have developed a method to estimate these parameters with the hardness ratio information. The shallow decay component commonly existing in early X-ray afterglows, if interpreted as continuous energy injection in the external shock, suggests that the GRB efficiencies previously derived from the late-time X-ray data were not reliable. We calculate two radiative efficiencies using the afterglow kinetic energy E(K) derived at the putative deceleration time (t(dec)) and at the break time (t(b)), when the energy injection phase ends, respectively. At tb XRFs appear to be less efficient than normal GRBs. However, when we analyze the data at tdec, XRFs are found to be as efficient as GRBs. Short GRBs have similar radiative efficiencies to long GRBs despite of their different progenitors. Twenty-two bursts in the sample are identified to have the afterglow cooling frequency below the X-ray band. Assuming epsilon(e) 0:1, we find eta(gamma)(t(b)) usually < 10% and eta(gamma)(t(dec)) varying from a few percent to > 90%. Nine GRBs in the sample have the afterglow cooling frequency above the X-ray band for a very long time. This suggests a very small epsilon(B) and/or a very low ambient density n.
学科主题	Astronomy & Astrophysics
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	GAMMA-RAY-BURSTS ; AFTERGLOW LIGHT CURVES ; CONTINUOUS ENERGY INJECTION ; INTERNAL-SHOCK MODEL ; PHYSICAL PARAMETERS ; MILLISECOND PULSARS ; 2-COMPONENT JET ; ALERT TELESCOPE ; FIREBALL MODEL ; KINETIC-ENERGY
收录类别	SCI
原文出处	http://iopscience.iop.org/0004-637X/655/2/989/
语种	英语
WOS记录号	WOS:000243726000027
公开日期	2016-05-03
内容类型	期刊论文
源URL	[http://ir.ynao.ac.cn/handle/114a53/7027]
专题	云南天文台_星系研究组
作者单位	1.Department of Physics, University of Nevada, Las Vegas, NV 2.Department of Physics, Guangxi University, Nanning, China 3.Department of Physics and Astronomy, University of Leicester, Leicester, UK 4.Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 5.National Astronomical Observatory/Yunnan Observatory, Chinese Academy of Sciences, Kunming, China 6.NASA/Goddard Space Flight Center, Greenbelt, MD 7.INAF-Osservatorio Astronomico di Brera, Merate, Italy 8.Dipartmento di Fisica, Univeritá degli studi Milano-Bicocca, Milan, Italy 9.Astrophysics Research Institute, Liverpool John Moores University, Birkenhead, UK 10.Department of Physics, Pennsylvania State University, University Park, PA
推荐引用方式 GB/T 7714	Zhang, B,Liang, EW,Page, KL,et al. GRB radiative efficiencies derived from the swift data: GRBs versus XRFs, long versus short[J]. ASTROPHYSICAL JOURNAL,2007,655(2):989-1001.
APA	Zhang, B.,Liang, EW.,Page, KL.,Grupe, D.,Zhang BB.,...&Willingale, R.(2007).GRB radiative efficiencies derived from the swift data: GRBs versus XRFs, long versus short.ASTROPHYSICAL JOURNAL,655(2),989-1001.
MLA	Zhang, B,et al."GRB radiative efficiencies derived from the swift data: GRBs versus XRFs, long versus short".ASTROPHYSICAL JOURNAL 655.2(2007):989-1001.