GRB afterglow light curves from uniform and non-uniform jets

CORC > 紫金山天文台 > 中国科学院紫金山天文台 > 宇宙伽马暴、中子星及相关物理研究团组

	GRB afterglow light curves from uniform and non-uniform jets
	Wei, DM; Jin, ZP
刊名	ASTRONOMY & ASTROPHYSICS
	2003-03-01
卷号	400 期号:2 页码:415-419
关键词	gamma rays : bursts ISM : jets and outflows
英文摘要	It is widely believed that gamma-ray bursts are produced by a jet-like outflows directed towards the observer, and the jet opening angle (theta(j)) is often inferred from the time at which there is a break in the afterglow light curves. Here we calculate the GRB afterglow light curves from a relativistic jet as seen by observers at a wide range of viewing angles (theta(v)) from the jet axis, and the jet is uniform or non-uniform (the energy per unit solid angle decreases smoothly away from the axis epsilon(theta) proportional to (theta/theta(c))(-k)). We find that, for uniform jet (k = 0), the afterglow light curves for different viewing angles are somewhat different: in general, there are two breaks in the light curve, the first one corresponds to the time at which gamma similar to (theta(j) - theta(v))(-1), and the second one corresponds to the time when gamma similar to (theta(j) + theta(v))(-1). However, for non-uniform jet, the things become more complicated. For the case theta(v) = 0, we can obtain the analytical results, for k < 8/(p+4) (where p is the spectral index of electron energy distribution) there should be two breaks in the light curve correspond to γ &SIM; θ(-1)(c) and gamma similar to theta(j)(-1) respectively, while for k > 8/(p + 4) there should be only one break corresponds to gamma similar to theta(c)(-1), and this provides a possible explanation for some rapidly fading afterglows whose light curves have no breaks since the time at which gamma similar to theta(c)(-1) is much earlier than our first observation time. For the case theta(v) not equal 0, our numerical results show that, the afterglow light curves are strongly affected by the values of theta(v), theta(c) and k. If theta(v) is close to theta(c) and k is small, then the light curve is similar to the case of k = 0, except the flux is somewhat lower. However, if the values of theta(v)/theta(c) and k are larger, there will be a prominent flattening in the afterglow light curve, which is quite different from the uniform jet, and after the flattening a very sharp break will be occurred at the time gamma similar to (theta(v) + theta(c))(-1).
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 BURST ; OPTICAL AFTERGLOW ; FIREBALL MODEL
收录类别	SCI
语种	英语
WOS记录号	WOS:000181298700003
内容类型	期刊论文
源URL	[http://libir.pmo.ac.cn/handle/332002/15824]
专题	紫金山天文台_宇宙伽马暴、中子星及相关物理研究团组
作者单位	1.Chinese Acad Sci, Purple Mt Observ, Nanjing, Peoples R China 2.Chinese Acad Sci, Natl Astron Observ, Beijing 100864, Peoples R China
推荐引用方式 GB/T 7714	Wei, DM,Jin, ZP. GRB afterglow light curves from uniform and non-uniform jets[J]. ASTRONOMY & ASTROPHYSICS,2003,400(2):415-419.
APA	Wei, DM,&Jin, ZP.(2003).GRB afterglow light curves from uniform and non-uniform jets.ASTRONOMY & ASTROPHYSICS,400(2),415-419.
MLA	Wei, DM,et al."GRB afterglow light curves from uniform and non-uniform jets".ASTRONOMY & ASTROPHYSICS 400.2(2003):415-419.