Afterglow Lightcurves, Viewing Angle and the Jet Structure of Gamma‐Ray Bursts
Afterglow Lightcurves, Viewing Angle and the Jet Structure of Gamma‐Ray Bursts
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DOI：
10.1063/1.1579370
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发表时间：
2003-05
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影响因子：
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通讯作者：
E. Rossi;D. Lazzati;M. Rees
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作者：
E. Rossi;D. Lazzati;M. Rees
伽马射线暴通常被建模为指向观测者的喷流；射流的锥角通常是从余辉的幂律衰减中出现陡增的时间推断出来的。我们考虑了另一种模型，其中射流具有光束模式，其中单位立体角（可能还有初始洛伦兹因子）的亮度从轴方向平滑地减小，而不是具有明确定义的锥角，其中流动是均匀的。我们显示，在余辉光曲线的中断，然后发生在一个时间，这取决于视角。从不同的角度来看，余辉断裂的数据可能与标准的射流一致，而不是暗示本质上不同的射流范围——一些非常窄，而另一些具有相似的功率，分布在一个更宽的锥上。讨论了该模型对光度函数的意义，并与实测数据进行了比较。我们还讨论了一些预测。
Gamma ray bursts are often modelled as jet‐like outflows directed towards the observer; the cone angle of the jet is then commonly inferred from the time at which there is a steepening in the power‐law decay of the afterglow. We consider an alternative model in which the jet has a beam pattern where the luminosity per unit solid angle (and perhaps also the initial Lorentz factor) decreases smoothly away from the axis, rather than having a well‐defined cone angle within which the flow is uniform. We show that the break in the afterglow light curve then occurs at a time that depends on the viewing angle. Instead of implying a range of intrinsically different jets — some very narrow, and others with similar power spread over a wider cone — the data on afterglow breaks could be consistent with a standardized jet, viewed from different angles. We discuss the implication of this model for the luminosity function and compare with data. We also discuss some predictions.