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arXiv 0901.1133astro-ph.HE
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相对论Turbulence模型中的GRB光变曲线

GRB Light Curves in the Relativistic Turbulence Model

Ayah Lazar, Ehud Nakar, Tsvi Piran

摘要:

在相对论膨胀壳层中随机取向的相对论发射体提供了一种替代内部冲击的机制,用于产生具有有效的能量到辐射的可变光变曲线。在这个模型中,相对论外流被分解成在外流静止坐标系中相对论运动的小发射体。可变性的出现是因为观察者只在发射体的速度指向他时才能看到它,因此只有一小部分发射体被给定的观察者看到。具有显著相对论性随机运动的模型需要将总能量的大部分转换并保持为这些运动。虽然目前还不清楚这是如何实现的,我们在这里探索,使用两个玩具模型,所需的参数,以产生光变曲线的观测相媲美的约束。我们发现,一个紧密的发射器的大小和散装和随机洛伦兹因子之间的关系是必要的,随机洛伦兹因子决定的变异性。虽然这两种模型都成功地产生了观察到的变异性,但与光变曲线的其他属性存在一些不一致之处。如果中央引擎长时间处于活动状态,产生许多壳层,在某种程度上类似于内部冲击模型,那么其中的大部分问题(但不是全部问题)可能会得到解决。

英文摘要:

Randomly oriented relativistic emitters in a relativistically expanding shell provides an alternative to internal shocks as a mechanism for producing GRBs' variable light curves with efficient conversion of energy to radiation. In this model the relativistic outflow is broken into small emitters moving relativistically in the outflow's rest frame. Variability arises because an observer sees an emitter only when its velocity points towards him so that only a small fraction of the emitters are seen by a given observer. Models with significant relativistic random motions require converting and maintaining a large fraction of the overall energy into these motions. While it is not clear how this is achieved, we explore here, using two toy models, the constraints on parameters required to produce light curves comparable to the observations. We find that a tight relation between the size of the emitters and the bulk and random Lorentz factors is needed and that the random Lorentz factor determines the variability. While both models successfully produce the observed variability there are several inconsistencies with other properties of the light curves. Most of which, but not all, might be resolved if the central engine is active for a long time producing a number of shells, resembling to some extent the internal shocks model.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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