THE HYDRODYNAMICS OF GAMMA-RAY BURST REMNANTS
THE HYDRODYNAMICS OF GAMMA-RAY BURST REMNANTS
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DOI：
10.1088/0004-637x/716/2/1028
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发表时间：
2008-08
期刊：
影响因子：
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通讯作者：
E. Ramirez-Ruiz;A. MacFadyen
中科院分区：
文献类型：
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作者：
E. Ramirez-Ruiz;A. MacFadyen
本文报道的结果，旨在解决如何修改的环爆介质的字符和可能存在的伴随超新星（SN）的伽玛射线暴（GRB）遗迹的最初各向异性外观的数值研究。本文给出了在均匀和非均匀外部介质中传播的轻脉冲射流的轴对称流体动力学计算，结果表明，自非相对论相开始以来，它们的残余物的动力学不同于标准的自相似解。由于大质量的星星的祖先预计有他们的近在周围修改的祖先风，我们认为自由风和冲击风作为可能的外部介质的伽玛暴残留物的演变。这里提供了大量的确认的重要概念，伽玛射线暴残留的形态和可见性在很大程度上取决于他们的拱星环境。由于这个原因，它们的可探测性高度偏向于那些具有大质量星星祖先的恒星;尽管在这类模型中，由于伽马射线暴喷出物最终被伴随的SN扫走，因此束射成分可能很难识别。然而，如果它们在稀薄的星际介质中膨胀，局部宇宙中不对称伽玛射线暴残留物的数密度可能会大得多，正如一些短伽玛射线暴祖先模型所预期的那样。在这些源中，可观测的不对称残留物的后期尺寸可以延伸到一个很宽的、可能可分辨的角度，并且可能更容易直接约束。
This paper reports on the results of a numerical investigation designed to address how the initially anisotropic appearance of a gamma-ray burst (GRB) remnant is modified by the character of the circumburst medium and by the possible presence of an accompanying supernova (SN). Axisymmetric hydrodynamical calculations of light, impulsive jets propagating in both uniform and inhomogeneous external media are presented, which show that the resulting dynamics of their remnants since the onset of the non-relativistic phase is different from the standard self-similar solutions. Because massive star progenitors are expected to have their close-in surroundings modified by the progenitor winds, we consider both free winds and shocked winds as possible external media for GRB remnant evolution. Abundant confirmation is provided here of the important notion that the morphology and visibility of GRB remnants are determined largely by their circumstellar environments. For this reason, their detectability is highly biased in favor of those with massive star progenitors; although, in this class of models, the beamed component may be difficult to identify because the GRB ejecta is eventually swept up by the accompanying SN. The number density of asymmetric GRB remnants in the local universe could be, however, far larger if they expand in a tenuous interstellar medium, as expected for some short GRB progenitor models. In these sources, the late size of the observable, asymmetric remnant could extend over a wide, possibly resolvable angle and may be easier to constrain directly.