Relativistic Wind Bubbles and Afterglow Signatures
Relativistic Wind Bubbles and Afterglow Signatures
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DOI：
10.1086/383019
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发表时间：
2003-08
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影响因子：
--
通讯作者：
Z. Dai
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文献类型：
--
作者：
Z. Dai
高磁化、快速旋转的致密天体被广泛认为是γ射线暴（GRB）的中心能量源。在伽玛暴之后，这样的类磁星物体可能通过一些磁驱动过程直接失去其旋转能量，这产生可能由电子-正电子对的能流主导的超相对论风。这样的风与向外膨胀的火球相互作用导致了相对论风泡，它被认为是研究得很好的蟹状星云的相对论版本。我们在这里探索这个风泡的动力学及其排放特征。我们发现，当注入能量大大超过火球的初始能量时，风泡的体积洛伦兹因子衰减比以前更慢，更重要的是，反向激波发射可以主导余辉发射，这会产生余辉光变曲线的颠簸。此外，高极化的凸块发射将是预期的，如果在冲击风的环形磁场占主导地位的随机分量。
Highly magnetized, rapidly rotating compact objects are widely argued to be central energy sources of γ-ray bursts (GRBs). After the GRB, such a magnetar-like object may directly lose its rotational energy through some magnetically driven processes, which produce an ultrarelativistic wind dominated possibly by the energy flux of electron-positron pairs. The interaction of such a wind with an outward-expanding fireball leads to a relativistic wind bubble, which is regarded as a relativistic version of the well-studied Crab Nebula. We here explore the dynamics of this wind bubble and its emission signatures. We find that when the injection energy significantly exceeds the initial energy of the fireball, the bulk Lorentz factor of the wind bubble decays more slowly than before, and more importantly, the reverse-shock emission could dominate the afterglow emission, which yields a bump in afterglow light curves. In addition, high polarization of the bump emission would be expected if a toroidal magnetic field in the shocked wind dominates over the random component.