DELAYED ENERGY INJECTION MODEL FOR GAMMA-RAY BURST AFTERGLOWS
DELAYED ENERGY INJECTION MODEL FOR GAMMA-RAY BURST AFTERGLOWS
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DOI：
10.1088/0004-637x/779/1/28
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发表时间：
2013-07
期刊：
影响因子：
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通讯作者：
J. Geng;X. Wu;Y. F. Huang;Y. Yu
中科院分区：
文献类型：
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作者：
J. Geng;X. Wu;Y. F. Huang;Y. Yu
伽玛射线暴（GRBs）余辉中的浅衰减阶段和耀斑被广泛认为与中心引擎的后期激活有关。一些能量注入模型涉及自GRB触发时间以来的连续能量流，例如来自磁星的磁偶极子辐射。然而，在涉及黑洞吸积系统的情况下，来自回退吸积的能量流可能会延迟一个回退时间~ tfb。因此，我们提出了一个延迟能量注入模型。延迟的能量会导致外部激波的洛伦兹系数显著上升，这将在多波段余辉中“产生”一个凸起。如果延迟时间很短，我们的模型退化到之前的模型。我们的模型可以解释GRB 081029和GRB 100621A的光学和红外光曲线中明显的再亮。需要相当大的后撤质量来提供后期的能量；这表明伽马射线暴伴随回退物质可能与低能超新星有关，因此包层的部分可以在爆发期间存活下来。回溯时间可以提供有关GRB祖星性质的有意义的信息。
The shallow decay phase and flares in the afterglows of gamma-ray bursts (GRBs) are widely believed to be associated with the later activation of the central engine. Some models of energy injection involve a continuous energy flow since the GRB trigger time, such as the magnetic dipole radiation from a magnetar. However, in the scenario involving a black hole accretion system, the energy flow from the fall-back accretion may be delayed for a fall-back time ∼tfb. Thus, we propose a delayed energy injection model. The delayed energy would cause a notable rise to the Lorentz factor of the external shock, which will “generate” a bump in the multiple band afterglows. If the delayed time is very short, our model degenerates to the previous models. Our model can explain the significant re-brightening in the optical and infrared light curves of GRB 081029 and GRB 100621A. A considerable fall-back mass is needed to provide the later energy; this indicates that GRBs accompanied with fall-back material may be associated with a low energy supernova so that the fraction of the envelope can survive during eruption. The fall-back time can give meaningful information on the properties of GRB progenitor stars.