| Afterglow Light Curves of Jetted Gamma-ray Burst Ejecta in Stellar Winds |
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| 作者姓名： | Xue-Feng Wu Zi-Gao Dai Yong-Feng Huang and Hai-Tao Ma |
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| 作者单位： | Xue-Feng Wu，Zi-Gao Dai，Yong-Feng Huang and Hai-Tao Ma Department of Astronomy，Nanjing University，Nanjing 210093; |
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| 基金项目： | Supported by the National Natural Science Foundation of China. |
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| 摘 要： | Optical and radio afterglows arising from shocks by relativistic conical ejecta running into pre-burst massive stellar winds are revisited. Under the homogeneous thin-shell approximation and a realistic treatment for the lateral expansion of jets, our results show that a notable break exists in the optical light curve in most cases we calculated in which the physical parameters are varied within reasonable ranges. For a relatively tenuous wind which cannot decelerate the relativistic jet to cause a light curve break within days, the wind termination shock due to the ram pressure of the surrounding medium occurs at a small radius, namely, a few times 1017 cm. In such a structured wind environment, the jet will pass through the wind within several hours and run into the outer uniform dense medium. The resulting optical light curve flattens with a shallower drop after the jet encounters the uniform medium, and then declines deeply, triggered by runaway lateral expansion.
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| 关 键 词： | 日照 曲线图 伽马射线 光学 相对论 |
Afterglow Light Curves of Jetted Gamma-ray Burst Ejecta in Stellar Winds |
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| Xue-Feng Wu,Zi-Gao Dai,Yong-Feng Huang and Hai-Tao Ma.Afterglow Light Curves of Jetted Gamma-ray Burst Ejecta in Stellar Winds[J].Chinese Journal of Astronomy and Astrophysics,2004,4(5):455-472. |
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| Authors: | Xue-FengWu Zi-GaoDai Yong-FengHuang Hai-TaoMa |
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| Institution: | DepartmentofAstronomy,NanjingUniversity,Nanjing210093 |
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| Abstract: | Optical and radio afterglows arising from shocks by relativistic conical ejecta running into pre-burst massive stellar winds are revisited. Under the homogeneous thin-shell approximation and a realistic treatment for the lateral expansion of jets, our results show that a notable break exists in the optical light curve in most cases we calculated in which the physical parameters are varied within reasonable ranges. For a relatively tenuous wind which cannot decelerate the relativistic jet to cause a light curve break within days, the wind termination shock due to the ram pressure of the surrounding medium occurs at a small radius, namely, a few times 10^17 cm. In such a structured wind environment, the jet will pass through the wind within several hours and run into the outer uniform dense medium. The resulting optical light curve flattens with a shallower drop after the jet encounters the uniform medium, and then declines deeply, triggered by runaway lateral expansion. |
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| Keywords: | hydrodynamics - relativity - shock waves - gamma-rays: bursts |
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