| Tail Emission from a Ring-like Jet: Its Application to Shallow Decays of Early Afterglows and GRB 050709 |
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| 作者姓名： | Yuan-Chuan Zou and Zi-Gao Dai |
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| 作者单位： | Yuan-Chuan Zou and Zi-Gao Dai 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： | Similar to the case of pulsars the magnetic axis and the spin axis of gamma-ray burst sources may not lie on the same line. This may cause the formation of a ring-like jet due to collimation of the processing magnetic axis. We analyze the tail emission from such a jet, and find that it has a shallow decay phase with a temporal index of -1/2 if the Lorentz factor of the ejecta is not very high, which is consistent with the shallow decay phase of some early X-ray afterglow detected by Swift. The ring-like jet has a tail cusp with sharp rising and very sharp decay. This effect can provide an explanation for the re-brightening and sharp decay of the X-ray afterglow of GRB 050709.
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Tail Emission from a Ring-like Jet: Its Application to Shallow Decays of Early Afterglows and GRB 050709 |
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| Yuan-Chuan Zou and Zi-Gao Dai.Tail Emission from a Ring-like Jet: Its Application to Shallow Decays of Early Afterglows and GRB 050709[J].Chinese Journal of Astronomy and Astrophysics,2006,6(5). |
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| Authors: | Yuan-Chuan Zou Zi-Gao Dai |
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| Abstract: | Similar to the case of pulsars the magnetic axis and the spin axis of gamma-ray burst sources may not lie on the same line. This may cause the formation of a ring-like jet due to collimation of the processing magnetic axis. We analyze the tail emission from such a jet, and find that it has a shallow decay phase with a temporal index of -1/2 if the Lorentz factor of the ejecta is not very high, which is consistent with the shallow decay phase of some early X-ray afterglow detected by Swift. The ring-like jet has a tail cusp with sharp rising and very sharp decay. This effect can provide an explanation for the re-brightening and sharp decay of the X-ray afterglow of GRB 050709. |
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| Keywords: | gamma rays: bursts - X-rays: general |
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