| A Detailed Study on the Equal Arrival Time Surface Effect in Gamma-Ray Burst Afterglows |
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| 作者姓名： | Yong-Feng Huang Ye Lu Anna Yuen Lam Wong Kwong Sang Cheng |
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| 作者单位： | Department of Physics The University of Hong Kong Pokfulam Road Hong Kong，Department of Physics The University of Hong Kong Pokfulam Road Hong Kong |
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| 基金项目： | 国家自然科学基金;国家自然科学基金;全国高等学校优秀博士学位论文作者专项基金 |
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| 摘 要： | Due to the relativistic motion of gamma-ray burst remnant and its deceleration in the circumburst medium, the equal arrival time surfaces at any moment are not spherical, rather, they are distorted ellipsoids. This will leave some imprints in the afterglows. We study the effect of equal arrival time surfaces numerically for various circumstances, i.e., isotropic fireballs, collimated jets, density jumps and energy injection events. For each case, a direct comparison is made between including and not including the effect. For isotropic fireballs and jets viewed on axis, the effect slightly hardens the spectra and postpones the peak time of the afterglows, but does not change the shapes of the spectra and light curves significantly. In the cases of a density jump or an energy injection, the effect smears out the variations in the afterglows markedly.
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| 关 键 词： | gamma rays: bursts — relativity — shock waves — ISM: clouds |
| 修稿时间： | 2006-08-15 |
A Detailed Study on the Equal Arrival Time Surface Effect in Gamma-Ray Burst Afterglows |
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| Yong-Feng Huang Ye Lu Anna Yuen Lam Wong Kwong Sang Cheng.A Detailed Study on the Equal Arrival Time Surface Effect in Gamma-Ray Burst Afterglows[J].Chinese Journal of Astronomy and Astrophysics,2007,7(3):397-404. |
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| Authors: | Yong-Feng Huang Ye Lu Anna Yuen Lam Wong Kwong Sang Cheng |
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| Abstract: | Due to the relativistic motion of gamma-ray burst remnant and its deceleration in the circumburst medium, the equal arrival time surfaces at any moment are not spherical, rather, they are distorted ellipsoids. This will leave some imprints in the afterglows. We study the effect of equal arrival time surfaces numerically for various circumstances, i.e., isotropic fireballs, collimated jets, density jumps and energy injection events. For each case, a direct comparison is made between including and not including the effect. For isotropic fireballs and jets viewed on axis, the effect slightly hardens the spectra and postpones the peak time of the afterglows, but does not change the shapes of the spectra and light curves significantly. In the cases of a density jump or an energy injection, the effect smears out the variations in the afterglows markedly. |
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| Keywords: | gamma rays:bursts-relativity-shock waves-ISM:clouds |
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