标题： 伽马射线暴是时间不对称的 显示英文标题

标题： Gamma-Ray Bursts are Time-Asymmetric

摘要： 一种检测时间不对称性的简单测试被设计并应用于由 aboard the {\it 康普顿}伽马射线天文台上的暴发和瞬态源实验（BATSE）探测到的最亮伽马射线暴。我们展示了证据，表明单个暴发在所有测试的时间尺度上都是时间不对称的，从短于构成伽马射线暴脉冲的时间尺度到与包含这些脉冲的大致持续时间相似的时间尺度。我们也发现了只在接近暴发持续时间的时间尺度上表现出显著不对称性的暴发，以及在任何时间尺度上都没有明显不对称性的暴发。不对称性的特征是暴发和/或组成部分结构的上升时间比衰减时间更短。我们还发现，当我们把整个暴发样本放在一起时，它们整体上是时间不对称的，在所有测试的时间尺度和所有能量带中，有更多暴发和脉冲的上升比衰减更快。当我们将整个伽马射线暴样本以64毫秒的间隔分组，并在整个BATSE能量范围内积分时，统计显著性达到了6 $\sigma$水平。因此，预测时间对称性的模型被排除了。 显示英文摘要

摘要： A simple test for time-asymmetry is devised and carried out on the brightest gamma-ray bursts detected by the Burst and Transient Source Experiment (BATSE) on board the {\it Compton} Gamma Ray Observatory. We show evidence that individual bursts are time-asymmetric on all time scales tested, from a time scale shorter than that of pulses which compose GRBs to a time scale similar to a greater envelope that contains these pulses. We also find bursts which manifest significant asymmetry only on time scales comparable to the duration of burst, and bursts for which no clear asymmetry on any time scale is present. The sense of the asymmetry is that bursts and/or component structures rise in a shorter time than they decay. We also find that our whole sample of bursts taken together is time- asymmetric, in that there are significantly more bursts and pulses where the rise is more rapid than the decay, on all time scales tested and for all energy bands tested. When our whole GRB sample is binned at 64-ms and integrated over all BATSE energies, the statistical significance is at the 6 $\sigma$ level. Models that predict time-symmetry are therefore excluded.