标题： 关于伽马射线暴角分布中固有各向异性的存在性 显示英文标题

标题： On the existence of the intrinsic anisotropies in the angular distributions of gamma-ray bursts

摘要： 本文主要关注截止到1998年底，当前BATSE伽马射线暴（GRB）目录收集的2281个伽马射线暴在角分布中的固有各向异性，并且其次研究了伽马射线暴三个子类（“短时”，“中间时”，“长时”）的固有各向异性。文中基于每个类别在赤道坐标系下的球谐函数进行了检验。 由于BATSE仪器的天空曝光函数不依赖于时角（$\alpha$），任何与$P_n^m(\sin \delta) \sin m \alpha$或$P_n^m(\sin \delta) \cos m\alpha$成比例的非零球谐函数（其中$m \neq 0$为赤纬，$\delta$为时角）都立即表明存在一个固有的非零项。 令人惊讶的是，“中间时”子类在$97\%$显著性水平上显示出由高非零$P_3^1(\sin \delta) \sin m \alpha$谐波引起的固有各向异性。 剩余两个子类以及完整的伽马射线暴样本仍保持各向同性。 显示英文摘要

摘要： This articles is concerned primarily with the intrinsic anisotropy in the angular distribution of 2281 gamma-ray bursts (GRBs) collected in Current BATSE Gamma-Ray Burst Catalog until the end of year 1998, and, second, with intrinsic anisotropies of three subclasses ("short", "intermediate", "long") of GRBs. Testing based on spherical harmonics of each class, in equatorial coordinates, is presented. Because the sky exposure function of BATSE instrument is not dependent on the right ascension $\alpha$, any non-zero spherical harmonic proportional either to $P_n^m(\sin \delta) \sin m \alpha$ or to $P_n^m(\sin \delta) \cos m\alpha$ with $m \neq 0$ ($\delta$ is the declination), immediately indicates an intrinsic non-zero term. It is a somewhat surprising result that the "intermediate" subclass shows an intrinsic anisotropy at the $97\%$ significance level caused by the high non-zero $P_3^1(\sin \delta) \sin m \alpha$ harmonic. The remaining two subclasses, and the full sample of GRBs, remain isotropic.