标题： 4U 1636-536 X射线暴发期间的反极热点证据 显示英文标题

标题： Evidence for Antipodal Hot Spots During X-ray Bursts From 4U 1636-536

摘要： 在几颗中子星低质量X射线双星的热核X射线暴中发现的高频亮度振荡，对千赫兹准周期亮度振荡的拍频模型、核燃烧传播、中子星表层磁场结构以及高密度物质状态方程具有重要意义。 这些意义关键取决于所观测到的频率是否是恒星自转频率或是其第一泛音。 这里我们报告了对来自4U 1636-536的五次爆发的分析，这些爆发在大约580 Hz处显示出强烈的振荡。 我们证明，结合这五次爆发前0.75秒的数据，可以得到一个在290 Hz处的信号，在考虑试验次数的情况下，该信号在$4\times 10^{-5}$水平上具有显著性。 这强烈表明290 Hz是这个中子星的自转频率，而580 Hz是它的第一泛音，这与关于此源的其他论点一致，但与文献中提出的580 Hz是真实自转频率的建议相反。 这里使用的这种方法，即一种算法，用于组合五次爆发的时间序列数据以使580 Hz振荡的相位对齐，可用于任何源中寻找频率与强振荡频率有确定关系的弱振荡。 显示英文摘要

摘要： The discovery of high-frequency brightness oscillations in thermonuclear X-ray bursts from several neutron-star low-mass X-ray binaries has important implications for the beat frequency model of kilohertz quasi-periodic brightness oscillations, the propagation of nuclear burning, the structure of the subsurface magnetic fields in neutron stars, and the equation of state of high-density matter. These implications depend crucially on whether the observed frequency is the stellar spin frequency or its first overtone. Here we report an analysis of five bursts from 4U 1636-536 which exhibit strong oscillations at approximately 580 Hz. We show that combining the data from the first 0.75 seconds of each of the five bursts yields a signal at 290 Hz that is significant at the $4\times 10^{-5}$ level when the number of trials is taken into account. This strongly indicates that 290 Hz is the spin frequency of this neutron star and that 580 Hz is its first overtone, in agreement with other arguments about this source but in contrast to suggestions in the literature that 580 Hz is the true spin frequency. The method used here, which is an algorithm for combining time series data from the five bursts so that the phases of the 580 Hz oscillations are aligned, may be used in any source to search for weak oscillations that have frequencies related in a definite way to the frequency of a strong oscillation.