arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0909.3622astro-ph.HEastro-ph.CO
收藏

用各向异性中微子辐射的射线追踪分析估算核塌缩超新星中的引力波

Ray-Tracing Analysis of Anisotropic Neutrino Radiation for Estimating Gravitational Waves in Core-Collapse Supernovae

Kei Kotake, Wakana Iwakami, Naofumi Ohnishi, Shoichi Yamada

摘要:

提出了一种射线追踪方法来估计超新星核中各向异性中微子发射产生的引力波。为了计算引力波形,我们推导出一个有用的形式,这也适用于三维计算的解析公式。推动核心崩溃之前的缓慢旋转的证据,我们专注于中微子发射和质子中子星外的物质运动的非球面性。基于模拟SASI辅助的中微子加热爆炸的二维模型,采用后处理的射线追踪方法计算了中微子各向异性,并计算了相应的波形。通过这些计算,发现与先前通过逐射线分析估计的波形相比,波形表现出更多的变化(例如,Kotake等人(2007))。除了一个积极的增长功能,这是预测确定的总波振幅占主导地位,波形显示出大的负增长的SASI的增长过程中的一些时代。发现这些特征源于横向方向上的中微子发射过量,这可以通过射线追踪计算精确地捕获。由于射线追踪方法适当地考虑了中微子的负贡献和中微子的散射,使得波的振幅比以前的估计小了一个数量级以上,从而使它们很难被探测到星系源。另一方面,指出物质运动产生的GW谱在$\sim 100$ Hz附近有一个峰值,这可能是SASI引发的超新星爆炸的特征。(节略)

英文摘要:

We propose a ray-tracing method to estimate gravitational waves (GWs) generated by anisotropic neutrino emission in supernova cores. To calculate the gravitational waveforms, we derive analytic formulae in a useful form, which are applicable also for three-dimensional computations. Pushed by evidence of slow rotation prior to core-collapse, we focus on asphericities in neutrino emission and matter motions outside the protoneutron star. Based on the two-dimensional (2D) models, which mimic SASI-aided neutrino heating explosions, we compute the neutrino anisotropies via the ray-tracing method in a post-processing manner and calculate the resulting waveforms. With these computations, it is found that the waveforms exhibit more variety in contrast to the ones previously estimated by the ray-by-ray analysis (e.g., Kotake et al. (2007)). In addition to a positively growing feature, which was predicted to determine the total wave amplitudes predominantly, the waveforms are shown to exhibit large negative growth for some epochs during the growth of SASI. These features are found to stem from the excess of neutrino emission in lateral directions, which can be precisely captured by the ray-tracing calculation. Due to the negative contributions and the neutrino absorptions appropriately taken into account by the ray-tracing method, the wave amplitudes become more than one-order-of magnitude smaller than the previous estimation, thus making their detections very hard for a galactic source.On the other hand, it is pointed out that the GW spectrum from matter motions have its peak near $\sim 100$ Hz, which could be characteristic for the SASI-induced supernova explosions.(abridged)

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑