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arXiv 1304.4372astro-ph.HE
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快速旋转超新星核中低模螺旋不稳定性的引力波特征

Gravitational Wave Signatures from Low-mode Spiral Instabilities in Rapidly Rotating Supernova Cores

Takami Kuroda, Tomoya Takiwaki, Kei Kotake

摘要:

采用广义相对论流体动力学方法,在近似中微子输运的条件下,研究了15 M_odot星旋转核坍缩产生的引力波的性质。通过参数化地改变坍缩前的角动量,我们专注于旋转的影响GW签名在早期postbounce演化。对于三味中微子输运,我们基于Thorne的动量形式,求解了辐射能量和动量的能量平均集。除了物质运动产生的引力四极辐射外,我们还考虑了各向异性中微子辐射产生的引力波。通过这些计算,我们的结果提出了几个支持的证据,为以前的预期,非轴对称不稳定性起着至关重要的作用,在确定后反弹GW签名。在瞬发对流,我们发现,波形显示窄带和高度准周期信号,持续到模拟结束。我们指出,这种特征反映了单臂螺旋模的增长。准周期波形的典型频率可以很好地解释为失速激波和旋转的原中子星表面之间的传播声波,这表明了驻定吸积激波不稳定性的出现。虽然GW信号在两种偏振和不同的观测方向之间表现出很强的变化性,但如果具有足够角动量的源位于我们的银河系中,它们就在下一代探测器(如KAGRA和Advanced LIGO)的探测范围内。

英文摘要:

We study properties of gravitational waves (GWs) from rotating core-collapse of a 15M_odot star by performing three-dimensional general-relativistic hydrodynamic simulations with an approximate neutrino transport. By parametrically changing the precollapse angular momentum, we focus on the effects of rotation on the GW signatures in the early postbounce evolution. Regarding three-flavor neutrino transport, we solve the energy-averaged set of radiation energy and momentum based on the Thorne's momentum formalism. In addition to the gravitational quadrupole radiation from matter motions, we take into account GWs from anisotropic neutrino emission. With these computations, our results present several supporting evidences for the previous anticipation that non-axisymmetric instabilities play an essential role in determining the postbounce GW signatures. During prompt convection, we find that the waveforms show narrow-band and highly quasi-periodic signals which persist until the end of simulations. We point out that such feature reflects the growth of the one-armed spiral modes. The typical frequency of the quasi-periodic waveforms can be well explained by the propagating acoustic waves between the stalled shock and the rotating proto-neutron star surface, which suggests the appearance of the standing-accretion-shock instability. Although the GW signals exhibit strong variability between the two polarizations and different observer directions, they are within the detection limits of next generation detectors such as by KAGRA and Advanced LIGO, if the source with sufficient angular momentum is located in our Galaxy.

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。

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