Gravitational Radiation from Standing Accretion Shock Instability in Core-Collapse Supernovae
Gravitational Radiation from Standing Accretion Shock Instability in Core-Collapse Supernovae
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DOI：
10.1086/509320
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发表时间：
2006-07
期刊：
影响因子：
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通讯作者：
K. Kotake;N. Ohnishi;S. Yamada
中科院分区：
文献类型：
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作者：
K. Kotake;N. Ohnishi;S. Yamada
我们提出了数值实验的结果，其中我们研究了由常压吸积激波不稳定性（SASI）的增长引起的非球状性如何在核心坍缩超新星的反弹后阶段产生重力波形。为了获得中微子驱动的爆炸，我们参数化了从中心原中子星发射的中微子通量，并用一个灯泡方案近似中微子转移。我们发现，各向异性中微子发射的波形随时间单调增加，其振幅比原中子星外对流物质运动的波形大2个数量级。我们指出，当SASI的生长进入非线性阶段时，振幅开始变大，此时激波的变形和中微子各向异性变大。从波形的频谱分析中，我们发现中微子的振幅在~100 Hz以下的物质运动中占主导地位，这应该在下一代探测器（如LCGT和先进的LIGO）对10 kpc超新星的探测极限之内。作为对引力波背景的贡献，我们表明，这个来源的振幅在频率高于~ 1hz时可能比原始引力波背景更大，但不幸的是，对于拟议的天基探测器来说是不可见的。
We present the results of numerical experiments in which we study how asphericities induced by the growth of the standing accretion shock instability (SASI) produce gravitational waveforms in the postbounce phase of core-collapse supernovae. To obtain the neutrino-driven explosions, we parameterize the neutrino fluxes emitted from the central proto-neutron star and approximate the neutrino transfer by a light-bulb scheme. We find that the waveforms due to anisotropic neutrino emissions show a monotonic increase with time, whose amplitudes are up to 2 orders of magnitude larger than those from convective matter motions outside proto-neutron stars. We point out that the amplitudes begin to become larger when the growth of the SASI enters the nonlinear phase, in which the deformation of the shocks and the neutrino anisotropy become large. From the spectrum analysis of the waveforms, we find that the amplitudes from the neutrinos are dominant over those from the matter motions at frequencies below ~100 Hz, which should be within the detection limits of next-generation detectors such as LCGT and the advanced LIGO for a supernova at 10 kpc. As a contribution to the gravitational wave background, we show that the amplitudes from this source could be larger at frequencies above ~1 Hz than the primordial gravitational wave backgrounds but, unfortunately, invisible to the proposed space-based detectors.