Merger-inspired rotation laws and the low-T/W instability in neutron stars
Merger-inspired rotation laws and the low-T/W instability in neutron stars
复制标题
合并激发的旋转定律和中子星的低 T/W 不稳定性
DOI：
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
N. Andersson
中科院分区：
文献类型：
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作者：
A. Passamonti;N. Andersson
受双中子星合并遗迹启发，我们实施了一系列微分旋转定律，考虑了旋转剖面对低 T/W 不稳定性的影响。我们利用牛顿引力中线性动力学方程的时间演化来研究非轴对称振荡并识别不稳定模式。低 T/W 不稳定性的存在和演化通过正则能量和角动量进行监测，同时从演化的动能中提取生长时间。新旋转定律的结果突出了与通常考虑的 j 常数定律的相似之处。当振荡模式与恒星共同旋转时（即，只要存在该模式的模式速度与整体角速度相匹配的点），并且在共同旋转区域深处增长得更快，就会出现不稳定性。然而，新的配置文件添加了一些功能，例如问题的附加同向旋转点，这会影响不稳定的发生。旋转定律对快速旋转模型中 l = m = 2 f 模式的振荡频率影响更大，但会影响任何旋转速率下的不稳定性增长时间。我们还确定了低 T/W 不稳定性似乎是由惯性模式触发的模型。我们讨论推断的定性行为在多大程度上可能具有观察相关性。
Implementing a family of differential rotation laws inspired by binary neutron-star merger remnants, we consider the impact of the rotation profile on the low-T/W instability. We use time evolutions of the linearised dynamical equations, in Newtonian gravity, to study non-axisymmetric oscillations and identify the unstable modes. The presence and evolution of the low-T/W instability is monitored with the canonical energy and angular momentum, while the growth time is extracted from the evolved kinetic energy. The results for the new rotation laws highlight similarities with the commonly considered j-constant law. The instability sets in when an oscillation mode co-rotates with the star (i.e. whenever there is a point where the mode’s pattern speed matches the bulk angular velocity) and grows faster deep inside the co-rotation region. However, the new profiles add features, like an additional co-rotation point to the problem, which affect the onset of instability. The rotation laws influence more drastically the oscillation frequencies of the l = m = 2 f-mode in fast rotating models, but affect the instability growth time at any rotation rate. We also identify models where the low-T/W instability appears to be triggered by inertial modes. We discuss to what extent the inferred qualitative behaviour is likely to be of observational relevance.
影响因子：
8.6
作者：
Abbott, B. P.;Abbott, R.;Zweizig, J.
通讯作者：
Zweizig, J.