暗物质混合中子星的双流体$f$模振荡
Two-fluid $f$-mode oscillations of dark-matter-admixed neutron stars
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中文总结 AI 辅助
研究暗物质混合中子星的双流体$f$模振荡，在广义相对论中求解双流体微扰方程得复本征频率，频谱含两个主要$f$类序列，中等DM分数时双流体分支之一弱辐射，阻尼时间增加，还给出相关振幅和阻尼时间以估计GW能量，扩展了先前研究。
中文摘要 AI 辅助
我们在完全广义相对论（GR）中研究暗物质混合中子星（DANSs）的四极$f$模振荡。普通成分由与Shen2020地壳匹配的微观Brueckner - Hartree - Fock物质描述，而暗物质（DM）成分被视为仅通过引力与普通物质耦合的冷自相互作用费米子流体。对于固定DM分数序列，我们用外向引力波（GW）边界条件求解极向双流体微扰方程，得到复本征频率。频谱包含两个主要的$f$类序列，其局部特征可由普通物质主导、DM主导或混合，通过成分动能、位移重叠和物质四极矩的抵消来诊断。主要结果是，对于中等DM分数，双流体分支之一可变为弱辐射，阻尼时间增加几个数量级。同样的计算给出外向Zerilli振幅和GW阻尼时间，用于估计达到规定探测器阈值所需的GW能量。因此，该分析通过保留度规微扰和辐射边界条件扩展了先前的双流体考林研究。
英文摘要
We study quadrupolar $f$-mode oscillations of dark-matter-admixed neutron stars (DANSs) in full general relativity (GR). The ordinary component is described by microscopic Brueckner-Hartree-Fock matter matched to the Shen2020 crust, while the dark matter (DM) component is treated as a cold self-interacting fermion fluid coupled to ordinary matter only by gravity. For fixed-DM-fraction sequences we solve the polar two-fluid perturbation equations with an outgoing gravitational-wave (GW) boundary condition, obtaining complex eigenfrequencies rather than only real mode frequencies. The spectrum contains two principal $f$-like sequences. Their local character can be ordinary-matter-led, DM-led, or mixed, and is diagnosed using the component kinetic energies, the displacement overlap, and the cancellation of the matter quadrupole. A main result is that, for intermediate DM fractions, one of the two-fluid branches can become weakly radiating, with damping times enhanced by several orders of magnitude. The same calculation gives the outgoing Zerilli amplitude and the GW damping time, which we use to estimate the GW energy required to reach a prescribed detector threshold. Thus the analysis extends previous two-fluid Cowling studies by retaining metric perturbations and the radiative boundary condition.
