标题： 孤立黑洞双星自旋进动和章动的特征 显示英文标题

标题： Signatures of spin precession and nutation in isolated black-hole binaries

摘要： 孤立大质量双星起源的双黑洞(BBH)自旋进动由潮汐、风、吸积、共同包层演化、新生反冲以及恒星核幔耦合等多种现象的相互作用决定。 在之前的研究中，我们确定了参数空间中的某些区域，这些区域可能产生因新生反冲而具有大角度偏差和通过三种机制（潮汐、吸积或最小核幔耦合继承）获得高自旋大小的BBH。 在这里，我们利用描述轨道角动量围绕总角动量的进动和章动幅度及频率的五个参数来探索此类BBH的自旋进动，并调节引力波辐射。只要至少有一个黑洞自旋足够强，新生反冲通常能够导致进动的发生。 章动是自旋-自旋耦合的结果，依赖于三种自旋增强机制。潮汐同步可以留下与对齐的有效自旋和章动频率之间的明显相关性，但不会产生大的章动。 当一个黑洞吸积其伴星包层的$\gtrsim 20\%$时，进动频率和幅度较大。 相比之下，当吸积者是沃尔夫-拉耶特（WR）星时，只需要更少量的吸积，例如$\approx 2\%$，即可提供较大的进动频率和幅度。 通过最小核幔耦合继承高新生WR自旋（最大破碎值的$\gtrsim 5\%$）是最有可能产生章动BBH的机制，这意味着从引力波观测中测量到的章动可能表明孤立双星起源且具有最小核幔耦合。 显示英文摘要

摘要： The spin precession of binary black holes (BBHs) that originate from isolated high-mass binary stars is determined by the interplay of phenomena such as tides, winds, accretion, common-envelope evolution, natal kicks, and stellar core-envelope coupling. In previous work, we identified regions of the parameter space that may produce BBHs with large misalignments from natal kicks and high spin magnitudes from three mechanisms - tides, accretion, or inheritance via minimal core-envelope coupling. Here, we explore the spin precession of such BBHs using five parameters that describe the amplitude and frequency with which the orbital angular momentum precesses and nutates about the total angular momentum, modulating the gravitational-wave emission. Precession is generally possible for sufficiently strong natal kicks provided at least one of the black holes is spinning. Nutation is a consequence of spin-spin coupling and depends on the three spin-up mechanisms. Tidal synchronization can leave a distinct correlation between the aligned effective spin and the nutation frequency, but does not produce large nutations. When a black hole accretes $\gtrsim 20\%$ of its companion's envelope, the precession frequency and amplitude are large. A much smaller amount of accretion, e.g., $\approx 2\%$, is needed to provide a large precession frequency and amplitude when the accretor is a Wolf-Rayet (WR) star. The inheritance of high natal WR spins ($\gtrsim 5\%$ of their maximum breakup value) via minimal core-envelope coupling is the most promising mechanism for producing nutating BBHs, implying that a measurement of nutation from gravitational-wave observations may suggest isolated-binary origin with minimal core-envelope coupling.