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arXiv 2304.04801gr-qcastro-ph.HE
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进动双黑洞系统的高效多时间尺度动力学

Efficient multi-timescale dynamics of precessing black-hole binaries

Davide Gerosa, Giulia Fumagalli, Matthew Mould, Giovanni Cavallotto, Diego Padilla Monroy, Daria Gangardt, Viola De Renzis

AI总结:

本文采用多时间尺度方法与加权自旋差参数化,推导二阶后牛顿双黑洞自旋进动的闭合动力学,并在 PRECESSION v2 中实现 50 倍加速。

摘要:

我们利用多时间尺度方法,展示了在二阶后牛顿阶数下双黑洞自旋进动的解析与数值进展。除了常用的、作为运动常数的有效自旋之外,我们还利用了加权自旋差,并证明这种重新参数化消除了先前公式在等质量双星情形下受到的坐标奇点影响。我们在共进动坐标系和惯性坐标系中,均以闭合形式写下了进动时间尺度上的动力学。随后可以准绝热方式引入辐射反作用,从而至少对于准圆轨道上的双星而言,引力波旋进可简化为求解单个常微分方程。我们对由此产生的现象学进行了广泛综述,并采用新采用的参数化方式重写了相关物理内容,包括自旋-轨道共振、上下不稳定性、过去时间无穷远处的自旋传播,以及将用于引力波天文学的新型进动估计量。我们的研究结果已在公开 Python 模块 PRECESSION 的第 2 版中实现。在单个现成处理器上,从/向任意大间距执行一次进动平均的后牛顿演化仅需不超过 0.1 秒——与我们先前的实现相比速度提升了 50 倍。这使得广泛的应用成为可能,包括传播引力波后验样本以及具有天体物理性质的种群合成预测。

英文摘要:

We present analytical and numerical progress on black-hole binary spin precession at second post-Newtonian order using multi-timescale methods. In addition to the commonly used effective spin which acts as a constant of motion, we exploit the weighted spin difference and show that such reparametrization cures the coordinate singularity that affected the previous formulation for the case of equal-mass binaries. The dynamics on the precession timescale is written down in closed form in both coprecessing and inertial frames. Radiation reaction can then be introduced in a quasi-adiabatic fashion such that, at least for binaries on quasi-circular orbits, gravitational inspirals reduce to solving a single ordinary differential equation. We provide a broad review of the resulting phenomenology and rewrite the relevant physics in terms of the newly adopted parametrization. This includes the spin-orbit resonances, the up-down instability, spin propagation at past time infinity, and new precession estimators to be used in gravitational-wave astronomy. Our findings are implemented in version 2 of the public Python module PRECESSION. Performing a precession-averaged post-Newtonian evolution from/to arbitrarily large separation takes $\lesssim 0.1$ s on a single off-the-shelf processor - a 50x speedup compared to our previous implementation. This allows for a wide variety of applications including propagating gravitational-wave posterior samples as well as population-synthesis predictions of astrophysical nature.

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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