The effect of spin mismodelling on gravitational-wave measurements of the binary neutron star mass distribution
The effect of spin mismodelling on gravitational-wave measurements of the binary neutron star mass distribution
复制标题
自旋错误模型对双中子星质量分布引力波测量的影响
DOI：
10.1093/mnras/stac347
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发表时间：
2022
影响因子：
4.8
通讯作者：
Sylvia Biscoveanu, Colm Talbot
中科院分区：
文献类型：
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作者：
Sylvia Biscoveanu, Colm Talbot
通过引力波观测测量的双中子星 (BNS) 质量分布有可能揭示有关致密物质状态方程、超新星物理、宇宙膨胀率和广义相对论测试的信息。由于当前大多数测量 BNS 质量分布的引力波分析并不同时拟合自旋分布，因此隐含的群体水平自旋分布与分析单个源时先前应用的自旋分布相同。在这项工作中，我们证明，在隐含的 BNS 自旋分布和真实的 BNS 自旋分布之间引入不匹配可能会导致推断的质量分布出现偏差。这是由于质量比和自旋分量的测量与各个源的轨道角动量之间存在很强的相关性。我们发现，应用低自旋先验排除群体中某些源的真实自旋大小会导致在群体水平上显着高估最大中子星质量，并低估最小中子星质量，而只有六个 BNS 检测。不会导致推断质量分布偏差的最安全的自旋先验选择是允许高自旋幅度和与轨道角动量不对齐的倾斜。
The binary neutron star (BNS) mass distribution measured with gravitational-wave observations has the potential to reveal information about the dense matter equation of state, supernova physics, the expansion rate of the Universe, and tests of general relativity. As most current gravitational-wave analyses measuring the BNS mass distribution do not simultaneously fit the spin distribution, the implied population-level spin distribution is the same as the spin prior applied when analysing individual sources. In this work, we demonstrate that introducing a mismatch between the implied and true BNS spin distributions can lead to biases in the inferred mass distribution. This is due to the strong correlations between the measurements of the mass ratio and spin components aligned with the orbital angular momentum for individual sources. We find that applying a low-spin prior that excludes the true spin magnitudes of some sources in the population leads to significantly overestimating the maximum neutron star mass and underestimating the minimum neutron star mass at the population level with as few as six BNS detections. The safest choice of spin prior that does not lead to biases in the inferred mass distribution is one that allows for high spin magnitudes and tilts misaligned with the orbital angular momentum.