发表机构
University of Florida; Harvard Society of Fellows; Center for Astrophysics | Harvard & Smithsonian; Université de Genève; The Adler Planetarium; Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA)（佛罗里达大学; 哈佛学会; 天体物理中心（哈佛大学与史密森尼学会）; 日内瓦大学; 阿德勒天文馆; 天体物理学跨学科探索与研究中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究使用POSYDON代码模拟不同金属丰度下双中子星的形成，发现低金属丰度提高并合效率并产生更对称的质量比，为多信使时代解释宇宙学DNS种群提供框架。
AI 中文摘要
在通过引力波（GW）发射探测到的致密双星中，双中子星（DNSs）具有独特的地位，因为它们在银河系中拥有特征明确的本地对应体。然而，由于它们前身星复杂的金属丰度依赖性演化，理解它们更广泛的宇宙学种群仍然具有挑战性。使用详细的双星种群合成代码POSYDON，我们模拟了在宇宙学金属丰度范围内的DNS形成。我们发现，虽然DNS主要通过共同包层演化形成，但金属丰度依赖的径向膨胀和恒星风质量损失将这一路径分叉为不同的子通道，在不同金属丰度下产生系统性不同的并合种群。值得注意的是，我们最具代表性的银河系模型预测的本地并合率与最新的GWTC-5约束大致一致，这表明通过射电脉冲星巡天和GW发射观测到的种群不必存在张力。与先前研究相反，我们证明内在并合效率向低金属丰度方向增加，这一趋势在变化的双星演化假设下是稳健的，尽管驱动这种增强的幅度和底层恒星过程在不同金属丰度区间有所不同。当与宇宙恒星形成历史卷积时，我们的模型揭示大多数并合DNS来源于金属丰度在$\sim 0.1\\,Z_\odot - Z_\odot$范围内的前身星，并有显著的超太阳金属丰度贡献。此外，我们表明低金属丰度下较弱的恒星风产生系统性更对称质量比（$q \gtrsim0.9$）的DNS并合。另外，我们评估了在第三代GW天文台拟议配置中的可探测性。我们的研究为在即将到来的多信使时代解释宇宙学DNS种群提供了一个框架。
英文摘要
Among the compact binaries detected through gravitational wave (GW) emission, double neutron stars (DNSs) hold the unique distinction of having well-characterized local analogs in the Milky Way. However, understanding their broader cosmological population remains challenging due to the complex metallicity-dependent evolution of their progenitors. Using the detailed binary population synthesis code POSYDON, we model DNS formation across a cosmological range of metallicities. We find that while DNSs are predominantly formed through common envelope evolution, metallicity-dependent radial expansion and stellar wind mass loss bifurcates the pathway into distinct subchannels, producing systematically distinct merging populations at different metallicities. Notably, our best representative Galactic models predict local merger rates in broad agreement with the latest GWTC-5 constraints, suggesting that the populations observed via radio pulsar surveys and through GW emission need not be in tension. Contrary to previous studies, we demonstrate that the intrinsic merger efficiency increases toward low metallicities, a trend robust across varying binary evolution assumptions, although the magnitude and the underlying stellar processes driving this enhancement vary across metallicity regimes. When convolved with the cosmic star formation history, our models reveal that the majority of merging DNSs originate from progenitors in the range $\sim 0.1\,Z_\odot - Z_\odot$, with significant supersolar contributions. Furthermore, we show that weaker stellar winds at low metallicities produce DNS mergers with systematically more symmetric mass ratios ($q \gtrsim0.9$). Additionally, we assess detectability within proposed configurations for third-generation GW observatories. Our study provides a framework for interpreting the cosmological DNS population in the upcoming multi-messenger era.
Comments27 pages, 14 figures, submitted to AAS Journals. Comments are welcome
