发表机构
SISSA; INFN-Trieste; IFPU; INAF-IRA; Univ. Heidelberg; Univ. of Trento; INAF-OAR（斯issa国际高等研究院; 意大利国家核物理研究所的里雅斯特分部; 理论物理学前沿研究所; 意大利国家天体物理研究所都灵天文台; 海德堡大学; 特伦托大学; 意大利国家天体物理研究所阿斯科利山天文台）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文应用恒星考古学驱动的星系演化框架StAGE，研究宁静星系及其前身中的双黑洞并合率与引力波背景，发现其贡献可观但与LVK观测存在张力，并预测随机背景可被未来探测器探测。
AI 中文摘要
我们应用StAGE——一个基于恒星考古学的数据驱动星系演化框架——来研究宁静星系（QGs）及其恒星形成前身中的双黑洞（BBH）并合。我们将StAGE的恒星形成与化学增丰历史与预先计算的SEVN双星种群合成目录相结合，推导出BBH并合率密度、其对内禀双星和宿主星系性质的依赖关系，以及相关的随机引力波（GW）背景。我们评估了与恒星考古学预设、公共包层演化和α元素增丰相关的的不确定性。我们发现，宁静星系及其前身可以为宇宙BBH并合率贡献相当大的一部分。对于我们探索的大多数双星演化预设，我们强调了与当地LVK推断的并合率之间的张力，这突显了重新审视基础建模中某些假设的必要性。大多数BBH形成于中等亚太阳金属丰度，$Z\lesssim Z_\odot/3$，而其并合时的宿主恒星质量通常为$M_\star\lesssim10^{11}\\,M_\odot$。在$z\gtrsim2$时，宿主主要位于星系主序上，而星暴和熄灭的后代在较低红移处贡献逐渐增加。孤立双星大体上再现了观测到的主质量与啁啾质量分布的主体，但预测在约$40-50\\,M_\odot$以上迅速下降，对LVK推断的最高质量系统提供的支持甚少。年轻星团和球状星团中的动力学形成可以填补这一区间，但也会增加总并合率密度，从而加剧了与我们在此采用的基准星团归一化相关的LVK张力。最后，预测的随机背景接近计划中LVK升级的预期灵敏度，并在爱因斯坦望远镜的探测范围之内。
英文摘要
We apply StAGE, a data-driven galaxy-evolution framework based on stellar archaeology, to study binary black hole (BBH) mergers in quiescent galaxies (QGs) and their star-forming progenitors. We combine StAGE star-formation and chemical-enrichment histories with pre-computed SEVN binary population-synthesis catalogs to derive the BBH merger-rate density, its dependence on intrinsic binary and host-galaxy properties, and the associated stochastic gravitational-wave (GW) background. We assess uncertainties related to stellar-archaeology prescriptions, common-envelope evolution, and $α$-enhanced abundances. We find that QGs and their progenitors can contribute a sizeable fraction of the cosmic BBH merger rate. For most of the binary-evolution prescriptions explored here, we highlight a tension with the local LVK-inferred merger rates, underscoring the need to revisit some assumptions in the underlying modeling. Most BBHs form at moderately subsolar metallicities, $Z\lesssim Z_\odot/3$, while their merger-time hosts typically have stellar masses $M_\star\lesssim10^{11}\,M_\odot$. At $z\gtrsim2$, hosts lie mainly on the galaxy main sequence, whereas starbursting and quenching descendants contribute increasingly toward lower redshift. Isolated binaries broadly reproduce the observed bulk of the primary- and chirp-mass distributions, but the predictions decline rapidly above $\sim 40-50\,M_\odot$, providing little support for the highest-mass systems inferred by LVK. Dynamical formation in young and globular clusters can populate this regime, but also increases the total merger-rate density, exacerbating the tension with LVK for the fiducial cluster normalizations adopted here. Finally, the predicted stochastic background approaches the projected sensitivity of planned LVK upgrades and lies within reach of the Einstein Telescope.
Comments53 pages, 18 figures
