发表机构
Johns Hopkins University（约翰斯·霍普金斯大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究计算了坍缩星盘分裂产生的亚太阳中子星并合所导致的随机引力波背景能量密度，发现与中心黑洞并合是最响亮的通道，受当前数据约束且可被下一代探测器探测，为盘生亚太阳中子星提供了群体级探针。
AI 中文摘要
最近有人提出，在坍缩星中形成的黑洞周围的、由中微子冷却的吸积盘的分裂，是产生质量远低于标准核心坍缩下限的中子星的天体物理通道。这些盘生天体要么相互并合，要么与中心黑洞并合，而所有这些并合事件在宇宙历史上的叠加便构成了随机引力波背景。在本工作中，我们针对这两种并合通道计算了该背景的能量密度，采用了与观测到的长伽马射线暴速率相关联的形成历史。我们发现，亚太阳中子星与中心黑洞的并合是最响亮的通道，其信号已受到当前数据的约束，并且下一代观测站可探测到；而双中子星通道的强度至多低两个数量级，其中最宽的并合系统仍可被下一代探测器探测到。我们将这些预测与LIGO–Virgo–KAGRA合作组织的第四次观测运行数据进行比较，推导出两个关于其盘产生此类并合的坍缩星比例的上限：一个稳健的上限来自对各向同性背景的未探测，另一个更严格的上限可通过在当前数据中专门搜索可分辨的亚太阳事件来实现。坍缩星盘本身的非轴对称形变所产生的引力波将为坍缩星场景提供额外的独立特征，从而能够与未来的分赫兹探测器进行交叉关联研究。总体而言，这里计算的背景为盘生亚太阳中子星提供了一个群体层面的探针，下一代探测器可将其清晰地纳入视野。
英文摘要
The fragmentation of the neutrino-cooled accretion disks that surround the black holes formed in collapsars has recently been proposed as an astrophysical channel for the production of neutron stars with masses well below the standard core-collapse floor. These disk-born objects merge either with one another or with the central black hole, and the superposition of all such mergers across cosmic history sources a stochastic gravitational-wave background. In this work we compute the energy density of this background for both merger channels, adopting a formation history tied to the observed rate of long gamma-ray bursts. We find that the merger of a subsolar neutron star with the central black hole is the loudest channel, already constrained by current data and within reach of next-generation observatories, while the binary neutron-star channel is at most two orders of magnitude fainter, with its widest binaries remaining accessible to next-generation detectors. Confronting these predictions with the fourth observing run of the LIGO--Virgo--KAGRA Collaboration, we derive two upper bounds on the fraction of collapsars whose disks produce such mergers: a robust one from the non-detection of an isotropic background, and a tighter one that could be achieved by a dedicated search for resolvable subsolar events in current data. Gravitational waves from non-axisymmetric deformations of the collapsar disk itself would provide an additional independent signature for the collapsar scenario, enabling cross-correlation studies with future deci-Hz detectors. Overall, the background computed here provides a population-level probe of disk-born subsolar neutron stars, which next-generation detectors could bring firmly into view.
Comments14 pages, 1 figure
