宿主星系对搜寻致密天体引力波微透镜效应的影响
Impact of the Host Galaxy on the Search for Gravitational-Wave Microlensing by Compact Objects
- International Centre for Theoretical Sciences, Tata Institute of Fundamental Research（国际理论科学中心，塔塔基础研究所）
- Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）
- The Inter-University Centre for Astronomy and Astrophysics (IUCAA)（大学天文学与天体物理学交叉中心）
- Department of Physics, School of Sciences, National Institute of Technology Andhra Pradesh（安得拉邦国家理工学院理学院物理系）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究探讨宿主星系对引力波微透镜搜索的影响，发现忽略星系效应会降低灵敏度，未来搜索需考虑该效应以约束致密暗物质丰度。
AI中文摘要：
引力波微透镜效应发生在当 intervening 致密天体引起引力波衍射时，在观测信号上留下特征性的频率相关调制。当前对已探测引力波事件中微透镜特征的搜索，包括那些用于约束以致密天体形式存在的暗物质占比的搜索，均假设为孤立点质量透镜（PML）模型。然而，天体物理致密天体通常嵌入在更大的结构中，如星系，其引力势会引入额外的会聚和潮汐剪切，从而扰动透镜信号。在本工作中，我们研究了背景星系在使用PML模型搜索致密天体微透镜效应时的影响。我们将致密天体按照Navarro-Frenk-White密度分布剖面分布在星系内部。我们使用嵌入在恒定会聚和剪切中的PML势来建模微透镜效应，而这些会聚和剪切则由星系透镜的奇异等温球模型计算得出。我们证明，忽略星系效应会系统地降低微透镜搜索的灵敏度，特别是对于高微透镜质量的情况。因此，未来的搜索可能需要纳入透镜星系的额外效应，特别是那些旨在对致密暗物质丰度施加稳健约束的搜索。
英文摘要：
Gravitational-wave (GW) microlensing occurs when an intervening compact object causes diffraction of the GW, imprinting characteristic frequency-dependent modulations on the observed signal. Current searches for microlensing signatures in the detected GW events, including those used to constrain the fraction of dark matter in the form of compact objects, assume an isolated point mass lens (PML) model. However, astrophysical compact objects are typically embedded within larger structures, such as galaxies, whose potentials introduce additional convergence and tidal shear, thereby perturbing the lensed signal. In this work, we study the impact of the background galaxy in the search for microlensing by compact objects using a PML model. We distribute the compact objects inside a galaxy following the Navarro-Frenk-White density profile. We model the microlensing effects using the potential of a PML embedded in a constant convergence and shear, which are, in turn, calculated from a singular isothermal sphere model of the galaxy lens. We demonstrate that neglecting the galaxy's effects can systematically reduce sensitivity in microlensing searches, particularly for high microlens masses. Thus, future searches may need to incorporate the additional effect of the lens galaxy, particularly those aimed at placing robust constraints on the abundance of compact dark matter.
