Detectability of Ultra-compact X-Ray Binaries as LISA Sources
Detectability of Ultra-compact X-Ray Binaries as LISA Sources
复制标题
超紧凑 X 射线双星作为 LISA 源的可探测性
DOI：
10.3847/2041-8213/abae66
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
王博
中科院分区：
文献类型：
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作者：
Chen Wen-Cong;Liu Dong-Dong;王博
超紧凑X射线双星（UCXB）是具有超短轨道周期（通常小于1小时）和贫氢供体星的低质量X射线双星，被认为是潜在的激光干涉仪空间天线（LISA）源。在这项工作中，我们首先使用恒星天体物理学代码中的实验模块来检查 LISA 将检测到的 UCXB 祖先的参数空间。我们的模拟表明，具有中子星和伴星的初始双星，在初始轨道周期小于分叉周期的轨道上，可能演化为UCXB，其中一些会发射LISA可探测到的引力波信号。然而，在10 kpc距离内演化为UCXB-LISA源的双星的初始轨道周期位于非常窄的范围内，即这些LISA源的形成需要对初始参数进行极端的微调。根据特征应变和推导的最大可探测距离，LISA预计可探测到具有观测距离的8个UCXB中的4个源。根据详细的双星演化模型和快速双星演化代码给出的参数空间，估计银河系中作为LISA源出现的UCXB的诞生率为 。考虑到UCXB在球状星团中的贡献，UCXB-LISA源的数量可以达到240-320个。尽管形成条件很严峻，但 LISA 对 UCXB 的可检测性仍然很重要，因为它提供了进行全面的多信使研究的机会。
Ultra-compact X-ray binaries (UCXBs) are low-mass X-ray binaries with ultra-short orbital periods (usually less than 1 hr) and hydrogen-poor donor stars, which are proposed to be potential Laser Interferometer Space Antenna (LISA) sources. In this work, we first employ the Modules for Experiments in Stellar Astrophysics code to examine the parameter space of the progenitors of UCXBs that LISA will detect. Our simulations indicate that the initial binaries with a neutron star and a companion star, in an orbit of initial orbital period smaller than the bifurcation period, could evolve into UCXBs, some of which will emit gravitational wave signals that can be detectable by LISA. However, the initial orbital periods of the binaries that will evolve into UCXB-LISA sources in a distance of 10 kpc are located in a very narrow range, i.e., the formation of these LISA source requires an extreme fine-tuning of initial parameter. According to the characteristic strains and the derived maximum detectable distances, four sources among eight UCXBs with the observed distances are expected to be detected by LISA. Based on the parameter space given by the detailed binary evolution models and the rapid binary star evolution code, the birthrate of UCXBs appearing as LISA sources in the Galaxy is estimated to be . Considering the contribution of UCXBs in globular clusters, the number of UCXB-LISA sources can reach 240–320. Although the formation condition is severe, the detectability of UCXBs by LISA is still significant because it provides an opportunity to pursue full multi-messenger investigations.