Ultra-short-period massive black hole binary candidates in LSST as LISA ‘verification binaries’
Ultra-short-period massive black hole binary candidates in LSST as LISA ‘verification binaries’
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LSST 中作为 LISA“验证双星”的超短周期大质量黑洞双星候选者
DOI：
10.1093/mnras/stab1856
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发表时间：
2021
影响因子：
4.8
通讯作者：
Haiman, Zoltán
中科院分区：
文献类型：
--
作者：
Xin, Chengcheng;Haiman, Zoltán
Vera C. Rubin天文台的遗留时空调查（LSST）预计将发现数千万个类星体。其中很大一部分可能是由合并的大质量黑洞（MBH）双星提供动力，因为许多类星体被认为是由合并引发的。我们表明，在对类星体的光度函数、寿命和双星分数的合理假设下，我们预计完整的LSST类星体目录将包含2000万到1亿个紧密的MBH双星，质量m = 105-9M⊙，红移z= 0-6，轨道周期p = 1-70 d。它们的光曲线预计具有明显的周期性，这可以自信地与随机的红噪声变异性区分开来，因为LSST将覆盖数十甚至数百个周期。其中10-150个超紧（P > 1 d）双星类星体中的一小部分将在~ 5-15年内演化到mHz引力波频段，并可以被lisa探测到。因此，它们可以被视为“LISAverification双星”，类似于短周期的银河紧天体双星。实际的问题是如何在大量的类星体中找到这些“大海捞针”：这可能需要为此目的量身定制的协同添加分析。
The Legacy Survey of Space and Time (LSST) by the Vera C. Rubin Observatory is expected to discover tens of millions of quasars. A significant fraction of these could be powered by coalescing massive black hole (MBH) binaries, since many quasars are believed to be triggered by mergers. We show that under plausible assumptions about the luminosity functions, lifetimes, and binary fractions of quasars, we expect the full LSST quasar catalogue to contain between 20 and 100 million compact MBH binaries with massesM= 105–9M⊙, redshiftsz= 0–6, and orbital periodsP= 1–70 d. Their light-curves are expected to be distinctly periodic, which can be confidently distinguished from stochastic red-noise variability, because LSST will cover dozens, or even hundreds of cycles. A very small subset of 10–150 ultracompact (P≲ 1 d) binary quasars among these will, over ∼5–15 yr, evolve into the mHz gravitational-wave frequency band and can be detected byLISA. They can therefore be regarded as ‘LISAverification binaries’, analogous to short-period Galactic compact-object binaries. The practical question is how to find these handful of ‘needles in the haystack’ among the large number of quasars: this will likely require a tailored co-adding analysis optimized for this purpose.