LISA任务结束后合并的极端质量比旋进源中可探测的比例是多少？
What Fraction of Extreme Mass Ratio Inspirals That Merge After the LISA Mission Ends Are Detectable?
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中文总结 AI 辅助
本研究计算LISA可探测EMRI中任务结束后才坠入黑洞的比例，发现四年任务中约占四分之一，十年任务中约占六分之一，并指出需开发适合此类源的探测算法。
中文摘要 AI 辅助
恒星质量致密天体旋进到星系核中的大质量黑洞（称为“极端质量比旋进”，简称EMRI）将成为激光干涉空间天线（LISA）的一类重要源。恒星质量致密天体在坠入其大质量黑洞之前，可以在毫赫兹频带内辐射数年乃至数十年，因此LISA能够探测到的EMRI中，有相当一部分在任务结束时仍处于旋进阶段。我们计算了可探测EMRI中在任务结束后坠入黑洞的比例，并针对这些源，计算了它们随各种参数（如任务后寿命）的分布。为此，我们从天体物理动机驱动的族群中抽取样本，对完全相对论的Kerr FastEMRIWaveforms轨迹进行向后积分，以确定给定的坠入时间，并计算在四年标称观测窗口和十年扩展观测窗口内的完整LISA响应。我们计算了在信噪比（SNR）阈值ρ=10、20和30下，可探测比例作为坠入时间的显式函数。我们发现，在四年任务中，ρ>20时，任务后EMRI约占LISA可探测族群的四分之一；在十年扩展任务中，约占六分之一。在我们运行的大质量黑洞自旋和次级质量范围内，ρ>20时，窗口内可探测比例变化近六倍，而四年任务中该比例保持在25%至33%之间，十年任务中保持在13%至20%之间。搜索在任务结束后超过约1年才坠入的EMRI，可能需要与搜索任务期间坠入的EMRI不同的算法，而任务后探测占所有探测的相当大比例这一事实，使得开发适合它们的探测管线变得紧迫。
英文摘要
Stellar-mass compact objects spiraling into massive black holes in galactic nuclei (referred to as "extreme-mass-ratio inspirals", or EMRIs) will be an important class of sources for the Laser Interferometer Space Antenna (LISA). A stellar-mass compact object can radiate in the millihertz band for years to decades before it plunges into its massive black hole, so a substantial fraction of the EMRIs that LISA can detect will still be inspiraling when the mission ends. We calculate what fraction of detectable EMRIs will plunge after the mission ends, and for those we calculate how they are distributed as a function of various parameters, such as their post-mission lifetime. To do this, we draw from astrophysically motivated populations, backward-integrate fully relativistic Kerr FastEMRIWaveforms trajectories for a given time to plunge, and compute the full LISA response over both the four-year nominal and ten-year extended observing windows. We calculate the detectable fraction as an explicit function of time to plunge at signal-to-noise ratio (SNR) thresholds of $ρ=10$, 20, and 30. We find that post-mission EMRIs are roughly one in four of the LISA-detectable population at $ρ>20$ over the four-year mission, and roughly one in six over the ten-year extended mission. The in-window detectable fraction varies by nearly a factor of six at $ρ>20$ across the massive black hole spins and secondary masses we ran, while the share stays between 25% and 33% for the four-year mission and between 13% and 20% for the ten-year one across all of them. The search for EMRIs that plunge more than $\sim 1$ year after the mission ends may require a different algorithm than the one used for EMRIs that plunge during the mission, and the fact that post-mission detections are a substantial fraction of all detections gives some urgency to developing a detection pipeline suitable for them.
发表机构
- Oregon State University（俄勒冈州立大学）
- Universities Space Research Association（大学空间研究协会）
- NASA Marshall Space Flight Center（美国国家航空航天局马歇尔太空飞行中心）
- California Institute of Technology（加州理工学院）
- University of Southampton（南安普顿大学）
机构由 AI 辅助整理，请以论文原文为准。
