Astrometric Gravitational-Wave Detection via Stellar Interferometry
Astrometric Gravitational-Wave Detection via Stellar Interferometry
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DOI：
10.1103/physrevd.106.023002
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发表时间：
2022-04
期刊：
影响因子：
5
通讯作者：
M. Fedderke;P. Graham;B. Macintosh;S. Rajendran
中科院分区：
文献类型：
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作者：
M. Fedderke;P. Graham;B. Macintosh;S. Rajendran
我们使用少量恒星的极高精度天体测量来评估 10 nHz 至 1 µ Hz 频段内引力波 (GW) 探测的潜力。特别是，我们认为位于 ~ kpc 距离的非磁性、光度稳定的热白矮星（WD）可能是这种方法的最佳目标。先前对天体引力波探测的研究主要集中在对大量恒星进行不太精确的勘测的潜力上。我们的工作为这个问题提供了另一种优化方法。该频带中有趣的引力波源预计在 h c ∼ 10 − 17 × ( µ Hz /f gw ) 附近的特征应变处。在积分时间 T ∼ 1 /f gw 后，观察这些源所需的天体测量角度精度为 Δ θ ∼ h c 。我们表明，这种类型的 WD 光度中心由于星斑而产生的抖动必然足够小，以允许这种高精度、小 N 的方法。我们讨论了轨道物体引起的恒星反射运动可能产生的噪音，并展示了如何减轻噪音。能够达到必要的天体测量精度的唯一可行的技术是天基恒星干涉仪。这样的未来任务，具有几米规模的收集盘和O（100公里）的基线，足以实现目标精度。该收集器尺寸与某些编队飞行的天基天体仪或出于其他科学原因提出的光学合成孔径成像阵列概念所建议的收集器大致一致。然而，拟议的基线比为这些概念讨论的公里级基线稍大，但我们认为利用此类基线没有根本性的技术障碍。因此，这种类型的任务也有望成为访问该频段有趣的引力波源的少数方法之一。
We evaluate the potential for gravitational-wave (GW) detection in the frequency band from 10 nHz to 1 µ Hz using extremely high-precision astrometry of a small number of stars. In particular, we argue that non-magnetic, photometrically stable, hot white dwarfs (WD) located at ∼ kpc distances may be optimal targets for this approach. Previous studies of astrometric GW detection have focused on the potential for less precise surveys of large numbers of stars; our work provides an alternative optimization approach to this problem. Interesting GW sources in this band are expected at characteristic strains around h c ∼ 10 − 17 × ( µ Hz /f gw ). The astrometric angular precision required to see these sources is ∆ θ ∼ h c after integrating for a time T ∼ 1 /f gw . We show that jitter in the photometric center of WD of this type due to starspots is bounded to be small enough to permit this high-precision, small- N approach. We discuss possible noise arising from stellar reflex motion induced by orbiting objects and show how it can be mitigated. The only plausible technology able to achieve the requisite astrometric precision is a space-based stellar interferometer. Such a future mission with few-meter-scale collecting dishes and baselines of O (100 km) is sufficient to achieve the target precision. This collector size is broadly in line with the collectors proposed for some formation-flown, space-based astrometer or optical synthetic-aperture imaging-array concepts proposed for other science reasons. The proposed baseline is however somewhat larger than the km-scale baselines discussed for those concepts, but we see no fundamental technical obstacle to utilizing such baselines. A mission of this type thus also holds the promise of being one of the few ways to access interesting GW sources in this band.