Hunting for Black Holes with Astrometric Microlensing

利用天体测量微透镜寻找黑洞

• 批准号: 1909641
• 负责人: Jessica Lu
• 金额: $ 36.87万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-06-01 至 2024-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1909641&HistoricalAwards=false
• 关键词: Hunting; Black; Holes; Astrometric; Microlensing

Black holes are one of the most exotic phenomena in astrophysics and are places where the most fundamental physics: gravity and quantum mechanics are tested. The Milky Way Galaxy likely contains between ten million and a billion stellar-mass black holes: those with masses a few times larger than the Sun. Estimating this number and the true distribution of black hole masses can provide important constraints on how black holes form, the existence of primordial black holes from the early universe, and the interpretation of recent gravitational wave detections of merging black hole pairs. To date, no isolated stellar-mass black holes have been definitively detected and only a few dozen black holes have measured masses -- all in binaries. Microlensing, an effect of general relativity where a black hole's gravity lenses the light of a background star observed from Earth, provides a method to detect isolated black holes and measure their masses. A research team at the University of California-Berkeley will carry out sensitive observations of microlensing events to measure both the magnified brightness and the shifted astrometric position, allowing them to precisely measure the mass of the lensing object and determine if it is indeed a black hole or simply a chance lensing event between two normal stars. The outcome is expected to be the first unambiguous detection of an isolated black hole in the Milky Way. As part of the project, the principal investigator (PI) will also enhance the training and diversity of the next generation of scientists and engineers by improving the training for the teachers who will educate them. The PI will start a U. C. Berkeley chapter of the Institute for Scientist and Engineer Educators, which provides a professional development program that enables junior researchers to receive training in inquiry-based teaching methods and education pedagogy. New inquiry activities developed as a result will be also freely disseminated to a broad community of astronomers to multiply the impact of the program.This project aims to develop a new high-precision astrometry experiment to observe long-duration microlensing events and detect and measure the masses of isolated black holes for the first time. Using astrometric observations obtained from the adaptive optics system on the W. M. Keck Observatory, a sample of approximately seven long-duration microlensing events (i.e. candidate black holes) will be monitored in order to measure their lens masses. The expected accuracy on the lens mass is ~10% for a ten solar mass black hole and the predicted black hole detection rate is ~50%. The resulting black hole detection frequency and masses from the proposed survey will be used to constrain the total number of black holes in the Galaxy, their binary fraction, and kick velocities. Finding these isolated black holes would reduce the orders of magnitude uncertainty on the total number of black holes in the Galaxy and constrain theories of black hole formation and evolution. The proposed development of astrometry techniques, needed for astrometric microlensing, will also lay a foundation for new explorations in many areas of astrophysics.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

黑洞是天体物理学中最奇特的现象之一，是测试最基本物理学的地方：重力和量子力学。银河系可能包含一千万至10亿个恒星质量黑洞：质量比太阳大几倍的黑洞。 估计这一数字和黑洞质量的真实分布可以提供有关黑洞的形成，早期宇宙中原始黑洞的存在以及最近合并黑洞对的重力波检测的解释。迄今为止，尚未检测到尚未发现孤立的恒星质量黑洞，只有几十个黑孔测量了质量 - 全都在二进制室中。 微透镜是一般相对论的效果，其中黑洞的重力镜头是从地球观察到的背景恒星的光，它提供了一种检测孤立的黑洞并测量其质量的方法。 加利福尼亚 - 伯克利分校的一个研究团队将对微透析事件进行敏感的观察，以测量放大的亮度和移动的天文位置，从而可以精确地测量镜头对象的质量，并确定它确实是黑洞还是仅仅是两个正常恒星之间的偶然镜头事件。 预计结果将是对银河系中孤立的黑洞的第一个明确检测。 作为该项目的一部分，首席研究员（PI）还将通过改善将教育他们的教师的培训来改善下一代科学家和工程师的培训和多样性。 PI将开设科学家和工程师教育研究所的美国伯克利分会，该分会提供了一项专业发展计划，使初级研究人员能够接受基于询问的教学方法和教育教学法的培训。 因此，开发的新调查活动也将被自由传播到广泛的天文学家社区，以增加该计划的影响。本项目旨在开发新的高精度天文测量实验，以观察长期微透析事件并检测和测量孤立的黑洞的质量。 使用从W. M. Keck天文台上的自适应光学系统获得的天文观测，将监测大约七个长持续微透析事件（即候选黑洞）的样本，以测量其镜头质量。对于十个太阳质量黑洞，晶状体质量的预期准确性约为10％，预测的黑洞检测率为〜50％。所得的黑洞检测频率和拟议调查的质量将用于限制银河系中的黑洞总数，其二元分数和踢速度。找到这些孤立的黑洞将减少银河系中黑洞总数的数量级不确定性，并约束黑洞形成和进化的理论。拟议的天体微透镜所需的天文标准技术的开发也将为许多天体物理学领域的新探索奠定基础。该奖项反映了NSF的法定任务，并被认为值得通过基金会的知识分子优点和更广泛的影响标准通过评估来进行评估。

项目成果

Real-time Likelihood-free Inference of Roman Binary Microlensing Events with Amortized Neural Posterior Estimation

使用摊销神经后验估计对罗马二元微透镜事件进行实时无似然推理

• DOI: 10.3847/1538-3881/abf42e
• 发表时间: 2021
• 期刊: The Astronomical Journal
• 作者: Zhang, Keming;Bloom, Joshua S.;Gaudi, B. Scott;Lanusse, François;Lam, Casey;Lu, Jessica R.
• 通讯作者: Lu, Jessica R.

Supplement: “An Isolated Mass-gap Black Hole or Neutron Star Detected with Astrometric Microlensing” (2022, ApJL, 933, L23)

补充：“用天体测量微透镜检测到的孤立质量隙黑洞或中子星”（2022，ApJL，933，L23）

• DOI: 10.3847/1538-4365/ac7441
• 发表时间: 2022
• 期刊: The Astrophysical Journal Supplement Series
• 作者: Lam, Casey Y.;Lu, Jessica R.;Udalski, Andrzej;Bond, Ian;Bennett, David P.;Skowron, Jan;Mróz, Przemek;Poleski, Radek;Sumi, Takahiro;Szymański, Michał K.
• 通讯作者: Szymański, Michał K.

On the Possibility of Stellar Lenses in the Black Hole Candidate Microlensing Events MACHO-96-BLG-5 and MACHO-98-BLG-6

• DOI: 10.3847/1538-4357/abee83
• 发表时间: 2021-03
• 期刊: The Astrophysical Journal
• 作者: F. Abdurrahman;Haynes Stephens;Jessica R. Lu

The Impact of Initial–Final Mass Relations on Black Hole Microlensing

• DOI: 10.3847/1538-4357/aca09d
• 发表时间: 2022-11
• 期刊: The Astrophysical Journal
• 作者: S. Rose;C. Lam;Jessica R. Lu;M. Medford;M. Hosek;N. Abrams;Emily Ramey;S. S. V. U. O. California-S.-S.-V.-U.-O.-Ca

An Isolated Mass-gap Black Hole or Neutron Star Detected with Astrometric Microlensing

• DOI: 10.3847/2041-8213/ac7442
• 发表时间: 2022-02
• 期刊: The Astrophysical Journal Letters
• 作者: C. Lam;Jessica R. Lu;A. Udalski;I. Bond;D. Bennett;J. Skowron;P. Mróz;R. Poleski;T. Sumi;M. Szymański;S. Kozłowski;P. Pietrukowicz;I. Soszyński;K. Ulaczyk;Ł. Wyrzykowski;S. Miyazaki;D. Suzuki;N. Koshimoto;N. Rattenbury;M. Hosek;F. Abe;R. Barry;A. Bhattacharya;A. Fukui;H. Fujii;Y. Hirao;Y. Itow;R. Kirikawa;I. Kondo;Y. Matsubara;Sho Matsumoto;Y. Muraki;G. Olmschenk;C. Ranc;A. Okamura;Y. Satoh;S. I. Silva;T. Toda;P. Tristram;A. Vandorou;H. Yama;N. Abrams;S. Agarwal;S. Rose;S. Terry