[论文解读] The Milky Way's Supermassive Black Hole: How good a case is it? A Challenge for Astrophysics & Philosophy of Science

A. Eckart, Andreas Huettemann+8 more|arXiv (Cornell University)|Mar 27, 2017

Astrophysical Phenomena and Observations参考文献 31被引用 32

一句话总结

本文利用观测数据、理论模型和哲学框架，评估了人马座A*是超大质量黑洞的证据。文章认为，尽管来自恒星轨道、X射线和红外波段变异性以及未来甚长基线干涉测量（VLBI）与引力波观测的证据强烈支持超大质量黑洞假说，但该结论仍处于证据不足状态，因果关系在评估其科学合法性方面起着核心作用。

ABSTRACT

The compact and, with 4.3+-0.3 million solar masses, very massive object located at the center of the Milky Way is currently the very best candidate for a supermassive black hole (SMBH) in our immediate vicinity. The strongest evidence for this is provided by measurements of stellar orbits, variable X-ray emission, and strongly variable polarized near-infrared emission from the location of the radio source Sagittarius~A* (SgrA*) in the middle of the central stellar cluster. If SgrA* is indeed a SMBH it will, in projection onto the sky, have the largest event horizon and will certainly be the first and most important target of the Event Horizon Telescope (EHT) Very Long Baseline Interferometry (VLBI) observations currently being prepared. These observations in combination with the infrared interferometry experiment GRAVITY at the Very Large Telescope Interferometer (VLTI) and other experiments across the electromagnetic spectrum might yield proof for the presence of a black hole at the center of the Milky Way. It is, however, unclear when the ever mounting evidence for SgrA* being associated with a SMBH will suffice as a convincing proof. Additional compelling evidence may come from future gravitational wave observatories. This manuscript reviews the observational facts, theoretical grounds and conceptual aspects for the case of SgrA* being a black hole. We treat theory and observations in the framework of the philosophical discussions about (Anti)Realism and Underdetermination, as this line of arguments allows us to describe the situation in observational astrophysics with respect to supermassive black holes. Questions concerning the existence of supermassive black holes and in particular SgrA* are discussed using causation as an indispensable element. We show that the results of our investigation are convincingly mapped out by this combination of concepts.

研究动机与目标

• 评估观测与理论证据的强度，以判断人马座A*是否为超大质量黑洞。
• 探讨在关于黑洞的天体物理学主张中，证据不足与实在论所面临的哲学挑战。
• 评估未来来自EHT、GRAVITY及引力波探测器的观测如何影响不确定性问题的解决。
• 从因果推断与科学正当性的角度，重新审视超大质量黑洞存在的合理性。

提出的方法

• 分析来自恒星轨道、可变X射线辐射以及人马座A*偏振近红外辐射的观测数据。
• 应用证据不足与（反）实在论等哲学概念，以解释天体物理学证据。
• 以因果关系为核心标准，评估证据是否足以支持黑洞存在的结论。
• 整合多波段观测结果与EHT、GRAVITY等计划中的实验成果。
• 在观测约束条件下，考察黑洞行为的理论模型。
• 结合实证数据与概念分析，评估黑洞存在性的科学正当性。

实验结果

研究问题

• RQ1 人马座A*是超大质量黑洞的证据是否足以构成科学证明？
• RQ2 证据不足与实在论等哲学概念如何影响对天体物理学观测的解释？
• RQ3 因果关系在多大程度上可作为确认黑洞存在的标准？
• RQ4 未来来自EHT、GRAVITY及引力波探测器的观测将如何影响人马座A*的证据链？
• RQ5 多种观测技术的汇聚能否解决黑洞探测中的证据不足问题？

主要发现

• 位于银河系中心、质量为430±30万倍太阳质量的致密大质量天体，是目前已知最强的超大质量黑洞候选体。
• 恒星轨道测量、可变X射线辐射以及偏振近红外辐射，构成了当前支持人马座A*为黑洞的最强证据。
• 事件视界望远镜（EHT）的VLBI观测有望在直接成像事件视界方面发挥决定性作用。
• 未来的引力波探测器可能为超大质量黑洞的存在提供额外有力证据。
• 证据不足与因果关系的哲学框架有助于厘清当前观测正当性的边界。
• 尽管证据日益充分，人马座A*为黑洞的论断仍处于证据不足状态，凸显了进一步开展观测与概念性审视的必要性。