[论文解读] Beyond Chandra - the X-ray Surveyor

Martin C. Weisskopf, Jessica A. Gaskin+2 more|arXiv (Cornell University)|May 4, 2015

Astrophysical Phenomena and Observations被引用 9

一句话总结

该论文提出了X射线巡天者（X-ray Surveyor），一种下一代X射线天文台，具备与钱德拉望远镜相当的角分辨率，但光子通量大幅提升，采用先进的嵌套薄壳光学系统和一套仪器，包括量热计和大视场成像仪。该研究证明了此类任务在科学上的吸引力和工程上的可行性，使其在即将进行的美国国家航空航天局十年调查中具有高优先级。

ABSTRACT

Over the past 16 years, NASA's Chandra X-ray Observatory has provided an unparalleled means for exploring the universe with its half-arcsecond angular resolution. Chandra studies have deepened our understanding of galaxy clusters, active galactic nuclei, galaxies, supernova remnants, planets, and solar system objects addressing almost all areas of current interest in astronomy and astrophysics. As we look beyond Chandra, it is clear that comparable or even better angular resolution with greatly increased photon throughput is essential to address even more demanding science questions, such as the formation and subsequent growth of black hole seeds at very high redshift; the emergence of the first galaxy groups; and details of feedback over a large range of scales from galaxies to galaxy clusters. Recently, NASA Marshall Space Flight Center, together with the Smithsonian Astrophysical Observatory, has initiated a concept study for such a mission named the X-ray Surveyor. This study starts with a baseline payload consisting of a high resolution X-ray telescope and an instrument set which may include an X-ray calorimeter, a wide-field imager and a dispersive grating spectrometer and readout. The telescope would consist of highly nested thin shells, for which a number of technical approaches are currently under development, including adjustable X-ray optics, differential deposition, and modern polishing techniques applied to a variety of substrates. In many areas, the mission requirements would be no more stringent than those of Chandra, and the study takes advantage of similar studies for other large area missions carried out over the past two decades. Initial assessments indicate that such an X-ray mission is scientifically compelling, technically feasible, and worthy of a high rioritization by the next American National Academy of Sciences Decadal Survey for Astronomy and Astrophysics.

研究动机与目标

• 解决高红移黑洞形成和早期星系群出现中的未解问题。
• 克服当前X射线天文台（如钱德拉）光子通量有限的局限。
• 为下一代X射线天文学开发一项技术上可行、科学上引人注目的任务概念。
• 为即将进行的美国国家航空航天局十年调查争取高优先级。

提出的方法

• 使用先进制造技术设计高分辨率X射线望远镜，采用高度嵌套的薄壳结构。
• 利用可调谐X射线光学系统、差分沉积法以及在各种基底上应用的现代抛光技术。
• 集成多仪器有效载荷，包括X射线量热计、大视场成像仪和色散光栅光谱仪。
• 借鉴以往大视场任务研究的经验，以指导设计和需求制定。
• 通过初步任务性能评估，评估技术可行性与科学回报。
• 基于成熟技术，通过渐进式改进降低风险，构建任务概念。

实验结果

研究问题

• RQ1 下一代X射线天文台能否在实现钱德拉级角分辨率的同时，将通量提升数个数量级？
• RQ2 为研究高红移处的黑洞种子，需要何种仪器与光学配置？
• RQ3 如何通过提升灵敏度，探测从星系到星系群尺度的反馈过程？
• RQ4 何种技术途径可实现面向未来任务的高通量、高分辨率X射线光学系统？
• RQ5 此类任务在科学上是否具有吸引力，且在技术上可行，可纳入下一届十年调查？

主要发现

• X射线巡天者概念在解决高能天体物理学基本问题方面展现出显著的科学吸引力。
• 初步评估确认，该任务可借助先进的薄壳光学制造技术实现技术可行性。
• 该任务将使科学家能够研究极高红移处黑洞种子的形成，这是宇宙学中的一个关键未解难题。
• 包括量热计和大视场成像仪在内的仪器组合，将提供前所未有的光谱与空间动态范围。
• 任务需求在大多数方面并不比钱德拉望远镜更严格，从而可采用类似探路者的发展路径。
• 本研究结论认为，X射线巡天者值得在即将进行的国家科学院十年调查中获得高优先级。