Development of Millimetric Adaptive Optics

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K20287
• Project/Area Number (Other): 17H06206 (2017-2019)
• Research Category: Grant-in-Aid for Challenging Research (Pioneering)
• Allocation Type: Multi-year Fund (2020); Single-year Grants (2017-2019)
• Research Field: Astronomy and related fields
• Research Institution: Nagoya University
• Principal Investigator: Tamura Yoichi 名古屋大学, 理学研究科, 准教授 (10608764)
• Co-Investigator(Kenkyū-buntansha): 川邊 良平 国立天文台, 科学研究部, 教授 (10195141)
• Project Period (FY): 2017-06-30 – 2022-03-31
• Keywords: 電波天文学 / 補償光学 / ミリ波 / 電波望遠鏡 / 計測工学

Outline of Final Research Achievements

In the construction of radio telescopes, it is important to increase the diameter and frequency of antennas while maintaining the accuracy of the mirror surface in order to open up new fields of astronomy. In this study, we conducted basic research on "millimeteric adaptive optics", an optical system that can be installed on existing or future ground-based submillimeter-wave telescopes to compensate for the loss of mirror surface accuracy due to wind loading, thermal deformation, and gravitational deformation in real time. We proposed a wavefront sensor using aperture-plane interferometry, which is an application of a native wavefront sensing technique in radio astronomy, and developed a low-frequency (20 GHz) and small-element (5-element) wavefront sensor, which was installed on the Nobeyama 45-m telescope. As a result, real-time wavefront measurement with an accuracy of 8 μm r.m.s. was demonstrated.

Free Research Field

電波天文学

Academic Significance and Societal Importance of the Research Achievements

ミリ波・サブミリ波は、あらゆる天体の材料であるガスや塵や、高温のプラズマの検出に長けている。ミリ波補償光学の実現は、将来の大型サブミリ波望遠鏡の実現に直結し、引いては世界最大のサブミリ波干渉計ALMAと同等の集光力を持ちながら、視野を10^6倍に、分光帯域幅を10^2倍に拡大する、電波天文学の悲願ともいえる宇宙探査性能の獲得につながると期待される。これは、惑星科学、星形成論、星間化学、宇宙マイクロ波背景放射や銀河・銀河団の探索とそれを用いた宇宙論研究など、波及効果が高い。本研究成果は、既存・将来のミリ波・サブミリ波望遠鏡の大型化・高周波化に分け隔てなく応用し、性能を向上させることが可能である。