Direct detection of extragalactic background light by optical and near-infrared observations from deep space

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K14765
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 16010:Astronomy-related
• Research Institution: Kyushu Institute of Technology (2020-2021); Kanazawa University (2019)
• Principal Investigator: SANO Kei 九州工業大学, 大学院工学研究院, 助教 (70802908)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 光赤外線天文学 / 反射望遠鏡 / 宇宙背景放射 / 黄道光

Outline of Final Research Achievements

Extragalactic background light (EBL) is integrated radiation out of Milky Way and is crucial observable quantity to reveal the cosmic star formation history. From visible to near-infrared wavelengths, zodiacal light, sunlight scattered by interplanetary dust, exists as the brightest foreground emission in the near-earth orbit and this situation causes large uncertainty in the EBL measurement. In the present study, we developed a telescope for the EBL observation from deep space where the zodiacal light is fainter. We designed wide-field optics composed of three aspherical mirrors and made them by machining aluminum alloy. We evaluated the optical performance of the optics by inserting parallel light.

Free Research Field

天文学

Academic Significance and Societal Importance of the Research Achievements

赤外線による天文観測では、観測装置からの熱放射を低減するために望遠鏡を冷却する必要がある。レンズ光学系の場合、冷却時の熱収縮により光学的なアライメントが崩れ、結像性能が悪化する可能性がある。本研究で開発したミラーのみを用いた反射光学系は、相似収縮によって冷却時にも光学的なアライメントが保たれるという利点がある。今後、宇宙背景放射の観測に限らず、他の赤外線天文観測でも同様の光学系の使用が期待される。