[论文解读] Science Impacts of the SPHEREx All-Sky Optical to Near-Infrared Spectral Survey: Report of a Community Workshop Examining Extragalactic, Galactic, Stellar and Planetary Science

Olivier Doré, M. W. Werner+66 more|arXiv (Cornell University)|Jun 22, 2016

Astronomy and Astrophysical Research被引用 39

一句话总结

本文总结了SPHEREx全天近红外光谱巡天的科学潜力，该巡天将对每个6.2×6.2角秒的天空像素提供0.75–5.00 µm波段的高信噪比光谱。该任务将在天体物理学和行星科学领域实现变革性研究，包括精确测量恒星与系外行星参数、绘制星际冰分布图、识别高红移类星体，且与詹姆斯·韦布空间望远镜（JWST）和TESS等未来任务具有强大协同效应。

ABSTRACT

SPHEREx is a proposed SMEX mission selected for Phase A. SPHEREx will carry out the first all-sky spectral survey and provide for every 6.2" pixel a spectra between 0.75 and 4.18 $μ$m [with R$\sim$41.4] and 4.18 and 5.00 $μ$m [with R$\sim$135]. The SPHEREx team has proposed three specific science investigations to be carried out with this unique data set: cosmic inflation, interstellar and circumstellar ices, and the extra-galactic background light. It is readily apparent, however, that many other questions in astrophysics and planetary sciences could be addressed with the SPHEREx data. The SPHEREx team convened a community workshop in February 2016, with the intent of enlisting the aid of a larger group of scientists in defining these questions. This paper summarizes the rich and varied menu of investigations that was laid out. It includes studies of the composition of main belt and Trojan/Greek asteroids; mapping the zodiacal light with unprecedented spatial and spectral resolution; identifying and studying very low-metallicity stars; improving stellar parameters in order to better characterize transiting exoplanets; studying aliphatic and aromatic carbon-bearing molecules in the interstellar medium; mapping star formation rates in nearby galaxies; determining the redshift of clusters of galaxies; identifying high redshift quasars over the full sky; and providing a NIR spectrum for most eROSITA X-ray sources. All of these investigations, and others not listed here, can be carried out with the nominal all-sky spectra to be produced by SPHEREx. In addition, the workshop defined enhanced data products and user tools which would facilitate some of these scientific studies. Finally, the workshop noted the high degrees of synergy between SPHEREx and a number of other current or forthcoming programs, including JWST, WFIRST, Euclid, GAIA, K2/Kepler, TESS, eROSITA and LSST.

研究动机与目标

• 利用首個全天近紅外光譜巡天，識別並編目廣泛的天體物理與行星科學現象。
• 通過整合SPHEREx數據與TESS及Gaia的數據，提高恆星與系外行星參數的測量精度。
• 通過深度、大面積的光譜覆蓋，實現對低金屬量恆星與高紅移類星體等稀有或難以探測天體的發現。
• 通過預選最佳目標，支持與JWST、WFIRST、Euclid和LSST等重大未來任務的協同科學研究。
• 開發增強的數據產品與用戶工具，以最大化SPHEREx遺產數據集的科學回報。

提出的方法

• 舉辦社區研討會，徵求天體物理與行星科學領域專家對SPHEREx數據潛在應用的意見。
• 利用SPHEREx的0.75–5.00 µm光譜巡天（R ~ 41.4（0.75–4.18 µm）和R ~ 135（4.18–5.00 µm）），獲取所有天空像素的高信噪比光譜。
• 利用SPHEREx的靈敏度，實現對2MASS源的信噪比S/N > 50/每頻率單元，以及對3.4和4.8 µm波段最暗的WISE源S/N > 5。
• 整合SPHEREx數據與Gaia、TESS和JWST等任務的多波段數據，以約束恆星參數與系外行星特性。
• 應用光譜光度模型，以提高恆星半徑與質量的測量精度，將關鍵目標的不確定度從約5%降低至約1%。
• 利用SPHEREx的全天覆蓋能力，繪製黃道光圖像，探測星际含碳分子，並通過光譜特徵識別高紅移類星體。

实验结果

研究问题

• RQ1 全天近紅外光譜巡天如何提升恆星與系外行星參數的測量精度，特別是針對M型星系系的恆星？
• RQ2 SPHEREx在識別與表征低金屬量恆星與高紅移類星體等稀有天體方面具有何潛力？
• RQ3 SPHEREx數據如何提升JWST與WFIRST等重大未來任務的目標選擇與科學產出？
• RQ4 SPHEREx在改善宇宙紅外背景及其來源測量方面能發揮多大作用？
• RQ5 SPHEREx數據如何促進對星际與周恆星冰的全新發現，以及對太陽系小天體成分的認識？

主要发现

• SPHEREx將為2MASS星表中所有源提供0.75–5.00 µm波段、每頻率單元S/N > 50的光譜，並對3.4和4.8 µm波段最暗的WISE源實現S/N > 5。
• 該任務將使關鍵目標（如KELT-3）的恆星半徑測量不確定度從約5%降低至約1%，從而使系外行星半徑測量精度提升至約1%。
• SPHEREx將提供首個0.75–5.00 µm波段的全天光譜巡天，光譜分辨率R ~ 41.4（0.75–4.18 µm）和R ~ 135（4.18–5.00 µm）。
• 該巡天將實現對鄰近星系中恆星形成率的綜合研究，繪製出星际脂肪族與芳香族含碳分子的分布圖像，並探測星际與周恆星環境中的冰物質。
• SPHEREx將識別所有eROSITA X射線源，並提供其近紅外光譜，同時實現對全天範圍內星系團的紅移測定。
• SPHEREx與TESS、JWST及Gaia的協同效應將顯著提升各任務的科學回報，特別是在目標選擇優化與參數約束方面。