A New World Class Infrared Spectrometer for Fundamental Atomic Data for Astrophysics

用于天体物理学基础原子数据的新型世界级红外光谱仪

• 批准号: ST/X005100/1
• 负责人: Juliet Pickering
• 金额: $ 34.9万
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FX005100%2F1
• 关键词: New; World; Class; Infrared; Spectrometer

Modern astronomical spectra are being recorded at unprecedented resolutions in the infrared (IR), visible and ultraviolet (UV) regions by both ground- and space-based telescopes including JWST, ELT, VLT, HST, Keck II, Subaru, UKIRT. The analysis of the spectra recorded by these multi-billion-pound instruments requires laboratory atomic data of at least matching accuracy and completeness. However, for many elements and ionisation states, the existing atomic data date back over 50 years, based on grating and even prism spectrometers. Spectroscopy techniques have improved enormously since then, but the large-scale effort needed to produce new high-resolution, high-accuracy atomic data has meant that the atomic database has lagged behind the needs of the astrophysics and astronomy communities. In many cases, order-of-magnitude improvements in accuracy of atomic data are required for unambiguous identification of all features of interest in an astrophysical spectrum and meaningful interpretation of the astronomical spectra. It is not possible to theoretically calculate atomic data with sufficient precision for analyses of high-resolution astrophysical spectra, and so experimental spectroscopy is the only method to generate atomic data of the necessary accuracy. The Imperial College Spectroscopy Group has a strong track record in significantly improving atomic data with Fourier Transform (FT) spectroscopy. Previously, our work was focussed on the visible and UV spectral regions, with spectra measured using our record-holding vacuum UV (VUV) FT spectrometer. The capital funding of this grant will enable us to increase our capabilities into the infrared (IR) through the addition of a world-class, high-resolution FT spectrometer tailored to the IR spectral region. This vital addition to our facility, in combination with our existing unique visible-ultraviolet FT spectrometer, means that we will be able to study high-resolution spectra of astrophysically important elements across the entire IR-visible-UV region. The timing of this increase in spectral coverage has come just as the IR is growing tremendously in importance for astronomers, with new telescopes, such as the JWST, launched with unprecedented capabilities in the IR region.We will focus on measurements leading to at least order-of-magnitude improvements in wavelength accuracy, atomic energy levels, log(gf)s (transition probabilities, needed for determining chemical abundances of elements in astrophysical objects), and isotope and hyperfine structure (needed to model lines accurately and, again, obtain reliable abundance estimates). The much greater resolution of FT spectroscopy, compared to the best grating spectrometers used in the past, provides wavelengths and energy levels accurate to at least parts in 108, log(gf)s accurate to a few percent, and resolved line broadening effects such as isotope and hyperfine structure. Our atomic data are relevant to many STFC Challenge questions such as: "How do stars and galaxies evolve?", "How does the Sun and other stars work and what drives their variability?" and "What effects do the Sun and other stars have on their local environment?". All the new laboratory atomic data produced by the ICL Spectroscopy Group is incorporated into atomic databases and stellar model atmosphere codes, benefiting astronomers worldwide in addition to those in the UK. The new IR spectrometer will allow our Group to continue our world leading research into the new era of IR astronomical discoveries. Our aim is that the new laboratory atomic data we provide to the astronomical community means that analyses of expensively obtained modern astrophysical spectra will no longer be limited by the quality and quantity of atomic data used in their analyses.

现代天文光谱正在以前所未有的分辨率记录在红外（IR），可见光和紫外（UV）区域的地面和空间望远镜，包括JWST，ELT，VLT，HST，Keck II，Subaru，UKIRT。对这些数十亿磅重的仪器记录的光谱进行分析，需要实验室的原子数据，这些数据至少要具有匹配的准确性和完整性。然而，对于许多元素和电离状态，现有的原子数据可以追溯到50多年前，基于光栅甚至棱镜光谱仪。从那时起，光谱技术有了很大的改进，但产生新的高分辨率，高精度原子数据所需的大规模努力意味着原子数据库已经落后于天体物理学和天文学社区的需求。在许多情况下，原子数据的准确性需要提高一个数量级，以便明确地识别天体物理光谱中所有感兴趣的特征，并对天文光谱进行有意义的解释。理论上不可能计算出足够精确的原子数据来分析高分辨率的天体物理光谱，因此实验光谱学是产生必要精度的原子数据的唯一方法。帝国理工学院光谱组在显著改善傅里叶变换（FT）光谱的原子数据方面有着良好的记录。以前，我们的工作集中在可见光和紫外光谱区域，使用我们的记录保持真空紫外（VUV）FT光谱仪测量光谱。这笔赠款的资本资金将使我们能够通过增加针对红外光谱区域量身定制的世界一流的高分辨率FT光谱仪来提高我们在红外（IR）方面的能力。这对我们的设施至关重要，与我们现有的独特的可见-紫外FT光谱仪相结合，意味着我们将能够研究整个红外-可见-紫外区域的天体物理重要元素的高分辨率光谱。光谱覆盖范围增加的时机正好是红外对天文学家的重要性日益增加的时候，新的望远镜，如JWST，在红外区域具有前所未有的能力。我们将专注于测量，导致波长精度，原子能级，log（gf）s（转移概率，需要确定天体物理物体中元素的化学丰度），以及同位素和超精细结构（需要精确地模拟谱线，并再次获得可靠的丰度估计）。与过去使用的最好的光栅光谱仪相比，FT光谱仪的分辨率更高，提供了至少精确到108分之一的波长和能级，精确到百分之几的log（gf）s，以及分辨的谱线展宽效应，如同位素和超精细结构。我们的原子数据与许多STFC挑战问题相关，例如：“恒星和星系如何进化？太阳和其他恒星是如何工作的，是什么驱动了它们的变化？太阳和其他恒星对它们周围的环境有什么影响？". ICL光谱学小组产生的所有新实验室原子数据都被纳入原子数据库和恒星模型大气代码中，除了英国的天文学家之外，还使世界各地的天文学家受益。新的红外光谱仪将使我们的集团继续我们的世界领先的研究进入新时代的红外天文发现。我们的目标是，我们向天文学界提供的新的实验室原子数据意味着，对昂贵的现代天体物理光谱的分析将不再受到分析中使用的原子数据的质量和数量的限制。