New atomic and molecular data for astrophysics by high resolution Fourier Transform Spectroscopy

摘要：地面和天基望远镜上的新型高分辨率光谱仪使天文学家能够观测到前所未有质量的天体物理光谱，并且迫切需要足够精确和完整的原子数据来分析这些光谱。尤其重要的是铁族元素（Ti， V, Cr, Mn, Fe, Co, Ni）丰富的谱线。双电离铁基团光谱的原子数据在许多情况下是非常古老的、不完整的和不准确的，在中性和单电离物质的红外光谱的情况下，往往完全缺失。利用我们在帝国理工学院的独特的可见-紫外傅立叶变换（FT）光谱仪和NIST（美国国家标准与技术研究所）傅立叶变换光谱仪，我们将研究这些元素的高分辨率光谱。使用傅立叶变换光谱仪的优点是我们可以在宽光谱范围内以高分辨率测量特定物种的光谱。我们将专注于在波长精度、原子能级、振荡器强度（用于确定天体物理对象中元素丰度）和超精细结构方面至少取得数量级改进的测量。天文学家利用这些原子数据来分析天体物理光谱。一旦测量到原子数据，将立即用于我们正在合作的特定天体物理学项目，例如：低质量恒星，褐矮星和太阳系外行星，热恒星和化学特殊恒星。我们还计划测量用于宇宙学应用的精确波长线：特别是在精细结构常数（基本常数之一）可能的时间变化的研究中。我们所产生的所有新的实验室原子和分子数据都被纳入数据库和模型大气代码，除了英国的天文学家外，还使全世界的天文学家受益。我们向天文学界提供的新的实验室数据意味着，对昂贵获得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（或分子）数据的质量和数量的限制。除了原子数据测量项目外，我们还计划开展一个新的SO2高分辨率分子光谱项目，该项目涉及紫外低温测量，以获得研究火山活动的木卫一（木星的一颗卫星）迫切需要的分子数据。

Summary: New high resolution spectrographs on both ground and space-based telescopes have allowed astronomers to observe astrophysical spectra of unprecedented quality, and have led to an urgent need for atomic data of sufficient accuracy and completeness to analyse these spectra. Particularly important are the abundant, line rich spectra of the iron group elements (Ti, V, Cr, Mn, Fe, Co, Ni). Atomic data of the doubly ionised iron group spectra are in many cases very old, incomplete, and inaccurate, and in the case of the infra red spectra of neutral and singly ionised species are often missing entirely. Using our unique visible-ultraviolet Fourier Transform (FT) spectrometer at Imperial College and the NIST (National Institute Standards & Technology, USA) FT spectrometer we will study high resolution spectra of these elements. The advantages of using an FT spectrometer are that we can measure the spectrum of a particular species at high resolution over a wide spectral range. We will focus on measurements leading to at least order-of-magnitude improvements in wavelength accuracy, atomic energy levels, oscillator strengths (needed for determining abundances of elements in astrophysical objects), and hyperfine structure. Astronomers use these atomic data in analysing astrophysical spectra. Once measured the atomic data will be used immediately in specific astrophysics projects we are collaborating on, examples include: Low mass stars, brown dwarfs and extra solar planets, hot stars, and chemically peculiar stars. We also plan measurements of accurate wavelengths of lines for use in cosmology applications: in particular in investigations of a possible time variation in the fine structure constant, one of the fundamental constants. All the new laboratory atomic and molecular data we produce is incorporated into databases and model atmosphere codes, benefiting astronomers worldwide in addition to those in the UK. The new laboratory 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 (or molecular) data used in their analyses. In addition to the program of atomic data measurements, we plan a new project of high resolution molecular spectroscopy of SO2 which involves low temperature measurements in the UV, to yield molecular data urgently needed for studies of volcanically active Io, a moon of Jupiter.