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arXiv 1909.03056astro-ph.GA
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ESA Voyage 2050白皮书：星系内部和周围气体相的完整普查，远紫外分光偏振仪是了解星系演化和恒星形成的主要工具

ESA Voyage 2050 white paper: A complete census of the gas phases in and around galaxies, far-UV spectropolarimetry as a prime tool for understanding galaxy evolution and star formation

V. Lebouteiller, C. Gry. H. Yan, P. Richter, B. Godard, E. B. Jenkins, D. Welty, N. Lehner, P. Guillard, J. Roman-Duval, E Roueff, F. Leone, D. Kunth, J. C. How… 展开作者

V. Lebouteiller, C. Gry. H. Yan, P. Richter, B. Godard, E. B. Jenkins, D. Welty, N. Lehner, P. Guillard, J. Roman-Duval, E Roueff, F. Leone, D. Kunth, J. C. Howk, P. Boissé, F. Boulanger, E. Bron, B. James, J. Le Bourlot, F. Le Petit, M. Pieri, V. Valdivia

备注：
This ESA white paper draws from and expands on the following white papers previously submitted for the Astro 2020 Decadal Survey, Gry et al. (2019), Lebouteiller et al. (2019), and Yan et al. (2019). The original ESA white paper was reformatted as a 2-column paper for the present document. (arXiv admin note: substantial text overlap with arXiv:1903.07295, arXiv:1903.06250, arXiv:1903.11065)
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摘要：

远紫外波长范围（912- 2000 A）提供了对许多物质（星际介质（ISM）、环星系介质（CGM）和星系间介质）的原子和分子跃迁的访问，这些物质在跨越电离、密度、温度和分子气体分数的广泛范围内的相位内。远紫外空间望远镜已经能够详细研究银河系中的ISM，这要归功于热恒星紫外光谱中出现的吸收特征，并对ISM所有阶段的组成和物理特性以及影响它们的过程产生了基本的见解。然而，我们还没有设计出一种光谱仪，它能够在分辨率R> 10 ^5、信噪比SNR>500的情况下观察整个UV域。这样的分辨率是必要的，以解决线从冷分子氢和暖金属离子的湍流速度约为1公里s-1，并区分不同的速度分量。未来的紫外光谱研究的银河系ISM必须彻底改变我们的理解ISM作为一个动态的，不稳定的，磁化介质，并上升到目前的理论所带来的挑战。另一个有趣的前景是将银河系的细节水平转移到外部星系的ISM中，特别是在贫金属星系中，ISM的化学成分，物理条件和拓扑结构发生了显着变化，对恒星形成特性产生了显着影响。最后，我们需要能够进行统计分析的背景类星体视线相交的CGM星系在不同的红移和理解气体交换和流动的星系演化的作用。

英文摘要：

(abridged) The far-UV wavelength range (912-2000A) provides access to atomic and molecular transitions of many species the interstellar medium (ISM), circumgalactic medium (CGM), and intergalactic medium, within phases spanning a wide range of ionization, density, temperature, and molecular gas fraction. Far-UV space telescopes have enabled detailed studies of the ISM in the Milky Way thanks to absorption features appearing in the UV spectra of hot stars and yielding fundamental insights into the composition and physical characteristics of all phases of the ISM along with the processes that influence them. However, we have yet to design a spectrometer able to observe the full UV domain at resolving power R>10^5 with a signal-to-noise ratio SNR>500. Such a resolution is necessary to resolve lines from both the cold molecular hydrogen and the warm metal ions with a turbulent velocity of about 1 km s-1, and to differentiate distinct velocity components. Future UV spectroscopic studies of the Milky Way ISM must revolutionize our understanding of the ISM as a dynamical, unstable, and magnetized medium, and rise to the challenge brought forward by current theories. Another interesting prospect is to transpose the same level of details that has been reached for the Milky Way to the ISM in external galaxies, in particular in metal-poor galaxies, where the ISM chemical composition, physical conditions, and topology change dramatically, with significant consequences on the star-formation properties. Finally, we need to be able to perform statistical analyses of background quasar lines of sight intersecting the CGM of galaxies at various redshifts and to comprehend the role of gas exchanges and flows for galaxy evolution.

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