标题： 解决驱动恒星形成的Damped Lyman-α系统的HI问题 显示英文标题

标题： Resolving the HI in Damped Lyman-α systems that power star-formation

摘要： 富含密集原子气体（主要是氢）的星系团，在红移为3时包含大约90%的中性气体，并且占宇宙总重子含量的2-3%。 这些强吸收Lyman-${\alpha}$系统（之所以被称为强吸收是因为它们会吸收来自内部和背景源的Lyman-${\alpha}$光子）已经被研究了几十年，但仅限于背景类星体和伽马射线暴光谱中的吸收线。 这样的“笔状光束”并不能限制系统的物理范围。 在这里，我们报告了一个亮度较高、引力透镜效应明显的红移为2.7的星系的积分场光谱，该星系有两组前景强吸收Lyman-${\alpha}$系统。 这些系统在$>$238$kpc^2$的范围内延伸，在$<$3千秒差距尺度上中性氢柱密度的变化超过一个数量级。 柱密度的平均值为$10^{20.46}$-$10^{20.84} cm^{-2}$，总质量为$> 5.5 \times 10^{8}$-$1.4 \times 10^{9} M_{\odot}$，表明它们包含了下一代恒星形成的必要燃料，这与红移为$>$的相对大质量、低光度的原始星系一致。 显示英文摘要

摘要： Reservoirs of dense atomic gas (primarily hydrogen), contain approximately 90 percent of the neutral gas at a redshift of 3, and contribute to 2-3 percent of the total baryons in the Universe. These damped Lyman-${\alpha}$ systems (so called because they absorb Lyman-${\alpha}$ photons from within and from background sources) have been studied for decades, but only through absorption lines present in the spectra of background quasars and gamma-ray bursts. Such pencil beams do not constrain the physical extent of the systems. Here, we report integral-field spectroscopy of a bright, gravitationally lensed galaxy at a redshift of 2.7 with two foreground damped Lyman-${\alpha}$ systems. These systems are $>$ 238 $kpc^2$ in extent, with column densities of neutral hydrogen varying by more than an order of magnitude on $<$ 3 kpc-scales. The mean column densities are $10^{20.46}$ - $10^{20.84} cm^{-2}$ and the total masses are $> 5.5 \times 10^{8}$ - $1.4 \times 10^{9} M_{\odot}$, showing that they contain the necessary fuel for the next generation of star formation, consistent with relatively massive, low-luminosity primeval galaxies at redshifts $>$ 2.