Gas emission lines from damped Lyman-α systems probe galaxy evolution in the early universe. Identifying the hosts of quasar absorbers If the line of sight from Earth to a distant quasar passes through foreground material, some of the quasar's light is absorbed. If a galaxy-sized quantity of gas intervenes, it forms a damped Lyman α system (DLA), visible as absorption lines in the quasar spectrum. Using the Atacama Large Millimeter/Submillimeter Array, Neeleman et al. observed two quasars with known DLAs. They detected emission from gas and dust in two foreground galaxies associated with the DLAs and were able to measure their star-formation rates. Combining these different tracers of DLAs will help us understand how galaxies evolved in the early universe. Science, this issue p. 1285 Gas surrounding high-redshift galaxies has been studied through observations of absorption line systems toward background quasars for decades. However, it has proven difficult to identify and characterize the galaxies associated with these absorbers due to the intrinsic faintness of the galaxies compared with the quasars at optical wavelengths. Using the Atacama Large Millimeter/Submillimeter Array, we report on detections of [C ii] 158-μm line and dust-continuum emission from two galaxies associated with two such absorbers at a redshift of z ~ 4. Our results indicate that the hosts of these high-metallicity absorbers have physical properties similar to massive star-forming galaxies and are embedded in enriched neutral hydrogen gas reservoirs that extend well beyond the star-forming interstellar medium of these galaxies.

中文翻译：

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[C ii] 来自阻尼 Lyman-alpha 系统的宿主星系的 158-μm 发射

来自阻尼 Lyman-α 系统的气体发射线探测了早期宇宙中的星系演化。识别类星体吸收体的宿主 如果从地球到遥远类星体的视线穿过前景物质，类星体的一些光就会被吸收。如果有星系大小的气体介入，就会形成阻尼莱曼 α 系统 (DLA)，在类星体光谱中以吸收线的形式可见。使用 Atacama 大型毫米/亚毫米阵列，Neeleman 等人。观察到两个具有已知 DLA 的类星体。他们在与 DLA 相关的两个前景星系中检测到气体和尘埃的排放，并能够测量它们的恒星形成率。结合这些不同的 DLA 示踪剂将帮助我们了解星系在早期宇宙中是如何演化的。科学，这个问题 p。1285 几十年来，通过对背景类星体的吸收线系统的观察，研究了高红移星系周围的气体。然而，由于在光学波长下与类星体相比，星系固有的微弱性，因此很难识别和表征与这些吸收体相关的星系。使用阿塔卡马大型毫米/亚毫米阵列，我们报告了对 [C ii] 158-μm 线和与两个此类吸收体相关的两个星系的尘埃连续发射的检测，红移为 z ~ 4。我们的结果表明这些高金属度吸收体具有类似于大质量恒星形成星系的物理特性，并嵌入在远远超出这些星系的恒星形成星际介质的富集中性氢气储层中。