A NEW CONSTRAINT ON THE PHYSICAL NATURE OF DAMPED LYMAN ALPHA SYSTEMS
A NEW CONSTRAINT ON THE PHYSICAL NATURE OF DAMPED LYMAN ALPHA SYSTEMS
复制标题
阻尼莱曼阿尔法系统物理性质的新约束
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
J. O’Meara
中科院分区：
文献类型：
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作者：
Jeff Cooke;J. O’Meara
星系的形成和演化需要大量的冷中性气体。阻尼Lyα系统（DLAs），在吸收到遥远的类星体和伽马射线爆发，预计是这种气体的主要储层。几十年来，人们对DLA的详细性质进行了广泛的研究，并取得了巨大的成功。然而，它们的大小，理解它们的本质的基础，仍然难以捉摸，因为类星体和伽马射线暴的视线只能探测前景DLAs的相对较小的区域。在这里，我们介绍了一种新的方法来测量扩展背景源的视线中的DLA的全部范围。我们提出了一个高柱密度（log N（H i）= 21.1 ± 0.4 cm−2）DLA在z = 2.4？>覆盖视线背景星系的90%-100%的发光范围。对背景星系大小的估计范围从最小的几kpc 2到100 kpc 2，并表明高柱密度中性气体可以跨越比以前在类星体或伽马射线暴视线中探索的大108-1010倍的连续区域。这里介绍的DLA是第一个从我们的试点调查，搜索莱曼打破和莱曼连续星系在高红移的DLA样本。低光度、大尺寸和质量含量（106-109 M？））和早期的数据表明，DLA包含星系所必需的燃料，许多系统与相对大质量，低光度的原始星系相一致。
The formation and evolution of galaxies require large reservoirs of cold, neutral gas. The damped Lyα systems (DLAs), seen in absorption toward distant quasars and gamma-ray bursts, are predicted to be the dominant reservoirs for this gas. Detailed properties of DLAs have been studied extensively for decades with great success. However, their size, fundamental in understanding their nature, has remained elusive, as quasar and gamma-ray-burst sightlines only probe comparatively tiny areas of the foreground DLAs. Here, we introduce a new approach to measure the full extent of DLAs in the sightlines to extended background sources. We present the discovery of a high-column-density (log N(H i) = 21.1 ± 0.4 cm−2) DLA at z ∼ 2.4 ?> covering 90%–100% of the luminous extent of a line-of-sight background galaxy. Estimates of the size of the background galaxy range from a minimum of a few kpc2 to ∼100 kpc2 and demonstrate that high-column-density neutral gas can span continuous areas 108–1010 times larger than previously explored in quasar or gamma-ray-burst sightlines. The DLA presented here is the first from a sample of DLAs in our pilot survey that searches Lyman break and Lyman continuum galaxies at high redshift. The low luminosities, large sizes, and mass contents (≳106–109 M ⊙ ?> ) implied by this DLA and the early data suggest that DLAs contain the necessary fuel for galaxies, with many systems consistent with relatively massive, low-luminosity primeval galaxies.