z~3处作为隐藏结构信标的氢I吸收体：原星团附近的多组分富金属吸收系统
H I Absorbers as Beacons of Hidden Structure at $z \sim 3$: Multi-Component, Metal-Rich Absorption System near a Protocluster
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中文总结 AI 辅助
本研究在z~3处发现偏移原星团60cMpc的富金属多组分氢I吸收体，提出两种物理情景，证实强氢I吸收体可作为早期宇宙大质量结构的信标。
中文摘要 AI 辅助
氢I气体（H I gas）可示踪大尺度结构，是恒星形成的主要燃料。高红移（high-z）原星团是研究宇宙中最巨大结构形成过程中氢I气体如何吸积与消耗的理想实验室，但其氢I气体的分布与物理状态仍有诸多未知。我们研究了一个罕见构型：一个原星团候选体位于红移z=3.09的类星体后方。我们的光谱观测证实了一个红移z=3.079的原星团，但在背景类星体光谱中未发现对应的强氢I吸收。反而，我们偶然发现了一个红移z~3.01的显著氢I吸收特征，其位置偏移原星团中心约60共动百万秒差距（cMpc）。该吸收覆盖了约2000 km/s（约40 cMpc）的极宽速度范围，与已证认的成员星系无关联。详细运动学建模显示，该吸收由五个不同组分构成，而非单一云团。此外，其中一个组分呈现超太阳金属丰度，即[O/H]=+1.19⁺⁰.⁹¹₋₀.₇₈。我们为这个独特系统提出两种物理情景：（1）视线方向上存在另一个隐藏的大质量原星团；（2）由单个大质量星系驱动的富金属外流与贫金属内流。该发现表明，尽管原星团并非都与强氢I吸收相关，但对强氢I吸收体的搜寻可作为信标，用于揭示早期宇宙中的大质量富金属原星团或复杂气体运动学。
英文摘要
H I gas traces the large-scale structure and provides the primary fuel for star formation. High-$z$ protoclusters are ideal laboratories to study how H I gas is accreted and consumed during the formation of the most massive structures in the Universe. However, much remains unknown about the distribution and physical state of their H I gas. We examine a rare configuration in which a protocluster candidate is located in front of a quasar at $z=3.09$. Our spectroscopic campaign confirms a protocluster at $z=3.079$: however, no corresponding strong H I absorption is found in the background quasar spectrum. Instead, we serendipitously discover a prominent H I absorption feature at $z\sim 3.01$, offset by $\sim 60$ cMpc from the centre of the protocluster. Spanning an exceptionally broad velocity range of $\sim 2000$ km s$^{-1}$ ($\sim 40$ cMpc), this absorption is decoupled from the confirmed member galaxies. Detailed kinematic modelling reveals this absorption comprises five distinct components rather than a single cloud. Moreover, one of these components exhibits a super-solar metallicity ($[\mathrm{O/H}] = +1.19^{+0.91}_{-0.78}$). We propose two physical scenarios for this unique system: (1) an additional, hidden massive protocluster along the line of sight, and/or (2) metal-rich outflows and metal-poor inflows driven by a single massive galaxy. The discovery highlights that while protoclusters are not universally associated with strong H I absorption, targeting the strong H I absorbers may serve as a beacon for uncovering massive, metal-rich protoclusters or complex gas kinematics in the early Universe.
发表机构
- The University of Tokyo（东京大学）
- Shinshu University（信州大学）
- Tohoku University（东北大学）
- Hosei University（法政大学）
- National Astronomical Observatory of Japan（日本国立天文台）
机构由 AI 辅助整理，请以论文原文为准。
