The rapid formation of a large rotating disk galaxy three billion years after the Big Bang
The rapid formation of a large rotating disk galaxy three billion years after the Big Bang
复制标题
大爆炸三十亿年后大型旋转盘星系的快速形成
DOI：
10.1038/nature05052
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发表时间：
2006-08-17
期刊：
影响因子：
64.8
通讯作者：
Mignoli, M.
中科院分区：
文献类型：
--
作者：
Genzel, R.;Tacconi, L. J.;Mignoli, M.
观测和理论模拟已经建立了年轻宇宙中星系形成和演化的框架。重子气体在坍缩的暗物质晕的中心冷却，形成了星系团;然后，暗物质晕和星系的合并导致了星系质量的分层积累。然而，星系是在什么时间尺度上聚集起来的，以及凸起和盘状结构（现今星系的主要组成部分）是何时以及如何形成的，这些都还不清楚。同样令人困惑的是，最大质量的星系更丰富，并且在早期形成恒星的速度比模型预期的更快。在这里，我们报告了一个代表性的明亮恒星形成星系的高角分辨率观测，当时宇宙只有当前年龄的20%。一个巨大的旋转原盘正在将气体输送到一个不断增长的中央恒星凸起，那里有一个吸积的大质量黑洞。气体的高表面密度、星星形成的高速率和适度年轻的恒星年龄表明，最初非常富含气体的原盘快速组装、分裂和转化为恒星，没有明显的证据表明发生了大合并。
Observations and theoretical simulations have established a framework for galaxy formation and evolution in the young Universe,,. Galaxies formed as baryonic gas cooled at the centres of collapsing dark-matter haloes; mergers of haloes and galaxies then led to the hierarchical build-up of galaxy mass. It remains unclear, however, over what timescales galaxies were assembled and when and how bulges and disks—the primary components of present-day galaxies—were formed. It is also puzzling that the most massive galaxies were more abundant and were forming stars more rapidly at early epochs than expected from models,,,. Here we report high-angular-resolution observations of a representative luminous star-forming galaxy when the Universe was only 20% of its current age. A large and massive rotating protodisk is channelling gas towards a growing central stellar bulge hosting an accreting massive black hole. The high surface densities of gas, the high rate of star formation and the moderately young stellar ages suggest rapid assembly, fragmentation and conversion to stars of an initially very gas-rich protodisk, with no obvious evidence for a major merger.