The evolution of galaxies from primeval irregulars to present-day ellipticals
The evolution of galaxies from primeval irregulars to present-day ellipticals
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DOI：
10.1038/nature04553
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发表时间：
2005-12
期刊：
影响因子：
64.8
通讯作者：
M. Mori;M. Umemura
中科院分区：
文献类型：
--
作者：
M. Mori;M. Umemura
星系的形成被认为是以一种“自下而上”的方式进行的，从小的气体和恒星的形成开始，然后分层合并成巨大的系统。重子气体由于辐射冷却而失去热能，并向新星系的中心福尔斯下落，而超新星则将气体吹出。因此，任何现实的模型都需要对这些过程进行适当的处理，但迄今为止，这还远远不能令人满意。在这里，我们报告了一个模拟，从星系形成的最早阶段，通过动力学松弛期，在这一点上，所产生的星系是在其最终形式的演变。我们的模拟中揭示的气体气泡结构（时间小于3 × 108年）与高红移莱曼-α发射体非常相似。经过109年的演化，这些天体主要是由恒星连续辐射所控制，然后类似于莱曼破裂星系，这是一个高红移的恒星形成星系。在这一点上，比氦重的元素丰度（“金属丰度”）似乎是太阳能的。经过1.3 × 1010年后，这些星系类似于今天的椭圆星系。
Galaxy formation is believed to proceed in a ‘bottom up’ manner, starting with the formation of small clumps of gas and stars that then merge hierarchically into giant systems,. The baryonic gas loses thermal energy by radiative cooling and falls towards the centres of the new galaxies, while supernovae blow gas out,. Any realistic model therefore requires a proper treatment of these processes, but hitherto this has been far from satisfactory. Here we report a simulation that follows evolution from the earliest stages of galaxy formation through the period of dynamical relaxation, at which point the resulting galaxy is in its final form. The bubble structures of gas revealed in our simulation (for times of less than 3 × 108years) resemble closely high-redshift Lyman-α emitters,. After 109years, these bodies are dominated by stellar continuum radiation and then resemble the Lyman break galaxies,, which are high-redshift star-forming galaxies. At this point, the abundance of elements heavier than helium (‘metallicity’) appears to be solar. After 1.3 × 1010years, these galaxies resemble present-day ellipticals.