Evidence of early enrichment of the galactic disk by large-scale winds
Evidence of early enrichment of the galactic disk by large-scale winds
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DOI：
10.1093/pasj/62.2.447
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发表时间：
2010-02
影响因子：
2.3
通讯作者：
T. Tsujimoto;J. Bland-Hawthorn;Ken C. Freeman
中科院分区：
文献类型：
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作者：
T. Tsujimoto;J. Bland-Hawthorn;Ken C. Freeman
对银河系恒星的大规模均匀调查可能表明，元素丰度梯度随着宇宙时间而演变，这是一种在现有的银河系化学演化模型（GCE）中没有预见到的现象。如果这种现象在未来的研究中得到证实，我们可以证明这种效应，至少部分是由于曾经丰富了磁盘的大规模风。这些都建立了一个陡峭的丰度梯度内盘（RGC。14 kpc）。在风阶段结束时，通过从晕到盘的贫金属物质的吸积而进行的化学富集逐渐降低了内部区域的金属丰度，而金属丰度的轻微增加则超出了太阳圈。我们的“风+下落”模型解释了内盘丰度梯度的平坦化，与观测结果一致。因此，我们提出，富集大规模的风是一个关键因素的化学演变的磁盘。我们预计，快速平坦的丰度梯度的显著中心凸起的盘星系的标志。
Large-scale homogeneous surveys of Galactic stars may indicate that the elemental abundance gradient evolves with cosmic time, which is a phenomenon that was not foreseen in existing models of Galactic chemical evolution (GCE). If this phenomenon is confirmed in future studies, we can show that this effect, at least in part, is due to largescale winds that once enriched the disk. These set up a steep abundance gradient in the inner disk (RGC . 14kpc). At the close of the wind phase, chemical enrichment through accretion of metal-poor material from the halo to the disk gradually reduced the metallicity of the inner region, whereas a slight increase in the metallicity proceeded beyond the solar circle. Our “wind+infall” model accounts for a flattening of the abundance gradient in the inner disk, in agreement with observations. Accordingly, we propose that enrichment by large-scale winds is a crucial factor in chemical evolution in the disk. We anticipate that rapid flattening of the abundance gradient is the hallmark of disk galaxies with significant central bulges.