ROLE OF GALACTIC GASEOUS HALOS IN RECYCLING ENRICHED WINDS FROM BULGES TO DISKS: A NEW BULGE–DISK CHEMICAL CONNECTION
ROLE OF GALACTIC GASEOUS HALOS IN RECYCLING ENRICHED WINDS FROM BULGES TO DISKS: A NEW BULGE–DISK CHEMICAL CONNECTION
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DOI：
10.1088/0004-637x/692/1/l24
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发表时间：
2009-01
期刊：
影响因子：
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通讯作者：
K. Bekki;T. Tsujimoto;M. Chiba
中科院分区：
文献类型：
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作者：
K. Bekki;T. Tsujimoto;M. Chiba
我们首次证明，盘星系的气体晕可以发挥至关重要的作用，在回收富含金属的气体喷出的凸起，从而促进化学演化的磁盘。我们的数值模拟表明，如果气体晕的平均密度（ρhg）高达10−5 cm−3，则由于气体喷出物和气体晕之间的流体动力学相互作用，盘星系中来自凸起的富金属星风可以吸积到薄盘上。通过恒星风从球壳中喷射出来，然后吸积到盘上的气体总量主要取决于ρhg和恒星风的初速度。对于一组合理的模型参数，尺度长度为ad的盘星系中大约0.1%的气态喷出物可以吸积到R 2.5ad左右的盘上。我们讨论了这些结果的背景下，令人惊讶的高金属丰度的太阳附近的星系盘星的起源。我们还讨论了这些结果对不同ρhg的盘星系在不同星系环境中化学演化的影响。
We demonstrate for the first time that gaseous halos of disk galaxies can play a vital role in recycling metal-rich gas ejected from the bulges and thus in promoting the chemical evolution of the disks. Our numerical simulations show that metal-rich stellar winds from bulges in disk galaxies can be accreted onto the thin disks owing to hydrodynamical interaction between the gaseous ejecta and the gaseous halos, if the mean densities of the halos (ρhg) are as high as 10−5 cm−3. The total amount of gas that is ejected from a bulge through a stellar wind and then accreted onto the disk depends mainly on ρhg and the initial velocity of the stellar wind. About ∼1% of gaseous ejecta from bulges in disk galaxies of scale length ad can be accreted onto disks around R ∼ 2.5ad for a reasonable set of model parameters. We discuss these results in the context of the origin of the surprisingly high metallicities of the solar neighborhood disk stars in the Galaxy. We also discuss some implications of the present results in terms of chemical evolution of disk galaxies with possibly different ρhg in different galaxy environments.