Hierarchical formation of bulgeless galaxies - II. Redistribution of angular momentum via galactic fountains Bulgeless discs II
Hierarchical formation of bulgeless galaxies - II. Redistribution of angular momentum via galactic fountains Bulgeless discs II
复制标题
无球核星系的层次结构 - II。
DOI：
10.1111/j.1365-2966.2011.19740.x
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发表时间：
2012
影响因子：
4.8
通讯作者：
Brook C
中科院分区：
文献类型：
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作者：
Brook C
在一个完整的宇宙学流体动力学模拟中，我们形成了一个以140 km s−1旋转的星系，它的特征是两个松散的旋臂和一个棒，这表明它是哈勃型SBc/d星系。 我们表明，在主要合并活动结束后很久，我们模拟的星系没有经典的凸起，具有纯粹的盘轮廓atz= 1。随后形成一个长寿命的酒吧，导致形成一个长期形成的“伪”凸起，最终凸起总光比为0.21。我们发现，在合并时期，大部分失去角动量并福尔斯落在星系中心区域的气体被吹回热晕，其中大部分后来返回，在盘中形成恒星。我们提出，这种通过银河喷泉重新分配角动量的机制，再加上我们以前的研究结果，表明为什么气体流出偏向于具有低角动量，可以解决冷暗物质范式的角动量/无凸起盘问题。
Within a fully cosmological hydrodynamical simulation, we form a galaxy which rotates at 140 km s−1, and it is characterized by two loose spiral arms and a bar, indicative of a Hubble-type SBc/d galaxy. We show that our simulated galaxy has no classical bulge, with a pure disc profile atz= 1, well after the major merging activity has ended. A long-lived bar subsequently forms, resulting in the formation of a secularly formed ‘pseudo-’bulge, with the final bulge-to-total light ratio of 0.21. We show that the majority of gas which loses angular momentum and falls to the central region of the galaxy during the merging epoch is blown back into the hot halo, with much of it returning later to form stars in the disc. We propose that this mechanism of redistribution of angular momentum via a galactic fountain, when coupled with the results from our previous study which showed why gas outflows are biased to have low angular momentum, can solve the angular momentum/bulgeless disc problem of the cold dark matter paradigm.