Comparing galaxy morphology in hydrodynamical simulation and in semi-analytic model
Comparing galaxy morphology in hydrodynamical simulation and in semi-analytic model
复制标题
比较流体动力学模拟和半解析模型中的星系形态
DOI：
10.1093/mnras/stz529
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发表时间：
2019
影响因子：
4.8
通讯作者：
Pan Jun
中科院分区：
文献类型：
--
作者：
Wang Lan;Xu D;an;Gao Liang;Guo Qi;Qu Yan;Pan Jun
我们比较星系形态预测的插图流体动力学模拟和半解析模型（SAM）嫁接在晕合并树的插图暗物质模拟。根据光度轮廓和运动学膨胀率对Illustris星系进行了形态分类，SAM星系根据膨胀率对恒星总质量的比率进行了形态分类。对于Illustris星表中的晚型星系，SAM模型中的大部分对应星系具有相同的类型，并且对于较低质量的星系，两个模型之间的一致性较高。对于早型（ET）星系在插图，除了大多数大质量星系的一致性是相当低的同行。通过详细比较一些匹配的银河系质量的星系对在Illustris和SAM模型的生长历史，我们注意到两个方面的差异，在确定星系形态之间的两个星系形成的实现。首先，在SAM中，大合并和频繁的小合并导致凸起的增长，并把星系变成ET，而凸起的形成并不像在SAM中的Illustris星系那样与合并紧密相关。此外，卫星恒星的质量在与中央星系合并之前会因潮汐剥离而显著减少，而在SAM模型中则不会减少。这导致在插图模拟中，大（恒星）质量比的合并较少，合并对塑造星系形态的影响较小。
We compare galaxy morphology predicted by the Illustris hydrodynamical simulation and a semi-analytic model (SAM) grafted in the halo merger trees from the Illustris-Dark matter simulation. Morphology is classified according to the luminous profile and the kinematic bulge-to-total ratio for Illustris galaxy, and the bulge-to-total stellar mass ratio for SAM galaxy. For late-type galaxies in the Illustris catalogue, most of their counterparts in the SAM model have the same type, and the consistency between two models is higher for lower mass galaxies. For early-type (ET) galaxies in Illustris, the consistency is quite low for the counterparts except for most massive galaxies. By comparing in detail the growth histories of some matched galaxy pairs of Milky Way mass in Illustris and the SAM model, we notice two aspects of differences in determining galaxy morphology between the two galaxy formation implementations. First, in the SAM, major merger and frequent minor mergers result in the growth of bulges and turn the galaxy into ET, while bulge formation is not connected to mergers as tightly as in SAM for the Illustris galaxies. In addition, the satellite stellar mass can decrease significantly due to tidal stripping before merging into the central galaxy in Illustris, while it does not decrease in the SAM model. This results in less mergers with large (stellar) mass ratios in the Illustris simulation, and less effect of mergers on shaping galaxy morphology.