Migration and kinematics in growing disc galaxies with thin and thick discs
Migration and kinematics in growing disc galaxies with thin and thick discs
复制标题
具有薄盘和厚盘的生长盘星系中的迁移和运动学
DOI：
10.1093/mnras/stx1483
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发表时间：
2017
影响因子：
4.8
通讯作者：
Aumer M
中科院分区：
文献类型：
--
作者：
Aumer M
本文分析了具有厚盘和薄盘的生长盘星系的N体模型中的盘加热和径向迁移。类似于薄盘模型，具有适当的非轴对称结构的星系再现观测约束径向盘加热和迁移到太阳邻域（Snhd）。厚圆盘的存在可以抑制非轴对称性，因此需要比只有薄圆盘的模型更高的重子暗物质分数。重子主导的模型，大约太阳radiusR 0的青睐，与银河系的数据。对于由内向外生长的盘，今天在R 0的厚盘恒星主要是向外迁移的。向外迁移的流体在垂直方向上是否比非迁移的流体热，取决于厚盘垂直速度弥散的径向梯度。在角动量上存在一个有效的上边界，诞生于星系中心的厚盘星可以通过迁移到达该上边界，这解释了R 0外高[α/Fe]序列的衰落。我们的模型比较以及Snhd运动学径向速度调查和Tycho-Gaia天体测量解决方案的数据。对于这样的比较，重要的是要考虑到方位角变化的运动学atR R 0和偏差的调查选择功能。巨分子云对薄圆盘恒星的垂直加热只受到厚圆盘的轻微影响。我们的模型预测更高的垂直速度色散的最古老的恒星比发现在Snhd年龄速度色散关系，可能是因为测量的不确定性或低估了我们的模型中的老冷星的数量。
We analyse disc heating and radial migration inN-body models of growing disc galaxies with thick and thin discs. Similar to thin-disc-only models, galaxies with appropriate non-axisymmetric structures reproduce observational constraints on radial disc heating in and migration to the Solar Neighbourhood (Snhd). The presence of thick discs can suppress non-axisymmetries and thus higher baryonic-to-dark matter fractions are required than in models that only have a thin disc. Models that are baryon dominated to roughly the Solar radiusR0are favoured, in agreement with data for the Milky Way. For inside–out growing discs, today’s thick-disc stars atR0are dominated by outwards migrators. Whether outwards migrators are vertically hotter than non-migrators depends on the radial gradient of the thick-disc vertical velocity dispersion. There is an effective upper boundary in angular momentum that thick-disc stars born in the centre of a galaxy can reach by migration, which explains the fading of the high [α/Fe] sequence outsideR0. Our models compare well to Snhd kinematics from Radial Velocity Survey and Tycho-Gaia Astrometric Solution data. For such comparisons, it is important to take into account the azimuthal variation of kinematics atR∼R0and biases from survey selection functions. The vertical heating of thin-disc stars by giant molecular clouds is only mildly affected by the presence of thick discs. Our models predict higher vertical velocity dispersions for the oldest stars than found in the Snhd age velocity dispersion relation, possibly because of measurement uncertainties or an underestimation of the number of old cold stars in our models.
影响因子：
4.8
作者：
Aumer M
通讯作者：
Aumer M
DOI：
10.3847/0004-637x/831/2/139
发表时间：
2016-09
期刊：
The Astrophysical Journal
影响因子：
--
作者：
M. Martig;I. Minchev;M. Ness;M. Fouesneau;H. Rix
通讯作者：
M. Martig;I. Minchev;M. Ness;M. Fouesneau;H. Rix
MOA-II 银河系微透镜约束：银河系内部暗物质比例较低，盘面接近最大
DOI：
--
发表时间：
2016
期刊：
影响因子：
--
作者：
C. Wegg;O. Gerhard;Matthieu Portail
通讯作者：
Matthieu Portail