层次宇宙中Galerkin的结构和动力学性质：尺寸和比角动量
Structural and Dynamical Properties of Galaxies in a Hierarchical Universe: Sizes and Specific Angular Momenta
摘要：
我们使用最先进的半解析模型来研究星系的大小和特定的角动量。我们的模型包括一个特定的治疗不同的星系组件之间的角动量交换。盘尺度半径估计从气体/恒星盘的角动量，而隆起的大小估计假设能量守恒。预测的大小-质量和角动量-质量关系是在公平的协议与观测测量在当地的宇宙，提供了一个治疗过程中的主要合并气体耗散。我们的磁盘不稳定性的治疗导致不切实际的小半径通过这个通道形成的凸起，并预测中央和卫星早期型星系的大小-质量关系之间的偏移，这是没有观察到的。该模型再现所观察到的依赖形态的大小-质量关系，并预测特定的角动量和冷气体含量之间的强相关性。这种相关性是星系演化的自然结果：富含气体的星系居住在较小的晕中，并逐渐形成恒星直到今天，而缺乏气体的星系则居住在大质量的晕中，这些晕在早期形成了它们的大部分恒星，当时它们的母晕的角动量很低。星系的动力学和结构特性会受到恒星反馈的不同处理的强烈影响，因为这会改变它们的恒星形成历史。通过快速模吸积的气体的较高角动量对今天大质量星系的性质没有显著影响，但对红移较高的低质量星系有更重要的影响。
英文摘要：
We use a state-of-the-art semi-analytic model to study the size and the specific angular momentum of galaxies. Our model includes a specific treatment for the angular momentum exchange between different galactic components. Disk scale radii are estimated from the angular momentum of the gaseous/stellar disk, while bulge sizes are estimated assuming energy conservation. The predicted size--mass and angular momentum--mass relations are in fair agreement with observational measurements in the local Universe, provided a treatment for gas dissipation during major mergers is included. Our treatment for disk instability leads to unrealistically small radii of bulges formed through this channel, and predicts an offset between the size--mass relations of central and satellite early-type galaxies, that is not observed. The model reproduces the observed dependence of the size--mass relation on morphology, and predicts a strong correlation between specific angular momentum and cold gas content. This correlation is a natural consequence of galaxy evolution: gas-rich galaxies reside in smaller halos, and form stars gradually until present day, while gas-poor ones reside in massive halos, that formed most of their stars at early epochs, when the angular momentum of their parent halos is low. The dynamical and structural properties of galaxies can be strongly affected by a different treatment for stellar feedback, as this would modify their star formation history. A higher angular momentum for gas accreted through rapid mode does not affect significantly the properties of massive galaxies today, but has a more important effect on low-mass galaxies at higher redshift.
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