Effects of feedback on the morphology of galaxy discs
Effects of feedback on the morphology of galaxy discs
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DOI：
10.1111/j.1365-2966.2005.09525.x
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发表时间：
2005-03
影响因子：
4.8
通讯作者：
T. Okamoto;V. Eke;C. Frenk;A. Jenkins
中科院分区：
文献类型：
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作者：
T. Okamoto;V. Eke;C. Frenk;A. Jenkins
我们进行了流体动力学模拟星系形成的冷暗物质（ACDM）宇宙。我们已经跟踪了暗物质晕中星系的形成，选择了一个相对安静的近期合并历史，使用不同的星星形成和反馈模型。在所有情况下，我们都采用了星际介质的多相描述，并模拟了星星在静止和爆发模式下的形成。我们已经探索了两个触发恒星爆发-强烈的冲击和高气体密度-考虑到恒星在爆发中可能形成头重脚轻的初始质量函数的可能性。我们发现，星系的最终形态是非常敏感的星星形成和反馈的建模。从相同的初始条件开始，跨越整个哈勃类型范围的星系，B波段盘与总光度比从0.2到0.9不等，可以在相同的暗物质晕中形成。高气体密度导致星爆的模型（与活动星系核产生反馈的模型在性质上类似）产生高能风，并导致星系具有早期形态。模型中，恒星爆发是由强冲击导致扩展光盘。在这种情况下，与爆发相关的反馈抑制了小晕中重子的坍缩，帮助创造了一个热气体库，可以在z = 1之后冷却，随后是大量的动力学活动，建立了晕。然后这些气体冷却形成一个扩展的年轻恒星盘。
We have performed hydrodynamic simulations of galaxy formation in a cold dark matter (ACDM) universe. We have followed galaxy formation in a dark matter halo, chosen to have a relatively quiet recent merger history, using different models for star formation and feedback. In all cases, we have adopted a multiphase description of the interstellar medium and modelled star formation in quiescent and burst modes. We have explored two triggers for starbursts -strong shocks and high gas density - allowing for the possibility that stars in the burst may form with a top-heavy initial mass function. We find that the final morphology of the galaxy is extremely sensitive to the modelling of star formation and feedback. Starting from identical initial conditions, galaxies spanning the entire range of Hubble types, with B-band disc-to-total luminosity ratios ranging from 0.2 to 0.9, can form in the same dark matter halo. Models in which starbursts are induced by high gas density (qualitatively similar to models in which feedback is produced by active galactic nuclei) generate energetic winds and result in galaxies with an early-type morphology. Models in which the starbursts are induced by strong shocks lead to extended discs. In this case, the feedback associated with the bursts suppresses the collapse of baryons in small haloes, helping to create a reservoir of hot gas that is available for cooling after z ≃ 1, following the bulk of the dynamical activity that builds up the halo. This gas then cools to form an extended, young stellar disc.