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arXiv 0903.0729astro-ph.CO
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模拟高z宇宙:探测星系形成

Modeling the High-z Universe: Probing Galaxy Formation

S. Khochfar

摘要:

我们讨论了如何在高红移的条件不同,在低红移,以及什么样的影响是对星系人口。我们特别关注气体耗散的作用及其对维持高恒星形成率的影响,以及在合并中驱动恒星爆发。气体吸积到星系在高红移发生在晕动力学时间允许非常有效地持续恒星形成。此外,如果至少有20%的吸积能量转化为气体盘中的随机运动,冷吸积流就能够在高红移盘中驱动湍流。在一般情况下,我们发现,涉及星系合并的气体的分数是一个很强的函数的时间和增加的红移。一个模型相结合的作用,耗散合并和卫星星系的持续下降,允许再现观测到的早期型星系的红移的大小演化。此外,我们调查如何的光度函数的暗端的演变可以解释在底层的暗物质演化的演变。

英文摘要:

We discuss how the conditions at high redshift differ from those at low redshift, and what the impact is on the galaxy population. We focus in particular on the role of gaseous dissipation and its impact on sustaining high star formation rates as well as on driving star-bursts in mergers. Gas accretion onto galaxies at high redshifts occurs on a halo dynamical time allowing for very efficiently sustained star formation. In addition cold accretion flows are able to drive turbulence in high redshift disks at the level observed if at least 20% of the accretion energy is converted into random motion in the gaseous disk. In general we find that the fraction of gas involved in galaxy mergers is a strong function of time and increases with redshift. A model combining the role of dissipation during mergers and continued infall of satellite galaxies allows to reproduce the observed size-evolution of early-type galaxies with redshift. Furthermore we investigate how the evolution of the faint-end of the luminosity function can be explained in terms of the evolution of the underlying dark matter evolution.

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