Galaxies–intergalactic medium interaction calculation – I. Galaxy formation as a function of large-scale environment
Galaxies–intergalactic medium interaction calculation – I. Galaxy formation as a function of large-scale environment
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DOI：
10.1111/j.1365-2966.2009.15402.x
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发表时间：
2009-06
影响因子：
4.8
通讯作者：
R. Crain;T. Theuns;C. D. Vecchia;V. Eke;C. Frenk;A. Jenkins;S. Kay;John A. Peacock Frazer R. Pearce;J. Schaye;V. Springel;P. Thomas;S. White;R. P. C. W. -. Icc;U. O. D. -. Cas;Swinburne University of Technology - University of Antwerp - Bank-Swinburne-University-of-Technology-University-of-122486616;U. O. H. IfA;U. Sussex
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文献类型：
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作者：
R. Crain;T. Theuns;C. D. Vecchia;V. Eke;C. Frenk;A. Jenkins;S. Kay;John A. Peacock Frazer R. Pearce;J. Schaye;V. Springel;P. Thomas;S. White;R. P. C. W. -. Icc;U. O. D. -. Cas;Swinburne University of Technology - University of Antwerp - Bank-Swinburne-University-of-Technology-University-of-122486616;U. O. H. IfA;U. Sussex
[摘要]我们提出了流体动力学模拟的第一个结果，这些结果是在千禧年模拟中绘制的半径约为20 Mpc/h的球形区域中，星系形成到z=0。这些区域的超密度偏离宇宙平均值（-2，-1，0，+1，+2）σ，其中σ是z=1.5时的均方根质量波动，尺度约为20 Mpc/h。模拟的质量分辨率高达10^6兆太阳/小时，涵盖了整个大尺度环境范围，并允许将统计数据外推到整个500兆秒差距/小时的千禧年体积。它们包括气体冷却、来自电离背景的光加热、SNe反馈和风，但没有活动星系核。我们发现，在z <~ 10的特定的SFR密度系统地从区域到区域的变化高达一个数量级，但全球值，平均在所有体积，再现观测数据。大质量的致密星系，类似于在GOODS场中观察到的星系，早在z=6时就在过密区域形成，但直到z~3才出现在欠密区域。这些环境的变化不是由星星的形成属性对环境的依赖性引起的，而是由晕质量函数从一个环境到另一个环境的强烈变化引起的，更大质量的晕优先在密度更大的区域形成。在所有时期，恒星在圆速度约为250 km/s的晕中形成的效率最高。然而，星星的形成历史表现出一种“缩小”的形式（即使在没有活动星系核的情况下）：由z=0的大质量星系组成的恒星大多在z=1-2时形成，而由较小星系组成的恒星通常在较晚的时间形成。然而，需要额外的反馈来限制大质量星系后期的星星形成。
[Abridged] We present the first results of hydrodynamical simulations that follow the formation of galaxies to z=0 in spherical regions of radius ~20 Mpc/h drawn from the Millennium Simulation. The regions have overdensities that deviate by (-2, -1, 0, +1, +2)sigma from the cosmic mean, where sigma is the rms mass fluctuation on a scale of ~20Mpc/h at z=1.5. The simulations have mass resolution of up to 10^6 Msun/h, cover the entire range of large-scale environments and allow extrapolation of statistics to the entire 500 (Mpc/h)^3 Millennium volume. They include gas cooling, photoheating from an ionising background, SNe feedback and winds, but no AGN. We find that the specific SFR density at z <~ 10 varies systematically from region to region by up to an order of magnitude, but the global value, averaged over all volumes, reproduces observational data. Massive, compact galaxies, similar to those observed in the GOODS fields, form in the overdense regions as early as z=6, but do not appear in the underdense regions until z~3. These environmental variations are not caused by a dependence of the star formation properties on environment, but rather by a strong variation of the halo mass function from one environment to another, with more massive haloes forming preferentially in the denser regions. At all epochs, stars form most efficiently in haloes of circular velocity ~ 250 km/s. However, the star formation history exhibits a form of "downsizing" (even in the absence of AGN): the stars comprising massive galaxies at z=0 have mostly formed by z=1-2, whilst those comprising smaller galaxies typically form at later times. However, additional feedback is required to limit star formation in massive galaxies at late times.