标题： LCDM早期结构 显示英文标题

标题： Early structure in LCDM

摘要： 我们采用一种新颖的技术，模拟了原星团区域中最重的前身天体从红移约80（当时其质量约为10倍太阳质量）到今天的变化过程。 我们的N体重力模拟序列使我们能够详细研究暗物质天体本身及其环境的结构。 我们的有效分辨率在红移49、29、12、5和0时最佳，此时主天体的质量分别为1.2e5、5e7、2e10、3e12和8e14太阳质量/单位哈勃常数，并且在其引力半径内包含约1e6个模拟粒子。 扩展的Press-Schechter理论正确预测了这种快速增长以及我们在主天体周围区域早期发现的大质量晕的显著过量。 尽管这些区域的大尺度结构与今日对应物的缩放版本差异很大，但主天体的内部结构却惊人地相似。 在这个天体中，分子氢冷却可能早在红移49时开始，而原子氢冷却在红移39时变得有效。 如果第一颗恒星形成于引力温度约2000K的晕中，那么它们在红移49时的共动丰度将类似于今日矮星系的丰度，而它们的共动相关长度约为2.5Mpc/单位哈勃常数。 显示英文摘要

摘要： We use a novel technique to simulate the growth of the most massive progenitor of a protocluster region from redshift z~80, when its mass was about 10 Msun until the present day. Our nested sequence of N-body resimulations allows us to study in detail the structure both of the dark matter object itself and of its environment. Our effective resolution is optimal at redshifts of 49, 29, 12, 5 and 0 when the dominant object has mass 1.2e5, 5e7, 2e10, 3e12 and 8e14 Msun/hrespectively, and contains ~1e6 simulation particles within its virial radius. Extended Press-Schechter theory correctly predicts both this rapid growth and the substantial overabundance of massive haloes we find at early times in regions surrounding the dominant object. Although the large-scale structure in these regions differs dramatically from a scaled version of its present-day counterpart, the internal structure of the dominant object is remarkably similar. Molecular hydrogen cooling could start as early as z~49 in this object, while cooling by atomic hydrogen becomes effective at z~39. If the first stars formed in haloes with virial temperature ~2000, their comoving abundance by z=49 would be similar to that of dwarf galaxies today, while their comoving correlation length would be ~2.5Mpc/h.