THE DELAY OF POPULATION III STAR FORMATION BY SUPERSONIC STREAMING VELOCITIES
THE DELAY OF POPULATION III STAR FORMATION BY SUPERSONIC STREAMING VELOCITIES
复制标题
超音速流速度延迟了 III 族恒星的形成
DOI：
10.1088/0004-637x/736/2/147
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
V. Springel
中科院分区：
文献类型：
--
作者：
T. Greif;S. White;R. Klessen;V. Springel
最近的研究表明，暗物质和气体之间的相干相对流动速度为 30kms−1，在重组后直接以低于几 Mpc 的尺度渗透到宇宙中。在这里，我们使用一系列高分辨率移动网格计算来表明这些超音速运动显着影响迷你晕中气体的维氏化并延迟第一批恒星的形成。当气体在 z ∼ 20 处以大约 1 km s−1 的总体速度流入迷你晕时，额外的动量和能量输入减少了晕的气体分数和中心密度，将有效冷却所需的典型维里质量增加了三倍，并延迟了族 III 恒星的形成 Δz ≃ 4。值，这种效应在宇宙的大多数区域都很重要。因此，最小晕质量的增加意味着预计冷却并形成第三族恒星的迷你晕的绝对数量减少了一个数量级。我们进一步发现，流动速度增加了迷你晕气体的湍流速度色散，这可能会影响其破碎能力，从而改变第一批恒星的质量函数。
It has recently been demonstrated that coherent relative streaming velocities of order 30 km s−1 between dark matter and gas permeated the universe on scales below a few Mpc directly after recombination. Here we use a series of high-resolution moving-mesh calculations to show that these supersonic motions significantly influence the virialization of the gas in minihalos and delay the formation of the first stars. As the gas streams into minihalos with bulk velocities around 1 km s−1 at z ∼ 20, the additional momentum and energy input reduces the gas fractions and central densities of the halos, increasing the typical virial mass required for efficient cooling by a factor of three and delaying Population III star formation by Δz ≃ 4. Since the distribution of the magnitude of the streaming velocities is narrowly peaked around a non-negligible value, this effect is important in most regions of the universe. As a consequence, the increased minimum halo mass implies a reduction of the absolute number of minihalos that can be expected to cool and form Population III stars by up to an order of magnitude. We further find that the streaming velocities increase the turbulent velocity dispersion of the minihalo gas, which could affect its ability to fragment and hence alter the mass function of the first stars.
影响因子：
8.7
作者：
Komatsu, E.;Smith, K. M.;Wright, E. L.
通讯作者：
Wright, E. L.