Impact of the Relative Motion between the Dark Matter and Baryons on the First Stars
Impact of the Relative Motion between the Dark Matter and Baryons on the First Stars
复制标题
暗物质和重子之间的相对运动对第一颗恒星的影响
DOI：
10.1111/j.1365-2966.2012.21318.x
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
C. Hirata
中科院分区：
文献类型：
--
作者：
A. Fialkov;R. Barkana;Dmitriy Tseliakhovich;C. Hirata
最近的研究表明，暗物质与重子的初始超音速相对速度对高红移星系的形成有重要影响。我们研究了这种相对运动对恒星形成晕分布的影响，以及对第一颗星星形成红移的影响。我们包括一个新的方面，在最近的模拟中发现，通过拟合他们的结果，以获得分子冷却所需的空间变化的最小晕质量的相对速度效应。因此，相对速度有三个独立的效果：抑制晕丰度，抑制每个晕内的气体含量，并提高最小冷却质量。我们表明，两个supplies（气体含量和晕丰度）的主要影响的小minihalos，不能形成恒星，而冷却质量提升结合丰度抑制，以产生秩序统一波动的恒星密度。我们量化了星系的大尺度不均匀性，发现68%的星星形成（在3 Mpc尺度上平均）局限于z=20时体积的35%（z=40时仅为18%）。此外，我们估计第一颗星星的红移为z ~ 65，其中包括由于相对速度引起的延迟Dz ~ 5。
Recently the initial supersonic relative velocity between the dark matter and baryons was shown to have an important effect on galaxy formation at high redshift. We study the impact of this relative motion on the distribution of the star-forming halos and on the formation redshift of the very first star. We include a new aspect of the relative velocity effect found in recent simulations by fitting their results to obtain the spatially-varying minimum halo mass needed for molecular cooling. Thus, the relative velocities have three separate effects: suppression of the halo abundance, suppression of the gas content within each halo, and boosting of the minimum cooling mass. We show that the two suppressions (of gas content and of halo abundance) are the primary effects on the small minihalos that cannot form stars, while the cooling mass boost combines with the abundance suppression to produce order unity fluctuations in stellar density. We quantify the large-scale inhomogeneity of galaxies, finding that 68% of the star formation (averaged on a 3 Mpc scale) is confined to 35% of the volume at z=20 (and just 18% at z=40). In addition, we estimate the redshift of the first star to be z ~ 65, which includes a delay of Dz ~ 5 due to the relative velocity.
影响因子：
8.7
作者：
Komatsu, E.;Smith, K. M.;Wright, E. L.
通讯作者：
Wright, E. L.