The impact of baryonic processes on the two-point correlation functions of galaxies, subhaloes and matter
The impact of baryonic processes on the two-point correlation functions of galaxies, subhaloes and matter
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DOI：
10.1093/mnras/stu482
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发表时间：
2013-10
影响因子：
4.8
通讯作者：
M. V. Daalen;J. Schaye;I. McCarthy;C. Booth;C. D. L. Observatory;L. S. N. I. F. R. A. Institute;L. D. O. Astronomy;Astrophysics;T. Physics
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文献类型：
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作者：
M. V. Daalen;J. Schaye;I. McCarthy;C. Booth;C. D. L. Observatory;L. S. N. I. F. R. A. Institute;L. D. O. Astronomy;Astrophysics;T. Physics
观测到的星系聚集和星系与质量的互相关性为宇宙学和星系形成模型提供了重要的限制。尽管与星系形成相关的耗散和反馈过程被认为会影响物质的分布，但基本上所有用于预测聚类数据的模型都是基于无碰撞模拟的。在这里，我们使用大型流体动力学模拟来研究星系的形成如何影响星系和subhaloes的自相关函数，以及它们与物质的互相关。我们表明，由于包含重子的变化不仅限于小尺度，甚至存在于由次晕质量选择的样品中。在r > 1 Mpc/h的重子运行中，由次晕质量团选择的样品比重子运行强约10%，并且这种差异随着较小的分离而增加。虽然包含重子在所有尺度上都增强了固定次晕质量的聚集，但次晕与物质的互相关效应的符号可以随半径而变化。我们表明，大尺度效应是由于与星系形成相关的强反馈引起的次晕质量的变化，因此可能不会影响由数密度选择的样本。然而，在尺度r < r_vir上，在考虑晕下质量的变化后，仍然存在显著差异。我们的结论是，预测的星系星系和星系的质量集群模型的基础上碰撞模拟将有误差大于10%的次百万分之一尺度上，除非模拟结果进行修改，以正确地考虑重子的质量和卫星的分布的影响。
The observed clustering of galaxies and the cross-correlation of galaxies and mass provide important constraints on both cosmology and models of galaxy formation. Even though the dissipation and feedback processes associated with galaxy formation are thought to affect the distribution of matter, essentially all models used to predict clustering data are based on collisionless simulations. Here, we use large hydrodynamical simulations to investigate how galaxy formation affects the autocorrelation functions of galaxies and subhaloes, as well as their cross-correlation with matter. We show that the changes due to the inclusion of baryons are not limited to small scales and are even present in samples selected by subhalo mass. Samples selected by subhalo mass cluster ~10% more strongly in a baryonic run on scales r > 1Mpc/h, and this difference increases for smaller separations. While the inclusion of baryons boosts the clustering at fixed subhalo mass on all scales, the sign of the effect on the cross-correlation of subhaloes with matter can vary with radius. We show that the large-scale effects are due to the change in subhalo mass caused by the strong feedback associated with galaxy formation and may therefore not affect samples selected by number density. However, on scales r < r_vir significant differences remain after accounting for the change in subhalo mass. We conclude that predictions for galaxy-galaxy and galaxy-mass clustering from models based on collisionless simulations will have errors greater than 10% on sub-Mpc scales, unless the simulation results are modified to correctly account for the effects of baryons on the distributions of mass and satellites.