...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The Astrophysical Journal. Supplement Series >The overdensity and masses of the friends-of-friends halos and universality of halo mass function
【24h】

The overdensity and masses of the friends-of-friends halos and universality of halo mass function

机译：友好朋友的过度和群众霍洛斯的晕圈和Halo质量功能的普遍性

获取原文
获取原文并翻译 | 示例
   

获取外文期刊封面封底 >>

       
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The friends-of-friends algorithm (hereafter FOF) is a percolation algorithm which is routinely used to identify dark matter halos from N-body simulations. We use results from percolation theory to show that the boundary of FOF halos does not correspond to a single density threshold but to a range of densities close to a critical value that depends upon the linking length parameter, b. We show that for the commonly used choice of b = 0.2, this critical density is equal to 81.62 times the mean matter density. Consequently, halos identified by the FOF algorithm enclose an average overdensity which depends on their density profile (concentration) and therefore changes with halo mass, contrary to the popular belief that the average overdensity is ～180. We derive an analytical expression for the overdensity as a function of the linking length parameter b and the concentration of the halo. Results of tests carried out using simulated and actual FOF halos identified in cosmological simulations show excellent agreement with our analytical prediction. We also find that the mass of the halo that the FOF algorithm selects crucially depends upon mass resolution. We find a percolation-theory-motivated formula that is able to accurately correct for the dependence on number of particles for the mock realizations of spherical and triaxial Navarro-Frenk-White halos. However, we show that this correction breaks down when applied to the real cosmological FOF halos due to the presence of substructures. Given that abundance of substructure depends on redshift and cosmology, we expect that the resolution effects due to substructure on the FOF mass and halo mass function will also depend on redshift and cosmology and will be difficult to correct for in general. Finally, we discuss the implications of our results for the universality of the mass function.
机译：朋友们朋友算法（以下，所述FOF）是一种渗透算法，其通常用于识别来自N-sural模拟的暗物质晕。我们使用渗滤理论的结果表明FOF晕晕的边界不对应于单个密度阈值，而是靠近临界值的密度范围，这取决于链接长度参数B。我们表明，对于B = 0.2的常用选择，这种临界密度等于平均电量密度的81.62倍。因此，由FOF算法识别的HalO封装平均过度，这取决于它们的密度曲线（浓度），因此与晕骨变化，与平均过度密度为约180的流行相反。我们从连接长度参数B的函数和光环浓度的函数获得过度密度的分析表达。在宇宙模拟中确定的使用模拟和实际FOF光环进行的试验结果表现出与我们的分析预测相一致。我们还发现FOF算法选择的光环的质量在大致取决于质量分辨率。我们发现渗透理论激励的公式，该配方可以准确地校正对球形和三轴纳瓦罗 - 弗雷诺克白光圈的模拟的颗粒数量的依赖性。然而，我们表明，由于存在子结构，在应用于真实宇宙学FOF晕圈时，这种校正会破坏。鉴于富裕的子结构取决于红移和宇宙学，我们预计由于FOF质量和光环质量功能的子结构引起的分辨率效应也将取决于红移和宇宙学，一般难以纠正。最后，我们讨论了我们对质量功能普遍性的结果的影响。

著录项

  • 来源
  • 作者

    More S.; Kravtsov A.V.; Dalal N.; Gottl?ber S.;

  • 作者单位

    Kavli Institute for Cosmological Physics Enrico Fermi Institute University of Chicago Chicago IL 60637 United States;

    Kavli Institute for Cosmological Physics Enrico Fermi Institute University of Chicago Chicago IL 60637 United States;

    Canadian Institute for Theoretical Astrophysics University of Toronto 60 St. George Street Toronto ON M5S 3H8 Canada;

    Astrophysikalisches Institut Potsdam An der Sternwarte 16 14482 Potsdam Germany;

  • 收录信息
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 天体物理学;
  • 关键词

    cosmology: theory; dark matter; methods: numerical;

    机译：宇宙学：理论;暗物质;方法：数值;

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号