Halo mass function: baryon impact, fitting formulae, and implications for cluster cosmology
Halo mass function: baryon impact, fitting formulae, and implications for cluster cosmology
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DOI：
10.1093/mnras/stv2657
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发表时间：
2016-03-01
影响因子：
4.8
通讯作者：
Mohr, Joseph J.
中科院分区：
文献类型：
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作者：
Bocquet, Sebastian;Saro, Alex;Mohr, Joseph J.
我们使用一组流体力学和纯暗物质(DMonly)模拟来校准晕质量函数(HMF)。我们探索了重子的影响，提出了一种改进的球状过密度质量的参数化，并确定了我们的仅有DM型的HMF与以前发表的HMF之间的差异。我们使用磁性模拟，这是非常合适的，因为它们对重子的精确处理，高分辨率，以及高达3818MPC的大宇宙体积(3)。重子效应在全球范围内减少了星系团的质量，在给定质量时，这会导致星系团的数密度降低。当高红移z类似于2，并且对于大于或类似于10(14)M(圆点)的高质量M-200M时，这种效应消失。我们对南极望远镜(SPT)、普朗克和eROSITA对星系团调查的三种理想化近似进行了宇宙学分析。我们追问两个主要问题。(1)重子的影响是什么？-对于类SPT和类普朗克的样品，重子对宇宙学结果的影响可以忽略不计。然而，在类似eROSITA的情况下，忽略重子影响会导致对欧米茄(M)的低估约0.01，这与eROSITA的预期不确定性相当。(2)我们的DMonly HMF与以前的工作相比如何？-对于类似Planck的样本，使用我们的DMonly HMF获得的结果相对于使用Tinker等人获得的结果移动了类似或等于0.02的Delta(sigma(8)(Omega(M)/0.27)(0.3))。合身。这表明，使用我们的HMF将使普朗克星系团的结果与宇宙-微波-背景各向异性测量结果更好地吻合。最后，我们讨论了通过引入虚假的宇宙学敏感性的不充分的HMF参量化可能引入的偏差。
We use a set of hydrodynamical and dark matter-only (DMonly) simulations to calibrate the halo mass function (HMF). We explore the impact of baryons, propose an improved parametrization for spherical overdensity masses, and identify differences between our DMonly HMF and previously published HMFs. We use the Magneticum simulations, which are well suited because of their accurate treatment of baryons, high resolution, and large cosmological volumes of up to (3818 Mpc)(3). Baryonic effects globally decrease the masses of galaxy clusters, which, at a given mass, results in a decrease of their number density. This effect vanishes at high redshift z similar to 2 and for high masses M-200m greater than or similar to 10(14)M(circle dot). We perform cosmological analyses of three idealized approximations to the cluster surveys by the South Pole Telescope (SPT), Planck, and eROSITA. We pursue two main questions. (1) What is the impact of baryons? - for the SPT-like and the Planck-like samples, the impact of baryons on cosmological results is negligible. In the eROSITA-like case, however, neglecting the baryonic impact leads to an underestimate of Omega(m) by about 0.01, which is comparable to the expected uncertainty from eROSITA. (2) How does our DMonly HMF compare with previous work? - for the Planck-like sample, results obtained using our DMonly HMF are shifted by Delta(sigma(8)) similar or equal to (sigma(8)(Omega(m)/0.27)(0.3)) similar or equal to 0.02 with respect to results obtained using the Tinker et al. fit. This suggests that using our HMF would shift results from Planck clusters towards better agreement with cosmic-microwave-background anisotropy measurements. Finally, we discuss biases that can be introduced through inadequate HMF parametrizations that introduce false cosmological sensitivity.