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arXiv 1605.07548astro-ph.CO
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用观测值约束晕质量函数

Constraining the halo mass function with observations

Tiago Castro, Valerio Marra, Miguel Quartin

摘要:

宇宙中暗物质晕的丰度可用晕质量函数(HMF)来描述。它进入了大多数宇宙学分析,并参数化了原始扰动的线性增长如何与这些丰度相联系。有趣的是,这种联系可以近似地与宇宙学无关。这使得通过大规模模拟来详细绘制其近乎普遍的行为成为可能。然而,这种模拟可能会受到系统效应的影响,特别是如果包括重子物理。在本文中,我们问如何观察可以直接约束HMF。我们考虑的观测量是星系团数、星系团功率谱和Ia型超新星的透镜效应。我们的研究结果表明,DES是能够把第一个有意义的限制HMF,而欧几里德和J-PAS可以提供更强的约束,从国家的最先进的模拟。我们还发现,一个独立的测量集群质量是更重要的测量HMF比约束的宇宙学参数,可以大大提高晕质量函数的测定。因此,测量HMF可以用来交叉检查重子物理学的模拟及其实现。如果不能解释偏差,它甚至可以暗示新的物理学。

英文摘要:

The abundances of dark matter halos in the universe are described by the halo mass function (HMF). It enters most cosmological analyses and parametrizes how the linear growth of primordial perturbations is connected to these abundances. Interestingly, this connection can be made approximately cosmology independent. This made it possible to map in detail its near-universal behavior through large-scale simulations. However, such simulations may suffer from systematic effects, especially if baryonic physics is included. In this paper we ask how well observations can constrain directly the HMF. The observables we consider are galaxy cluster number counts, galaxy cluster power spectrum and lensing of type Ia supernovae. Our results show that DES is capable of putting the first meaningful constraints on the HMF, while both Euclid and J-PAS can give stronger constraints, comparable to the ones from state-of-the-art simulations. We also find that an independent measurement of cluster masses is even more important for measuring the HMF than for constraining the cosmological parameters, and can vastly improve the determination of the halo mass function. Measuring the HMF could thus be used to cross-check simulations and their implementation of baryon physics. It could even, if deviations cannot be accounted for, hint at new physics.

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