Exploring extensions to the standard cosmological model and the impact of baryons on small scales
Exploring extensions to the standard cosmological model and the impact of baryons on small scales
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DOI：
10.1093/mnras/staa2059
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发表时间：
2020-04
影响因子：
4.8
通讯作者：
Sam G Stafford;Shaun T. Brown;I. McCarthy;A. Font;A. Robertson;Robert Poole-Mckenzie
中科院分区：
文献类型：
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作者：
Sam G Stafford;Shaun T. Brown;I. McCarthy;A. Font;A. Robertson;Robert Poole-Mckenzie
有人声称，宇宙学标准模型（ΛCDM）不能轻易解释相对小尺度上的大量观测，这激发了对标准模型的扩展。在这里，我们介绍了一套新的宇宙学模拟，系统地探讨了三个合理的扩展：温暖的暗物质，自相互作用的暗物质，和运行的标量谱指数的密度波动。当前的观测约束用于指定这些扩展附带的附加参数。我们研究了大范围的小尺度上的可观测指标，包括晕质量函数，密度和圆速度分布，卫星subhaloes的丰度，和晕浓度。对于任何给定的度量，扩展之间可以存在显著的退化。然而，在细节上，不同的扩展有数量上不同的质量和径向的依赖关系，这表明在一系列尺度上的多探针方法可以用来打破简并。我们还表明，在不同的扩展（与标准模型相比）的径向密度分布的相对影响收敛到显着更小的半径比绝对配置文件。我们使用EAGLE和ARTEMIS模拟的重子物理的影响，推导出的宇宙学趋势进行比较。重子物理学和宇宙学变化之间也存在显著的简并（两者对某些观测量有相似的幅度效应）。考虑到星系形成物理学模型和ΛCDM扩展中固有的不确定性，对两者进行系统和同时的探索是非常必要的。
It has been claimed that the standard model of cosmology (ΛCDM) cannot easily account for a number of observations on relatively small scales, motivating extensions to the standard model. Here, we introduce a new suite of cosmological simulations that systematically explores three plausible extensions: warm dark matter, self-interacting dark matter, and a running of the scalar spectral index of density fluctuations. Current observational constraints are used to specify the additional parameters that come with these extensions. We examine a large range of observable metrics on small scales, including the halo mass function, density, and circular velocity profiles, the abundance of satellite subhaloes, and halo concentrations. For any given metric, significant degeneracies can be present between the extensions. In detail, however, the different extensions have quantitatively distinct mass and radial dependencies, suggesting that a multiprobe approach over a range of scales can be used to break the degeneracies. We also demonstrate that the relative effects on the radial density profiles in the different extensions (compared to the standard model) are converged down to significantly smaller radii than are the absolute profiles. We compare the derived cosmological trends with the impact of baryonic physics using the EAGLE and ARTEMIS simulations. Significant degeneracies are also present between baryonic physics and cosmological variations (with both having similar magnitude effects on some observables). Given the inherent uncertainties both in the modelling of galaxy formation physics and extensions to ΛCDM, a systematic and simultaneous exploration of both is strongly warranted.